Development Next Steps
Contents
Note to Reviewers
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Development Next Steps
Contents
1. General Risk Factors and Vulnerabilities
4.1 Individual Risk Factors
4 2 Practitioner-Client Risk Factors
4 3 Interpersonal Risk Factors
4.4 Setting-Specific Risk Factors
4.5 Risk Factors Related to Preparation and Integration
4 6 Cultural and Spiritual Risk Factors
4 7 Legal Context
4 8 Socioeconomic and Equity-Related Risk Factors
4.9 Contamination and Quality Risk Factors
4 10 Adverse Events Associated with All Psychedelic Substances
2 Substance Risk Profiles
Psilocybin
Overview
Psilocybin-Specific Risk Factors
Risk Factors Related to Routes of Administration
Oral Administration
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Variability in Potency and Dosing Inaccuracy
Sourcing from Unregulated Markets
Adulteration and Contaminants
Storage and Degradation
Lack of Testing and Quality Control
Contraindications
Adverse Events
Psychological Effects
Physiological Effects
Psychological Effects
Physiological Effects
Cognitive and Functional Effects
Other Considerations
Adverse Events of Microdosing
LSD
Overview
LSD-Specific Risk Factors
LSD-Specific Risk Factors Related to Routes of Administration
LSD-Specific Risk Factors Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
Psychological Effects
Physiological Effects
Psychological Effects
Physiological Effects
Adverse Events of Microdosing
2C-X (2C-B, 2C-C, etc.) Family
Overview
2c Family-Specific Risk Factors
Risk Factors Related to Routes of Administration
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
DMT
Overview
DMT-Specific Risk Factors
Risk Factors Related to Routes of Administration
Adverse Events Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
5-MEO-DMT
Overview
5-MEO-DMT-Specific Risk Factors
Risk Factors Related to Routes of Administration
Adverse Events Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
Iboga / Ibogaine
Overview
Iboga/Ibogaine-Specific Risk Factors
Risk Factors Related to Routes of Administration
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
MDMA
Overview
MDMA-Specific Risk Factors
Risk Factors Related to Routes of Administration
Risks Related to Quality, Sourcing, and Potential Contamination Contraindications
Adverse Events
Ketamine
Overview
Ketamine-Specific Risk Factors
Risk Factors Related to Routes of Administration
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
Ayahuasca
Overview
Ayahuasca-Specific Risk Factors
Risk Factors Related to Routes of Administration
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Contraindications
Adverse Events
3. Harm Reduction and Safety Measures
6 1 Screening and Consent
6 2 Setting
6 3 Dose and Substance Preparation
6.4 Supervision and Facilitation
6.5 Preparation
6 6 Integration
6 7 Crisis Intervention and Emergency Response
6.8 Public Education
6.9 Online Communities
6 10 Peer Support Networks
6 11 Accessibility and Inclusion
7. Research Gaps
Substance-Specific Research Gaps
References
Psilocybin
1. General Risk Factors and Vulnerabilities
Psychedelics can produce highly variable and unpredictable experiences (Neitzke-Spruill et al 2024; Henríquez-Hernández et al 2023; Preller & Vollenweider, 2018) Even with proper preparation, there's no guarantee of a positive experience, and negative reactions can sometimes occur (Amsterdam et al., 2011; Holoyda 2023; Carbonaro et al., 2016; Evans et al., 2023).
Keeping in mind the variation of risk factors, there are a number of risk factors that are common to the use of all psychedelic substances These will be outlined below but not repeated in each substance’s profile. When reading the individual substance sections, remember to refer back to this list, as every substance examined in this review of literature carries these universal risks.
4.1 Individual Risk Factors
Responses to psychedelics vary considerably among individuals (Rosenblat et al 2023; Scala et al 2024; Bălăeţ 2022b; Aday et al , 2021) Below is a list of the various individual differences that can affect how people react to the presence of psychedelic substances in the body
Physiological Factors
● Cardiovascular conditions: Psychedelics can increase blood pressure, body temperature, and heart rate (Wsół, 2023; Nahlawi et al , 2025) This poses a risk for individuals with pre-existing heart conditions or hypertension (Anderson et al., 2020). Individuals with cardiovascular diseases are at increased risk of direct toxicity from psychedelics, especially in overdose (Marazziti et al. 2024).
● Obstructive respiratory syndromes: These conditions can also increase the risk of direct toxicity in overdose situations (Marazziti et al 2025)
● Epilepsy: Those with epilepsy or a family history of epilepsy are often excluded from clinical trials of psychedelics due to concerns about seizures (Simonsson et al , 2022)
Psychiatric Factors
● Pre-existing psychological conditions: Individuals with pre-existing mental health conditions, particularly those involving psychosis, anxiety, or mood disorders, are at an increased risk of experiencing challenging or destabilizing experiences with psychedelics (Gomez-Escolar et al. 2024; Aday et al. 2021; Ghaznavi et al. 2025; Izmi, Carhart-Harris, and Kettner 2024; Schlag et al 2022; White et al 2024; Bremler et al 2023)
● Psychotic disorders: Individuals with a personal or family history of psychotic disorders such as schizophrenia or schizophreniform disorders are at a higher risk of experiencing prolonged psychotic reactions or exacerbation of their condition after psychedelic use ( Honk et al 2024; Henningfield et al 2023; Johnson et al , 2008; Aday et al 2021; Breeksema et al 2022; Ghaznavi et al 2025; Gomez-Escolar et al 2024; White et al 2024) Although some research suggests low risk of a psychedelic-induced psychotic episode, this risk is increased in naturalistic, non-clinical settings without prior patient selection (Carbonaro et al. 2016).
● Bipolar disorder: Similar to psychotic disorders, individuals with a personal or family history of bipolar disorder may be more vulnerable to adverse outcomes, including manic episodes, after psychedelic use (Honk et al 2024) However, recent research on psychedelic-assisted therapy for treatment-resistant bipolar II depression showed no increases in mania or hypomania, suggesting that it may be safe for this specific population (Honk et al. 2024). For these individuals, careful screening, preparation, and support are essential if LSD use is considered (Marrocu et al., n.d.; Sabé et al., 2024).
● Personality disorders: Individuals with a history of personality disorders have a 31% chance of experiencing negative responses to psychedelic use (Marrocu et al , n d ), and one study indicated a greater than four-fold elevated risk of adverse psychological response in this population (Marrocu et al , n d ) A history of personality disorders may be associated with more negative long-term responses as well (Bremler et al 2023; Marrocu et al., n.d.).
● Anxiety and depression: Individuals with pre-existing anxiety or depression may experience a worsening of their symptoms after psychedelic use (Bremler et al 2023) A study found that anxiety symptoms arose or worsened in 87% of participants who experienced negative psychological responses to psychedelics (Bremler et al. 2023).
● Suicidality: While some studies suggest that psychedelics can reduce suicidality at the population level (Hendricks et al 2015), there is concern that some individuals may have an increased risk of suicide after psychedelic experiences (Kruger et al 2024) Suicidal ideation was reported by some participants in a clinical trial of psilocybin for treatment-resistant depression, but the direct impact of the psychedelic intervention on these symptoms remains unclear, especially since it emerged in the three weeks following treatment (Romeo et al. 2024).
● Poor coping skills: Individuals with poor coping skills and those who tend to be emotionally unstable may be more likely to have negative experiences with psychedelics (Studerus et al. 2011). Emotional lability rapid and extreme mood fluctuations can make it harder to navigate the intense psychological effects of the drug (Studerus et al , 2011)
● Life situations: Individuals who are undergoing stressful life circumstances or major life changes are more likely to experience anxiety or panic during their trip, which can lead to longer-term psychological distress (Bremler et al , 2023)
● Unprocessed trauma: Past trauma can resurface during psychedelic experiences, potentially leading to distress (Bremler et al 2023; Gorman et al 2021; Weiss et al 2023). Individuals with a history of trauma may benefit from specialized therapeutic
support before, during, and after psychedelic experiences to process these memories safely (Bremler et al 2023; Gorman et al 2021; Weiss et al 2023).
Age and Developmental Stage
● Increased vulnerability to negative psychological effects: Adolescents and young adults may be more vulnerable to the potential negative psychological effects of psychedelics (Marazziti et al , 2024; Breeksema et al 2022; Izmi, Carhart-Harris, and Kettner 2024; Breeksema et al. 2022; Bremler et al. 2023; Malcolm and Thomas 2022). The developing brain may be more susceptible to disruptions in neurotransmitter systems and the psychological impact of intense experiences, especially in cases of high doses or challenging environments (Izmi, Carhart-Harris, and Kettner 2024; Cameron, Nazarian, and Olson 2020; Bremler et al 2023) One study showed that 53% of participants experiencing negative effects from psychedelic use were under 25 (Bremler et al. 2023).
● Increased use of emergency services: In general, younger people tend to have higher rates of emergency medical treatment after using psychedelics (Marazziti et al. 2024). A study found that the majority of poison control cases relating to LSD and psilocybin were adolescents aged 13 to 19 (Malcolm and Thomas 2022)
Personality Traits and Psychological Vulnerabilities
● Suggestibility: Psychedelics can increase suggestibility, making individuals more susceptible to external influences or internal negative thoughts (Neitzke-Spruill et al 2024) Some older studies suggest that individuals with a tendency towards suggestibility may be more prone to negative experiences with psychedelics (Halpern, Lerner, and Passie 2018).
● Dysfunctional attitudes: Individuals with more dysfunctional attitudes, as measured by the Dysfunctional Attitude Scale, may have a more challenging experience The scale measures the presence and intensity of dysfunctional beliefs (Anderson et al 2019)
● Difficulties with surrender: A participant's willingness to surrender during a psychedelic experience is a strong predictor of a positive experience, while preoccupation and rumination are associated with difficult experiences and poorer long-term outcomes (Fogg et al , 2021)
● Prior psychological trauma: Individuals with a history of trauma, particularly if unresolved, may be more likely to have a negative experience with psychedelics or a flashback (Scala et al 2024)
● Neuroticism: High neuroticism is a robust predictor of challenging experiences, including anxiety, panic, and paranoia (Barrett, Johnson, and Griffiths 2017; Breeksema et al 2022; 2022; Gorman et al 2021) Individuals with high levels of neuroticism may find the intense emotional and psychological effects of psychedelics overwhelming (Barrett, Johnson, and Griffiths 2017; Breeksema et al 2022; 2022; Gorman et al 2021)
● Openness: Openness to experience is associated with positive and mystical experiences (Breeksema et al. 2022; Aday et al. 2021). Individuals who are more open
may be better equipped to embrace the novel and sometimes challenging psychological states induced by psychedelics (Breeksema et al. 2022; Aday et al. 2021).
● Increase in likelihood of seeking help: Individuals with a history of psychological issues may be more likely to seek treatment for negative symptoms after having a challenging experience (Holoyda, 2023).
Previous Experiences with Substances
● Lack of experience: First-time users or those with little experience may be less prepared to handle the powerful effects of the drug, making them more susceptible to overwhelming experiences (Bodnár and Kakuk, 2019; Lancelotta and Davis 2020b)
● Lack of preparedness: Inadequate preparation for the psychedelic experience can contribute to adverse outcomes (Aday et al. 2020; Garcia-Romeu and Richards 2018; Aday et al 2020) This includes lack of understanding of what to expect from the experience, poor intention setting, or not having strategies for navigating difficult experiences (Henningfield et al. 2023; Palitsky et al., n.d.).
● Prior challenging experiences: Previous difficult experiences with psychedelics can increase the likelihood of similar challenges in the future(Aday et al. 2021; Evans et al. 2023; Palmer and Maynard 2022) Individuals who have had negative reactions to psychedelics in the past should exercise caution and seek professional guidance before considering further use.(Aday et al. 2021; Evans et al. 2023; Palmer and Maynard 2022)
Patterns of Use and Dosage
● High dosages: Higher doses of any psychedelic are associated with an increased risk of adverse events, both psychological and physiological (Anderson et al. 2019; Baumeister, Tojo, and Tracy 2015; Bălăeţ 2022b; Breeksema et al. 2022; Gomez-Escolar et al 2024; Husain, Umer, and Mulsant 2022; Johnson, Richards, and Griffiths 2008; Bremler et al 2023; Henríquez-Hernández et al 2023) The dose-response relationship means that as the dose increases, the likelihood of negative effects increases. The greater the purity of a psychedelic and the more potent it is by weight, the easier it is to overdose, increasing the importance of psychedelic care as a response to the overdose (Engel et al. 2024a).
● Frequency of use: Regular use of certain types of psychedelics (e g 25I-NBOMe) is associated with a higher risk of developing HPPD (“A Retrospective Analysis of the ‘Neverending Trip’ after Administration of a Potent Full Agonist of 5-HT2A Receptor –25I-NBOMe,” n.d.). Those who use psychedelics several times a month regularly have a 67% chance of chronic or prolonged effects, compared to single-use at 20% (“A Retrospective Analysis of the ‘Neverending Trip’ after Administration of a Potent Full Agonist of 5-HT2A Receptor – 25I-NBOMe,” n d )
● Unknown drug quantity/purity: A significant risk factor with any illicit drug is the lack of quality control (Baumeister, Tojo, and Tracy 2015; Hirschfeld et al 2021) Users are often unaware of the quantity or purity of the substance, which can increase the risk of adverse events (Bremler et al. 2023), potentially leading to accidental overdoses or
unexpected reactions (Hirschfeld et al 2021) Most participants in one study who had adverse effects reported either uncertainty about their dose, or having taken a higher dose than normal (Bremler et al. 2023).
● Polydrug use: The co-use of psychedelics with other substances, such as alcohol or other drugs can lead to a higher incidence of adverse effects (Kopra et al 2025; Marazziti et al 2024) This is especially true when psychedelic substances are combined with drugs that affect serotonin levels (Breeksema et al 2022; Ghaznavi et al 2025; Hirschfeld et al. 2021; Morton et al. 2023), as this can lead to serotonin syndrome, a potentially life-threatening condition (Gomez-Escolar et al. 2024; Aday, Bloesch, and Davoli 2020; Ashraf 2024; Malcolm and Thomas 2022) Polydrug use was identified as the most common theme in psychedelic-related deaths (Kopra et al 2025)
● Method of administration:
4.2 Practitioner-Client Risk Factors
The power dynamics inherent in the practitioner-client relationship during psychedelic-assisted experiences can create vulnerabilities for clients, increasing the risk of adverse events and harms (Calder and Hasler 2023; Fonzo, Nemeroff, and Kalin 2025; Marcus 2023; Neitzke-Spruill et al 2024) These risks stem from the intense, intimate, and often vulnerable nature of the therapeutic relationship during psychedelic experiences (Garcia-Romeu and Richards 2018; Modlin et al. 2023). The heightened vulnerability of clients during psychedelic experiences can make them targets of exploitation, including sexual abuse, financial manipulation, and emotional coercion (Marcus 2023; Calder and Hasler 2023; Neitzke-Spruill et al 2024; Kelly et al 2023; Peterson et al. 2023; Rosenbaum et al. 2024; Villiger 2024; 2024). These risks are outlined below
Therapeutic Alliance and Transference Issues
● Impaired judgment:The altered state induced by psychedelics can heighten a client’s suggestibility and vulnerability, making them more susceptible to a practitioner's influence (Dupuis 2021; Dupuis and Veissière 2022; 2022; Johns 2022; Kirlić et al 2025; Pedersen and Steglich-Petersen, n.d.) and reducing their ability to recognize potentially harmful situations (Barber and Dike 2023). The combination of heightened trust and impaired judgment can lead to over-reliance on or dependency on the practitioner (Barber and Dike 2023)
● Client vulnerability and expectations: Clients seeking psychedelic-assisted therapy often present with pre-existing vulnerabilities, such as mental health conditions or trauma histories (Calder and Hasler 2023). They may also hold unrealistic expectations about the therapeutic process or the role of the practitioner (Calder and Hasler 2023; Collins 2024; Evans et al. 2023; Pilecki et al. 2021). This combination of vulnerability and potentially unrealistic expectations can make clients more susceptible to harm
● Impact on therapeutic alliance: The quality of the therapeutic alliance is a critical factor in PAT outcomes (Garcia-Romeu and Richards 2018; Modlin et al 2023) A strong
therapeutic alliance is characterized by a sense of safety, trust, and collaboration between the patient and therapist and is essential for navigating challenging experiences and making meaning of the psychedelic experience (Garcia-Romeu and Richards 2018; Modlin et al 2023) Conversely, a weaker therapeutic alliance is associated with poorer treatment outcomes (Modlin et al 2023) If a client does not feel safe with the practitioner, they may be less likely to openly share their experiences and insights (Zeller, n d )
● Therapist characteristics: Certain therapist traits, such as being rigid, critical, distant, or distracted, can negatively impact the therapeutic alliance (Garcia-Romeu and Richards 2018) Therapists need to be open, empathetic, and non-judgmental to avoid dominating the client's experience or imposing their own beliefs (Zeller, n d ) The therapist's worldview and intersectional identities also shape the therapy process (O’Donnell, Grigsby, and Grob 2025)
● Amplified transference and countertransference: Psychedelics can amplify transference and projection. Clients may project strong feelings, such as intense love, idealization, or even fear, onto the therapist, viewing them as parental figures, angels, demons, or deities (Evans & Holcomb, 2025)
● Existing power imbalances in the therapeutic relationship may be amplified, increasing the risk of boundary violations (Dupuis and Veissière 2022; Pedersen and Steglich-Petersen, n.d.; Calder and Hasler 2023; Neitzke-Spruill et al. 2024; Spriggs et al. 2023; Muthukumaraswamy, Forsyth, and Sumner 2022; Spriggs et al. 2023). Practitioners' own unresolved issues and biases (countertransference) can also negatively influence the therapeutic process and potentially harm clients (Gorman et al 2021 )
● Co-dependency and abuse of authority: Individuals in positions of authority within psychedelic communities, such as shamans, guides, or therapists, may exploit the vulnerability of participants seeking guidance and healing This can lead to power imbalances, emotional manipulation, and even instances of sexual abuse (Argyri et al 2024; 2024).
Boundary Violations and Ethical Lapses
● Sexual misconduct: The increased suggestibility and vulnerability induced by psychedelics creates the risk of sexual boundary violations, including sexual touching and rape (Barber and Dike 2023; Holoyda 2023; Kruger et al 2024; Holoyda 2023) In one survey, 8% of naturalistic users reported knowing someone who was the victim of inappropriate sexual contact by a psychedelic sitter, guide, or practitioner (Kruger et al. 2024). Of those who reported sexual misconduct, 46.3% of the perpetrators were underground sitters or guides (Kruger et al. 2024).
● Financial exploitation: Practitioners may exploit vulnerable clients financially (Evans & Holcomb, 2025)
● Emotional abuse: Emotional manipulation or abuse can occur when practitioners take advantage of the power imbalances inherent in the therapist-client relationship, which
can be amplified during psychedelic states (Muthukumaraswamy, Forsyth, and Sumner 2022).
● Lack of clear boundaries and ethical guidelines: Unclear boundaries surrounding touch, intimacy, and multiple relationships can create ambiguity and increase the risk of exploitation (Fonzo, Nemeroff, and Kalin 2025; Marcus 2023; Spriggs et al. 2023; Devenot et al. 2022; 2022; Edelsohn and Sisti 2023; Pilecki et al. 2021; 2021; Wells, Fernandes, and Reynolds 2024) The lack of standardized ethical guidelines for psychedelic therapy, especially in non-research settings, further complicates matters (Fonzo, Nemeroff, and Kalin 2025; Dupuis 2021; Neitzke-Spruill et al 2024; Spriggs et al 2023; Devenot et al 2022; Marcus 2023) For example, some practitioners may believe that traditional therapeutic boundaries do not apply in psychedelic work, potentially exposing clients to harm
● Failure to maintain professional boundaries: Therapists must maintain clear boundaries to avoid dual relationships or other forms of exploitation (Rosa et al. 2022; Kious, Schwartz, and Lewis 2023). A lack of boundaries may be especially harmful to a patient who has experienced previous boundary violations (Modlin et al 2024) One study reported a case where an MDMA-assisted psychotherapy study participant developed a dependency on the therapist and moved in with them (Kruger et al 2024)
Practitioner Competence and Training
● Inadequate practitioner training/experience: Lack of adequate training and experience in psychedelic therapy can lead to adverse events and inadequate responses to challenging experiences (Wilson-Poe et al 2024) Practitioners lacking adequate training in psychedelic-assisted therapy may not possess the necessary skills to support clients safely through challenging experiences or to navigate complex ethical dilemmas(Calder and Hasler 2023; Fonzo, Nemeroff, and Kalin 2025; Neitzke-Spruill et al. 2024; Spriggs et al. 2023; Kelly et al. 2023; Peterson et al. 2023; Wilson-Poe et al. 2024) The training of therapists should include education on patient hyper-suggestibility, enhanced transference and projection, therapist ego-inflation and countertransference, and the risk of undue influence Improper vetting and training of providers can lead to potential harm from a practitioner(Kruger et al. 2024).
● Lack of self-awareness: Therapists who are not self-aware of their own motives and biases may inadvertently harm clients. Therapists need to reflect on their personal motivations and potential countertransference issues (Evans & Holcomb, 2025)
● Inappropriate self-disclosure: Therapist disclosure of personal psychedelic use could potentially generate unhelpful transference and countertransference, thereby undermining the therapeutic process (Wilson-Poe et al. 2024).
Belief Shaping and Epistemic Harm
● Imposition of beliefs: Practitioners may inadvertently impose their beliefs or interpretations onto clients (Cheung et al , n d ; Zeller, n d ) who may be more susceptible to the suggestions and frameworks of others (Cheung et al , n d ) This can
lead to a form of epistemic domination, where patients' unique perspectives are marginalized or dismissed (Zeller, n.d.).
● False insights: Practitioners need to be careful not to over emphasize the value of “insights” made during the experience Those insights, while perhaps feeling profound in the moment, may lack factual truth and may ultimately solidify into distorted beliefs (Zeller, n d )
● Undermining patient autonomy: If clinicians interpret challenging experiences for the client, they may be undermining patient decision-making and autonomy (Palitsky et al., n.d.).
● Emphasis on specific outcomes: Emphasis on specific outcomes, such as mystical-type experiences, can create pressure on the participant, which may negatively impact the experience(McGovern et al 2024)
● Psychological distress and trauma: The intense emotional experiences induced by psychedelics can be overwhelming, leading to psychological distress, anxiety, panic, and even trauma (Breeksema et al 2022; 2022; 2024; Deane 2020; Evans et al 2023; Ghaznavi et al. 2025; Gorman et al. 2021; 2021; Hendricks et al. 2022; Kočárová, Horáček, and Carhart-Harris 2021; Palitsky et al., n.d.; Soares, Leite, and Pinto 2023; Van Elk and Fried 2023; Walther and van Schie 2024) Practitioners may unintentionally exacerbate these challenges through inadequate support, inappropriate interventions, or by imposing their own beliefs or interpretations onto clients' experiences For example, practitioners might pathologize challenging experiences, leading to increased distress and self-blame in clients(Palitsky et al., n.d.).
● Spiritual and existential crises: Psychedelic experiences can trigger profound spiritual and existential crises, leading to confusion, disorientation, and difficulty integrating these experiences into daily life(Breeksema et al. 2022; 2022; Evans et al. 2023; Van Elk and Fried 2023; Argyri et al 2024; Palitsky et al , n d ) Practitioners lacking sensitivity or training in these areas may mishandle these crises, potentially leading to further distress and difficulty for clients
● Dependence and attachment issues: The intense emotional connection that can develop between practitioners and clients during psychedelic experiences can lead to unhealthy dependence and attachment (Gorman et al 2021; Pronovost-Morgan, Hartogsohn, and Ramaekers 2023) This can complicate the therapeutic process and potentially make it difficult for clients to develop independence and autonomy.
4.3 Interpersonal Risk Factors
The interpersonal and social dynamics in group settings can significantly impact the safety and outcomes of psychedelic experiences This section breaks down the risk factors and adverse events related to group dynamics.
Relationship Tensions and Social Support
● Pre-existing tensions: Using psychedelics in the presence of individuals with whom there is pre-existing tension can contribute to negative outcomes. One study found that
33% of participants who had negative experiences took psychedelics with someone they had relationship issues with (Bremler et al. 2023). Some people take psychedelics with the intention of working through relationship issues, which can be problematic (Bremler et al 2023) 35% of those with extended difficulties used psychedelics with friends, partners or groups of friends 18 9% used them alone (Evans et al 2023) Only 12% of people with extended difficulties took psychedelics at parties, compared to 3% of all users(Evans et al 2023)
● Lack of social support: The absence of social support and safety measures in a group can increase the risk of challenging experiences and the need for medical attention (Golden et al 2022; Marazziti et al 2024) Conversely, positive social relationships and a sense of support can increase the likelihood of positive experiences(Golden et al 2022)
● Importance of peer support: Many first-time users rely on peers and friends for information and harm-reduction advice (Baxter et al 2024) Having a person with prior experience present during a session is common, and first-time users often disclose their inexperience, suggesting a desire for support (Baxter et al. 2024). Lower levels of trust in those present may correlate with more negative outcomes(Baxter et al 2024)
Group Dynamics and Influence
● Group composition and dynamics: The "psychosocial matrix" of a group, including interactions and power dynamics between the participant and guide, teacher, or other participants, can influence outcomes (Palitsky et al., n.d.). Certain group dynamics, such as power imbalances, unresolved conflicts, or a lack of trust, can create tension and potentially trigger challenging experiences for other people in the group (Argyri et al 2024; Barber, Gardner, and Carter 2024; Bremler et al 2023; Haden, Emerson, and Tupper 2016; Spriggs et al. 2023).
● Suggestibility and belief-shaping: Psychedelics can increase suggestibility, making individuals more vulnerable to the influence of others (Cheung et al., n.d.; Robinson et al 2024; Kruger et al 2024; Bremler et al 2023) This can lead to the adoption of both healthy and harmful, unwarranted, or unsustainable beliefs (Cheung et al , n d; Robinson et al 2024)
● Cultic dynamics: Psychedelic experiences can promote group cohesion and identity, which may amplify cultic dynamics (Cheung et al., n.d.). These dynamics can create conditions where harm and misconduct are more likely to occur and go unreported (Evans & Holcomb, 2025)
● Lack of shared intentions and expectations: When participants have differing motivations, expectations, or understandings of the psychedelic experience, conflicts can arise (Barber, Gardner, and Carter 2024; Cheung et al , n d ) Some participants might approach the experience with a therapeutic mindset while others seek recreational or spiritual exploration, potentially leading to misunderstandings and negative interactions (Barber, Gardner, and Carter 2024)
● Inadequate screening and preparation: Insufficient screening for individual risk factors can lead to the inclusion of individuals who are more likely to experience adverse effects
within a group context (Barber, Gardner, and Carter 2024; Haden, Emerson, and Tupper 2016; Barber, Gardner, and Carter 2024; Calder and Hasler 2023) A lack of proper preparation regarding group dynamics and potential challenges can leave participants ill-equipped to navigate interpersonal difficulties during the psychedelic experience. (Haden, Emerson, and Tupper 2016; Barber, Gardner, and Carter 2024; Calder and Hasler 2023).
Integration and Peer Support Groups
● Insufficient facilitation and support: The absence of skilled facilitators or inadequate support during and after the psychedelic experience can exacerbate interpersonal challenges within the group (Bremler et al. 2023; Haden, Emerson, and Tupper 2016; Barber, Gardner, and Carter 2024). Participants might lack the guidance and emotional support needed to navigate difficult emotions or conflicts that may arise, potentially leading to negative outcomes (Bremler et al 2023; Haden, Emerson, and Tupper 2016; Barber, Gardner, and Carter 2024).
● Need for community: Feelings of isolation and disconnection are common after psychedelic use, creating a demand for integration groups(Cheung et al., n.d.; Robinson et al. 2024). These feelings can be exacerbated by the ineffability of the experience, legal restrictions on psychedelic use, and stigma (Cheung et al , n d )
● Benefits of integration groups: Integration groups and peer support can address loneliness, provide a supportive community, and help individuals make sense of their experiences (Cheung et al , n d ) Sharing circles can be important for integration (Cheung et al., n.d.).
● Risks of integration groups: Integration groups may expose individuals to harmful or misinformed beliefs (Cheung et al , n d ) and amplify cult-like social dynamics (Cheung et al , n d ) In addition, many integration groups are not led by clinicians and exist in unregulated settings, possibly elevating the risk of harm (Cheung et al , n d )
Sexual Misconduct
● Increased vulnerability: The suggestibility and vulnerability induced by psychedelics can make individuals vulnerable to therapist abuse and sexual misconduct (Kruger et al 2024) One study found that 7 9% of participants reported knowing someone who experienced sexual violations in the context of psychedelic use, often by underground sitters or guides (Kruger et al. 2024). Further research is required in order to compare the statistical prevalence of sexual transgressions in psychedelic-assisted therapy versus other helping professions.
Adverse Events
● Negative Emotional Contagion: The intense emotional states induced by psychedelics can be contagious within a group A single individual's negative experience, such as
anxiety, panic, or paranoia, can spread to others, creating a cascade of challenging experiences.(Bremler et al. 2023; Breeksema et al. 2022)
● Interpersonal Conflicts and Boundary Violations: The heightened emotional vulnerability during psychedelic experiences can increase the risk of interpersonal conflicts and boundary violations within a group setting (Argyri et al 2024; Bremler et al 2023; Spriggs et al 2023; Calder and Hasler 2023; Villiger 2024) Pre-existing power imbalances or tensions can be exacerbated, potentially leading to manipulation, abuse, or other forms of harm (Argyri et al 2024; Spriggs et al 2023; Calder and Hasler 2023)For example, individuals claiming authority within the psychedelic space might exploit the vulnerability of others.(Argyri et al. 2024)
● Disrupted Group Cohesion and Trust: Challenging experiences within the group, especially if mishandled, can erode trust and cohesion among participants (Spriggs et al. 2023)This can lead to feelings of isolation, alienation, and difficulty integrating the experience The breakdown of group support can hinder the potential therapeutic benefits of shared experience and community.(Spriggs et al. 2023)
● Social Withdrawal and Isolation: In some cases, negative experiences within a group setting can lead to social withdrawal and isolation Participants might become disillusioned with psychedelic communities or develop anxieties about participating in future group experiences (Engel, Thal, and Bright 2022a; Palitsky et al , n d )
4.4 Setting-Specific Risk Factors
The effects of psychedelics are highly dependent on the context in which they are taken (Bremler et al 2023; Palitsky et al , n d ) "Set and setting" are critical elements of this context "Set" refers to the individual's mindset and psychological preparation, while "setting" encompasses the physical and social environment in which the experience takes place (Robin L Carhart-Harris et al 2018; 2018; Gashi et al , 2021; Johnstad 2021; Martin and Sterzer 2022) A poor combination of set and setting can lead to challenging experiences (Bremler et al. 2023; Golden et al 2022; Rocha et al 2023; Baxter et al 2024; Gandy et al 2020; Baumeister, Tojo, and Tracy 2015; Hirschfeld et al 2021; Breeksema et al 2022; Izmi, Carhart-Harris, and Kettner 2024; Breeksema et al. 2022; Kopra et al. 2022; Aday et al. 2020; Davis et al., n.d.; Earleywine et al 2024) or “bad trips," characterized by anxiety, confusion, dysphoria, and sometimes paranoia (Johnson et al. 2019; Barrett et al. 2016). This section outlines general risks associated with setting for all psychedelic substances
All Settings
● Environmental and safety hazards: This encompasses factors like unsafe or uncomfortable physical surroundings, the risk of accidents or injury, lack of access to medical care in case of emergency, and exposure to extreme weather conditions (Gashi, Sandberg, and Pedersen 2021; Johnstad 2021; Aday, Bloesch, and Davoli 2020; Bălăeţ 2022a; Bremler et al 2023; Haden, Emerson, and Tupper 2016; 2016; Hirschfeld et al 2021; Pilecki et al. 2021).
● Unsafe, uncomfortable, or unsupportive settings: Negative outcomes are more likely to occur in unsafe, uncomfortable, unsupportive, or unfamiliar settings (Bremler et al. 2023; Kopra et al 2022; Morton et al 2023; Davis et al , n d ; Baxter et al 2024; Ramaekers, Reckweg, and Mason 2025a; Hirschfeld et al. 2021; Campo and Yali 2024; Haijen et al 2018; Irvine and Luke 2022; Palmer and Maynard 2022; Pilecki et al 2021) This includes environments that are stressful, chaotic, or lacking in proper medical or psychological support (Bremler et al. 2023; Johnstad, 2021; Orłowski et al. 2022). For example, misinformation about the dangers of LSD circulated in the media during the 1960s may have contributed to more “bad trips” through negatively affecting the mindsets of users (Kopra et al. 2022). More positive portrayals of psychedelics in media may lead to less challenging experiences (Kopra et al 2022)
● Unforeseen interruptions or intrusions: Disturbances or unexpected events during a psychedelic experience can be highly destabilizing and potentially trigger anxiety, paranoia, or challenging emotional responses (Haden, Emerson, and Tupper 2016; Pilecki et al. 2021). This could include unexpected visits from strangers, loud noises, or changes in the environment
Clinical and Research Settings
While these are often considered the safest contexts, risks still exist These are often mitigated by strict protocols and procedures (Johnson et al 2019; Garcia-Romeu and Richards 2018; Bender and Hellerstein 2022; Golden et al 2022; Gukasyan et al 2022; Evens et al 2023; Rosenblat et al 2023; Romeo et al 2024; Ehrenkranz et al 2024; Henningfield et al 2023)
● Artificiality of the setting: The controlled and sterile environment of a clinical or research setting can sometimes feel impersonal or restrictive, potentially hindering participants' ability to fully surrender to the experience. The presence of medical equipment or procedures can also trigger anxiety or discomfort for some individuals (Gashi, Sandberg, and Pedersen 2021; Bălăeţ 2022a; Bremler et al 2023; Hartogsohn 2017; Holze et al. 2022; Garcia-Romeu and Richards 2018).
● Influence of research protocols: The structured nature of research protocols, including specific dosages, timings, and interactions with researchers, can sometimes limit the flexibility and spontaneity that may be beneficial for certain individuals. This can create a sense of pressure or expectation that might interfere with the natural unfolding of the experience (Hartogsohn 2017)
● Potential for manipulation: Vulnerable states induced by psychedelics could expose participants to undue influence or manipulation from facilitators (Neitzke-Spruill et al 2024)
● Suicidality risk: While rare, some clinical trials have reported cases of suicidality, even with low doses, although this may also have links to factors outside of the psychedelic treatment itself (Rosenblat et al. 2023). In one study, rates of suicidal behavior were higher in the treatment groups (10 and 25 mg) compared to the control group (1 mg) in a recent clinical trial of psilocybin for treatment-resistant depression, though these same treatment groups also experienced robust antidepressant effects (Kruger et al 2024)
Regulated Retreats and Religious Contexts:
● Lack of screening: Some retreats or religious groups may lack thorough screening processes, increasing risks for vulnerable individuals (Johnson et al 2019; Rosenblat et al. 2023; Honk et al. 2024).
● Group dynamics and leadership: The dynamics within group settings, particularly those with strong leadership figures or hierarchical structures, can create vulnerabilities for participants. Power imbalances, pressure to conform to group norms, and potential manipulation by leaders are risks to consider (Haden, Emerson, and Tupper 2016; Aday et al. 2021; Dupuis and Veissière 2022; Haijen et al. 2018). Group settings may pressure individuals to adhere to certain beliefs or practices, especially given the suggestibility induced by psychedelics (Pontual et al 2021; Golden et al 2022)
● Dogmatic beliefs and practices: Rigid beliefs or practices, especially those that discourage critical thinking or individual exploration, can potentially limit the autonomy and freedom of participants This can create a sense of pressure to conform to a particular ideology, potentially leading to cognitive dissonance or feelings of invalidation (Aday et al 2021; Dupuis and Veissière 2022; Byrne et al 2023)
● Cultic dynamics: Psychedelic use in groups can sometimes amplify cultic dynamics due to shared experiences and heightened suggestibility (Golden et al. 2022).
● Variable practices: There can be variability in the quality and safety of practices depending on the specific retreat or religious group (Pontual et al 2021)
● Unqualified facilitators: Many groups are not led by clinicians and exist in unregulated settings, possibly elevating the risk of harm (Holoyda 2023; Bender and Hellerstein 2022).
● Inadequate Integration: Integration support after the experience can be variable or lacking in some contexts (Garcia-Romeu and Richards 2018; Aday et al 2020)
● Overemphasis on spiritual or transformative aspects: Some retreat or religious contexts may overemphasize spiritual or transformative aspects, and downplay potential risks (Bremler et al. 2023; Evens et al. 2023; Ehrenkranz et al. 2024; Palitsky et al., n.d.)
Underground/Unregulated, Supervised Settings:
● Lack of screening: There may be no formal process to screen participants for contraindications(Aday et al. 2020; Rosenblat et al. 2023).
● Variability in practitioner skills and ethics: In unregulated settings, the skills, experience, and ethical standards of practitioners can vary widely, leading to inconsistencies in the quality of care and support provided The absence of standardized training or oversight increases the risk of inadequate support, boundary violations, or other forms of harm (Gashi, Sandberg, and Pedersen 2021; Pilecki et al. 2021;Garcia-Romeu and Richards 2018; Aday et al 2020) It also means that guides may not be able to manage challenging experiences or emergencies (Baxter et al 2024; Kopra et al. 2025).
● Lack of accountability and legal recourse: In the absence of regulation, there may be limited accountability for practitioners and few avenues for legal recourse if adverse
events occur This can leave participants feeling vulnerable and disempowered (Gashi, Sandberg, and Pedersen 2021; Pilecki et al. 2021;Kopra et al. 2025; Barber and Dike 2023)
● Risk of adulteration: There is a greater risk of taking adulterated substances or misidentified drugs (Barber and Dike 2023) in these settings. This could be especially true of MDMA, where contamination from fentanyl and other opioids is a significant concern (Rajwani 2022)
Unsupervised Recreational Use:
● Unpredictable environments and social dynamics: Parties, festivals, and other social settings present unpredictable environments with varying levels of stimulation, social interactions, and potential distractions. The lack of control over these factors can increase the risk of anxiety, sensory overload, and challenging interpersonal experiences (Gashi, Sandberg, and Pedersen 2021; Bălăeţ 2022a; Bremler et al 2023; Haden, Emerson, and Tupper 2016; Pilecki et al. 2021; Johnstad 2021; Palmer and Maynard 2022; Barnett and Greer 2021; Bodnár and Kakuk 2019)
● Lack of support and guidance: Individuals using psychedelics in unsupervised settings may not have access to support or guidance if they encounter challenging experiences. This can increase the likelihood of a difficult or even traumatic experience (Carbonaro et al. 2016; Johnson et al. 2018; Baxter et al., 2024; Bremler et al., 2023) and lead to feelings of isolation, panic, confusion, and difficulty navigating intense emotional states (Gashi, Sandberg, and Pedersen 2021; Pilecki et al 2021; Bremler et al , 2023) Individuals in these settings may be less well-prepared for these difficult experiences, leading to a decrease in well-being and an increase in risk-taking behavior(Holoyda 2023; Aday et al 2020)
● Accidents and injuries: A lack of supervision, altered perception, and impaired judgment increase the risk of accidents and injuries (Johnson et al. 2019).
● Higher rates of medical emergencies: These settings are associated with higher rates of emergency room visits due to psychological distress, panic, or inability to control the effects(Bender and Hellerstein 2022; Canady 2023).
● Higher risk of polydrug use: Recreational settings often involve a greater risk of combining psychedelics with other substances (Kopra et al 2025; Barber and Dike 2023)
● Delayed help or lack of help: Individuals may have limited access to medical or psychological help in case of adverse reactions (Kopra et al. 2025; Palitsky et al., n.d.).
Research Risks Limiting Safety and Public Health Knowledge
● Functional unblinding: In clinical trials, it can be difficult to maintain blinding due to the noticeable effects of psychedelics, which can introduce bias in results (Gukasyan et al 2022)
● Adverse Event Underreporting: There may be underreporting of adverse events, due to various reasons such as a tendency to emphasize the positive results(Romeo et al. 2024; Ehrenkranz et al. 2024).
● Expectancy Effects: Participants' high expectations for positive outcomes may lead to increased psychological distress if the experience does not meet those expectations (Romeo et al 2024) This may also be related to an over-emphasis on positive outcomes in the reporting of psychedelic research (Bremler et al 2023; Evens et al 2023; Ehrenkranz et al. 2024; Palitsky et al., n.d.).
● Challenges in managing difficult experiences: Despite supportive settings, there can be a lack of detailed reporting on how anxious or psychotic states and challenging experiences are managed, which is important for formulating safety protocols (Rossi et al 2022)
● Lack of standardization: A lack of standardized protocols for reporting adverse events and a tendency to focus only on psychological issues (rather than social, cultural, or other contextual risk factors) can lead to gaps in knowledge (Golden et al. 2022).
4.5 Risk Factors Related to Preparation and Integration
Preparation and integration sessions are essential components of a well-structured psychedelic experience and can help support successful outcomes This includes pre-session discussions about potential drug effects, and post-session integration to help make meaning of the experience (Neitzke-Spruill et al. 2024). Individuals using psychedelics, particularly in non-clinical settings, may face risks during the preparation and integration phases that can contribute to adverse events, described below
Preparation
● Inadequate screening: Insufficient screening of participants can lead to adverse outcomes (Garcia-Romeu and Richards 2018; Barber and Dike 2023). A personal or family history of psychosis, mania, hypomania, or violence are often exclusion criteria in clinical trials, due to a theoretical risk of increased vulnerability to adverse reactions (Rosenblat et al 2023; Barber and Dike 2023) Additionally, certain personality types and psychiatric disorders could be contraindications for psychedelic use (Bremler et al 2023)
● Inadequate education and information: Insufficient knowledge about the effects of psychedelics, including potential psychological and physical risks, can lead to unrealistic expectations and poor decision-making Without proper information, individuals may underestimate the intensity of the experience, leading to anxiety or panic during the session (Anderson et al 2019; Hirschfeld et al 2021)
● Insufficient psychological preparation: Lack of preparation to address personal vulnerabilities, trauma history, or emotional regulation skills can make individuals more susceptible to challenging experiences (Aday et al 2020; Breeksema et al 2022), and, in general, people who feel unprepared for a session report more adverse outcomes (Davis et al , n d ) Preparation typically includes a life review to build rapport and
understand major life events, potential traumas, and relationships (Garcia-Romeu and Richards 2018). Psychedelics can intensify pre-existing psychological issues, potentially leading to emotional distress, trauma reactivation, or difficulty coping with intense emotions (Barrett, Johnson, and Griffiths 2017; 2017; Breeksema et al. 2022; Ghaznavi et al 2025; Gorman et al 2021) Many people may expect only positive outcomes from psychedelics, which can lead to disappointment if the experience is challenging (Evans et al. 2023; Palitsky et al., n.d.). A lack of detailed discussion about potential drug effects and the possibility of a challenging experience can also increase risks (Garcia-Romeu and Richards 2018)
● Unclear intentions and goals: Individuals lacking clear intentions for their psychedelic experience may be more prone to confusion, disorientation, and difficulty integrating the experience afterward A lack of purpose can make it challenging to make sense of the experience and apply insights gained during the session (Campo and Yali 2024; Haijen et al 2018)
● Neglecting set and setting considerations: For an extensive discussion of these, please see section 5 4 above
Integration
● Lack of integration practices: A lack of proper integration of the psychedelic experience can lead to adverse events (Aday et al. 2020; Forstmann and Sagioglou 2021; Zeller, n d ) Integration helps individuals process and make sense of their experiences, and a lack of it can lead to extended difficulties (Robinson et al 2024; Evans et al. 2023; Piercey et al. 2024). Failing to engage in practices that support integration, such as journaling, meditation, art therapy, or connecting with nature, can limit the long-term benefits of the psychedelic experience. These practices help to solidify insights, cultivate self-awareness, and promote emotional regulation, ultimately facilitating a smoother integration process (Bathje, Majeski, and Kudowor 2022; Evans et al. 2023; O. Robinson et al. 2024).
● Lack of support and guidance: Without adequate support from therapists, peers, or integration groups, individuals may struggle to process and make sense of their psychedelic experiences, potentially leading to confusion, anxiety, or difficulty integrating insights into their lives (Bathje, Majeski, and Kudowor 2022; Evans et al 2023; 2023; O Robinson et al 2024) Social support, particularly from peers who share similar experiences, is crucial for managing post-psychedelic difficulties (Robinson et al. 2024; Davis et al , n d ) A lack of support can exacerbate negative feelings (Cheung et al , n.d.).
● Insufficient time for processing and reflection: Rushing back into daily routines without sufficient time for reflection and integration can hinder the processing of insights and emotional experiences. This can lead to feelings of overwhelm, difficulty applying lessons learned, or the re-emergence of pre-existing psychological challenges (Bathje, Majeski, and Kudowor 2022; Evans et al 2023)
● Dismissing or minimizing challenging experiences: Attempting to ignore or suppress difficult or distressing aspects of the psychedelic experience can prevent individuals from
fully processing and integrating these experiences This can lead to unresolved emotional issues, lingering psychological distress, or the perpetuation of unhealthy coping mechanisms (Davis et al 2022; Palitsky et al , n d )
● Belief shaping and misinformation: Due to the suggestibility-enhancing effects of psychedelics, individuals may be more vulnerable to adopting maladaptive or poorly formed beliefs if not supported with effective integration (Zeller, n d ; Robinson et al 2024; Cheung et al., n.d.). Integration groups may expose individuals to misinformation, misinterpreted scientific information, or unsafe coping strategies (Cheung et al , n d ) Integration groups can sometimes exhibit cultic social dynamics, which can increase vulnerability to undue influence (Cheung et al., n.d.). Shared experiences within groups can amplify group cohesion to a destructive degree (Cheung et al , n d )
● Absence of self-soothing guidance: Given the prevalence of anxiety and fear following psychedelic use, a lack of guidance on methods for self-soothing may exacerbate adverse outcomes (Evans et al 2023)
4.6 Cultural and Spiritual Risk Factors
Psychedelics can have profound effects on individuals’ cultural and spiritual views; however, these effects come with certain risks This section outlines cultural and spiritual risk factors that can lead to adverse events and harms associated with psychedelic use. Keep in mind that these factors are often intertwined with an individual's "set" (mindset and expectations) and "setting" (environment), shaping how they experience and interpret their psychedelic journey (Bremler et al. 2023). A misalignment between a person's spiritual beliefs and the setting of the psychedelic experience can cause distress (Bremler et al 2023) Please refer to section 4 4 above for more information about this topic.
Cultural Risk Factors
● Lack of cultural context and understanding: Psychedelic experiences are shaped by cultural frameworks and beliefs, and neglecting these contexts can lead to confusion, disorientation, and inappropriate integration (Argyri et al 2024; 2024; 2024; Hartogsohn 2024; Walther and van Schie 2024). As psychedelic medicines are adopted in Western culture, there is a risk that modern medical settings might mimic Indigenous ceremonial practices, which can trivialize the rich traditions that have developed around them (Barber and Dike 2023). Western medical practices should not dictate or devalue non-Western forms of knowledge, including Indigenous Peoples’ sovereignty and rights related to traditional psychedelic use It’s essential to honor the communities that developed principles of psychedelic use over generations and to ensure these communities are not harmed by the commercialization of their traditions This is particularly relevant with plant medicines such as Ayahuasca and peyote, which have a long history of use in Indigenous cultures (“Psychedelic Medicalization, Public Discourse, and the Morality of Ego Dissolution - Alex K Gearin, Neşe Devenot, 2021,” n d ) In Peru, reports indicate negative economic, social, cultural, health, and environmental
impacts from the presence of tourists who may be culturally and linguistically uninformed(Bathje, Majeski, and Kudowor 2022).
● Cultural misinterpretation of experiences: Psychedelic experiences can be deeply influenced by cultural backgrounds (Davis et al. 2024). If interpretations of these experiences conflict with a person’s cultural norms, resources, or global worldview, distress and challenges may result (Palitsky et al , n d ) For example, a person from a culture that stigmatizes altered states of consciousness may struggle to integrate a psychedelic experience that involves such states, and may misinterpret it as a sign of mental instability or spiritual danger One study showed that personal meaning derived from psychedelic experiences tended to be lower among those who identified as Hispanic, which suggests that cultural or spiritual beliefs may affect the perceived meaning (Goldy et al, 2024)
● Lack of culturally competent care: Different cultural groups may have distinct experiences with psychedelics and may require different coping techniques, highlighting the need for culturally tailored support (Evans et al 2023) In clinical settings, the exclusion of BIPOC (Black, Indigenous, and People of Color) people from psychedelic trials is a significant issue This lack of diversity means that treatment approaches may not address the unique stressors and cultural contexts faced by these communities, making the intervention less relevant or even insensitive. (Haft et al., 2025) This can result in reduced efficacy, mistrust, or negative outcomes for individuals from these backgrounds For example, historical injustices in psychedelic research and the ongoing criminalization of psychedelics may affect the perspectives and outcomes for people from marginalized groups A previous review found that between 1993 and 2017, 82 3% of participants in clinical psychedelic studies identified as non-Hispanic White. This demonstrates the critical issue of underrepresentation of diverse populations in clinical research (Fogg et al , 2021)
● Racial and ethnic disparities: Experiences of racism and racial trauma can have effects on the psychedelic experience itself as well as interactions with therapists (Rajwani 2022) Systemic oppression and racial discrimination can alter the nature of the psychedelic experience for racial and ethnic minorities, potentially leading to fewer protective associations between psychedelics and mental health. Drug policies in America are highly racialized, leading to a disproportionate risk of arrest and police violence for racial and ethnic minorities who engage in illicit substance use The history of the war on drugs and the negative stigma associated with it could contribute to a sense of unsafety with psychedelic use In contrast, White participants may experience more ease due to greater cultural exposure to psychedelics, dating back to the 1960s. (Jones, 2023)
● Ceremonial Contexts: While some may view ceremonies as safe spaces, experiences that occur in a ceremonial or ritual context can sometimes be associated with negative effects. For example, the use of psychedelics in a ceremony may increase the likelihood of challenging experiences Conversely, one study found that psychological insight was higher among individuals whose experience occurred in a ceremony or ritual context (Goldy et al, 2024)
Spiritual Risk Factors
● Spiritual struggles: Psychedelic experiences can trigger or exacerbate religious and spiritual struggles, such as distressing appraisals and cognitions associated with one’s religious or spiritual worldview (Palitsky et al , 2024) In other words, they can cause an ontological shock, which refers to a profound and disorienting experience of encountering radically different ways of perceiving reality This can cause confusion and distress, especially in individuals who do not have a spiritual or philosophical framework to make sense of the experience. These struggles can be associated with poorer psychosocial outcomes (Robinson et al 2024, Palitsky et al , 2024)
● Clashing with pre-existing beliefs: Psychedelics can trigger profound alterations in consciousness and challenge existing beliefs about reality, the self, and spirituality (Anderson et al. 2019; Hirschfeld et al. 2021). This can be especially difficult for individuals with strong pre-existing religious, spiritual, or philosophical beliefs, leading to cognitive dissonance, existential distress, or even a sense of spiritual crisis.
● Spiritual imposition: There is an ethical risk of imposing spiritual or religious beliefs on individuals undergoing psychedelic-assisted therapy (Palitsky et al , n d ) Determining the line between spiritually responsive care and spiritual imposition is critical for ensuring that the therapeutic process remains respectful and culturally appropriate (Palitsky et al , n.d.).
● Negative spiritual appraisals: If an individual’s spiritual beliefs or their interpretation of a psychedelic experience is dismissed or appropriated by others, it can be harmful and delay recovery from adverse effects (Palitsky et al , n d ) However, spiritual appraisals that are congruent with the experiencer’s beliefs can be helpful in recovery(Palitsky et al , n d )
● Spiritual narcissism and bypassing: Some individuals within psychedelic communities may develop a sense of spiritual superiority or use psychedelics to avoid personal growth and emotional work (“spiritual bypassing”) This can lead to a superficial understanding of spiritual concepts, a lack of genuine self-awareness, and potentially harmful behaviors (Argyri et al 2024)
● Over-reliance on psychedelics for spiritual growth: Attributing all spiritual growth and insight solely to the effects of psychedelics can hinder genuine personal development and integration Individuals may neglect other practices that support well-being, such as meditation, self-reflection, and community involvement (Palitsky et al , 2024)
4.7 Legal Context
The legal status of psychedelics and various regulatory frameworks significantly contribute to adverse events and harms by promoting a dangerous, unregulated market, hindering research, creating access barriers, and creating challenges in providing ethical and informed care (Davis et al , n d ; Rajwani 2022) These issues stem from the conflict between the current prohibitive
legal landscape, the increasing interest in therapeutic and recreational use, and the challenges of regulating substances with such potent and variable effects.
Impact of Illegal Status and Prohibition
● Lack of quality control and adulteration: The primary harm stemming from the illegal status of psychedelics is the absence of quality control (Barber and Dike 2023; Kopra et al. 2025). In unregulated markets, substances sold as psychedelics may be adulterated with other, more dangerous compounds (Rajwani 2022; Barber and Dike 2023; Kopra et al. 2025), increasing the risk of toxicity and unpredictable adverse reactions (Barber and Dike 2023; Elsey 2017a; Haden, Emerson, and Tupper 2016) In addition, "copycat" substances are sometimes produced to circumvent laws, and these may have significantly different risk profiles compared to known psychedelics (Elsey 2017a)
● Unsafe acquisition: The illegal market for psychedelics exposes individuals to risks during procurement, including violence, intimidation, theft, and contact with criminal organizations (Rajwani 2022; Barber and Dike 2023), increasing the likelihood of experiencing distress or harm before the psychedelic experience even begins
● Lack of access to safe settings and support: Because of legal constraints, individuals often use psychedelics in unsupervised, non-clinical settings, increasing the risk of adverse outcomes (Bender and Hellerstein 2022; Hoener et al. 2024; Honk et al. 2024). These settings often lack the structure and support that could mitigate challenging experiences (Evens et al. 2023; Aday et al. 2020). In a non-therapeutic environment, psychedelics are more likely to induce negative effects (Hoener et al 2024)
● Reluctance to seek help: Because of the illegal nature of psychedelic use, individuals experiencing adverse effects may be hesitant to seek medical or psychological assistance, fearing legal repercussions (Freitas et al. 2024; Palitsky et al., n.d.). In addition, individuals may be hesitant to disclose psychedelic use to healthcare professionals, hindering proper medical assessment and intervention (Wells, Fernandes, and Reynolds 2024) They may rely on anecdotal experiences or unreliable online sources, leading to poor decision-making and unsafe practices (Elsey 2017a)
● Limited research: The classification of psychedelics as Schedule I drugs at the federal level in the U.S. imposes a barrier to obtaining robust research evidence regarding their effectiveness and safety profile (Rekatsina et al. 2022; Elsey 2017a). he few labs that can conduct research face stringent and costly standards (Elsey 2017a). This slows progress in understanding the clinical applications of psychedelics and developing safe protocols (Okano et al 2022; Gukasyan et al 2022; Wells, Fernandes, and Reynolds 2024)
● Malpractice risks for psychiatrists: Psychiatrists who choose to provide psychedelic therapies outside the bounds of research face malpractice risks due to the absence of standards of care, the possibility of causing a negative or harmful experience, and the risk of mistreatment of vulnerable patients There are also risks related to civil litigation including respondeat superior, intentional infliction of emotional distress (IIED), negligent infliction of emotional distress (NIED) and battery (Bremler et al 2023)
● Ethical and medico-legal concerns: The lack of a legal route for routine prescription of psychedelics in many regions creates ethical dilemmas for clinicians. If a patient seeks support for self-sourced, illegal psychedelics, the clinician can’t legally be involved in monitoring dosing sessions, facilitating access, or encouraging use outside of clinical trials (Hoener et al 2024)
Impact of Regulatory Frameworks
● Challenges in Clinical Trials:
○ Blinding issues: Designing clinical trials for psychedelics is challenging due to difficulties in selecting a placebo and managing expectancy effects (Gukasyan et al 2022) The unique subjective experiences induced by psychedelics make it difficult to maintain blinding, which can bias results (Gukasyan et al 2022; Kious, Schwartz, and Lewis 2023).
○ "Set and setting": The influence of "set and setting" (contextual factors) on the efficacy of psychedelics makes it challenging to adhere to the typical drug trial model, which emphasizes a "pure" pharmacological action (Gukasyan et al 2022)
○ Regulatory guidelines: While the EMA (European Medicines Agency) guidelines emphasize the role of psychological support, other regulatory guidelines may not sufficiently address these nuances, hindering the integration of psychedelic therapy. (Swieczkowski et al, 2025, McGuire et al., 2024)
● Access and Equity Concerns:
○ Cost of treatment: If psychedelic therapies become legal, they may be costly, often more costly than illegal options, creating unequal access for those who cannot afford it (Wilson-Poe et al. 2024).
○ Criminalization of Psychedelic Use: Some have concerns that there is a risk that if Indigenous psychedelic practices become medicalized, it could be seen as a form of "colonization" (Kopra et al 2025)
○ Overregulation: While some jurisdictions have relaxed restrictions on psychedelic use, over-regulation brings about issues around bureaucracy, accessibility, individual freedoms, inequity and the aforementioned “colonization” if indigenous use is affected (Kopra et al. 2025).
● Informed Consent Challenges:
○ Complexity of experiences: Psychedelic experiences can be unpredictable and intense, with a wide range of potential outcomes This makes obtaining truly informed consent challenging, as patients may not fully comprehend the range of possible experiences, including negative ones (Barber and Dike 2023; Evans et al. 2023; O’Donnell, Grigsby, and Grob 2025).
○ Heightened expectations: Patients may have inflated expectations about the transformative effects of psychedelics due to positive media portrayals and anecdotal evidence, which can cause distress if their experience does not meet those expectations (Barber and Dike 2023)
● Therapist qualification and training: The lack of clear regulatory frameworks for training and certifying psychedelic therapists creates a risk of unqualified individuals providing treatments, potentially leading to inadequate care and harm (Kruger et al. 2024; Wilson-Poe et al 2024) The question of whether therapists should have personal experience with psychedelics is also being debated, with some advocating that it may be beneficial and others expressing concerns about objectivity (Kious, Schwartz, and Lewis 2023; Wilson-Poe et al 2024)
4.8 Socioeconomic and Equity-Related Risk Factors
Socioeconomic disparities and inequities significantly influence the risks and outcomes of psychedelic use, and racial and ethnic minorities face systemic discrimination and oppression that can influence psychedelic experiences and outcomes (Jones and Nock 2022) As outlined below, limited access to resources, healthcare, and mental health support, compounded by systemic racism and social injustice, has created an environment in which marginalized communities face greater vulnerabilities when engaging in psychedelic substance use
● Disparities in access to psychedelic therapy: These can arise due to high costs and limited insurance coverage (Barber, Gardner, and Carter 2024), making these treatments primarily accessible to affluent individuals These disparities can also significantly impact "set and setting," which play a crucial role in shaping psychedelic experiences (Bălăeţ 2022a; Strickland, Garcia-Romeu, and Johnson, n d ; Viña and Stephens 2023) In addition, geographical concerns about equitable access to psychedelic-assisted therapy (PAP) exist, due to the uneven distribution of providers, legal restrictions, and varying levels of awareness across regions (Rosa et al 2022)
● Higher rates of unsafe use: People with fewer resources might be more prone to using psychedelics in unsafe contexts, such as when they are also using other substances (Kopra et al 2025; Davis et al , n d ) or in uncontrolled environments without proper preparation, supervision, or integration support (Bender and Hellerstein 2022; Davis et al , n d )
● Economic stress and mental health: Socioeconomic stressors such as poverty, unstable housing, and income inequality are associated with increased rates of mental health disorders. These conditions, particularly when unaddressed, can increase vulnerability to adverse psychological reactions when using psychedelics (Bremler et al. 2023) Furthermore, individuals experiencing economic hardship may turn to self-medication with psychedelics due to the lack of affordable and accessible mental health care (Bender and Hellerstein 2022; Davis et al , n d ) A study showed that, in 2020, "overdose death rates increased with increasing county-level income inequality ratios." Among Black persons, overdose death rates were highest in counties with the highest income inequality (46.5 per 100,000 population). (Jegede et al., 2024)
● Disproportionate impact of legal status on marginalized communities: Drug policies in the U S are highly racialized, leading to a disproportionate risk of arrest and police violence for racial and ethnic minorities who use psychedelics (Rajwani 2022; Jones and
Nock 2022) This can create a sense of unsafety with psychedelic use, potentially leading to more adverse outcomes in naturalistic settings (Jones and Nock 2022).
● Stigma and perceived risk: Stigma associated with psychedelic use can disproportionately affect marginalized communities, which are more likely to perceive psychedelics as risky (Barnett et al 2024) This increased perceived risk can be further complicated by factors such as historical trauma, experience of discrimination, and lack of access to culturally competent care. There were clear differences in perceived risk by race, with White respondents and those indicating more than one race having significantly lower perceived risk of LSD than respondents from other groups (Barnett et al. 2024).
● Lack of access to healthcare: Individuals from lower SES backgrounds are more likely to have limited access to medical and mental health services This is particularly important when considering that 2 6% of psychedelic users in non-clinical settings have required professional assistance (medical, psychiatric, or psychological) following use (Palitsky et al., n.d.). In the case of adverse events or long-term negative effects, these individuals may lack access to the support needed for proper assessment, treatment, and follow-up (Hinkle et al 2024; Palitsky et al , n d )
● Mistrust of healthcare systems: Historical injustices have increased marginalized communities’ fear of the healthcare system, which can deter individuals from seeking help or disclosing their psychedelic use. This, in turn, may hinder proper medical assessment and intervention (Spriggs et al. 2023).
● Lack of access to culturally informed therapists and support systems: The absence of culturally sensitive care can lead to misinterpretations of experiences, inadequate integration, and potential harm (Edelsohn and Sisti 2023; Pilecki et al 2021) The historical exploitation of Indigenous knowledge and practices further complicates this issue, creating mistrust and barriers to equitable access.
● Impact of literacy and language barriers: Logistical barriers, including literacy and language, may make it more difficult for individuals with low SES to enroll in studies or understand study procedures (Ching & Kelmendi, 2025; Morales et al , 2022) This can further marginalize already vulnerable populations
● Moderation of therapeutic effects: Race and ethnicity can moderate the associations between psychedelic use and mental health outcomes. For instance, a study found that the protective effects of psychedelic use against serious psychological distress and suicidality were significantly lower for racial and ethnic minority participants than for White participants (Jones and Nock 2022) Similarly, for white participants, MDMA and psilocybin use conferred lowered odds of all distress and suicidality outcomes, but for racial and ethnic minority participants, the associations between psychedelic use and suicidality were far fewer. The impact of discrimination on naturalistic psychedelic use for racial and ethnic minorities may explain why there are fewer protective associations between lifetime psychedelic use and major depressive episodes for racial and ethnic minorities (Jones and Nock 2022)
● Lack of diversity in research: There is a lack of diversity in psychedelic research, which may limit generalizability (Edelsohn and Sisti 2023; Pilecki et al 2021; Spriggs et
al 2023) Many clinical trials use small and homogenous samples, limiting the generalizability of findings (Aday et al. 2020). Samples are often largely white, educated, and middle-aged (Aday et al. 2020). In fact, a review found that between 1993 and 2017, 82 3% of participants in clinical psychedelic studies identified as non-Hispanic White (Michaels et al , 2018) This lack of diversity limits the generalizability of research findings and could lead to treatments that are less effective for, or less accepted by, certain populations (Muthukumaraswamy, Forsyth, and Sumner 2022; Morales et al , 2022). This is particularly relevant because those from marginalized communities experience chronic stress due to their marginalized status. Underrepresentation of diverse populations in clinical trials limits the generalizability of findings and can lead to the development of therapies that are not culturally sensitive or appropriate for all communities This is problematic, because individuals from minoritized demographic backgrounds experience chronic stress due to their marginalized status, and disproportionately bear the burden of moderate to severe mental illness. Treatment approaches that do not acknowledge and address the specific stressors faced by these communities may be perceived as irrelevant or insensitive, thus influencing acceptability
4.9 Contamination and Quality Risk Factors
Illicitly produced substances are at risk for being adulterated with other psychoactive compounds (Barber and Dike 2023) For instance, one study found that 63% of pills sold as MDMA contained MDMA or a related analog, while 29% contained other identifiable drugs (Banta-Green et al, 2005) There are reports of "bad batches" or contaminated supplies circulating in online communities (Ortiz Bernal et al 2022) However, it's difficult to gather data on the prevalence of these, which are typically anecdotal and unconfirmed.
● Lack of testing: There is a lack of access to accurate testing methods for substances purchased on the illicit market Drug test kits are often unreliable and cannot detect all adulterants, accurately measure the amount of drug present, or predict an individual's response to a given drug
● Lack of user awareness: Individuals using self-sourced psychedelics often cannot accurately identify the substance they have procured, increasing the risk of unexpected and potentially harmful effects (Barber and Dike 2023)
● Unpredictable experiences: The quality of the substance can affect the overall experience (Bremler et al 2023) Users are at risk of experiencing more intense, negative, or unexpected psychoactive effects due to impurities and varying dosages (Bremler et al. 2023; Lancelotta and Davis 2020b). Lower quality substances can lead to challenging or negative experiences that may have lasting adverse effects on an individual's mental state (Bremler et al. 2023).
● Increased risk of adverse events: The presence of unknown substances or impurities can cause unexpected adverse reactions, such as nausea, vomiting, seizures, fatigue, hyperthermia, and cardiovascular issues (Dourron et al 2023; Lancelotta and Davis
2020b; Kwaśny, Wilkowska, and Cubała 2024) Unpredictable experiences and negative physical effects may lead to the need for medical intervention (Dourron et al. 2023).
● Long-term health issues: Chronic exposure to unknown substances may cause long-term health complications (Calina, Carvalho, and Oana Docea 2021)
● Specific contaminants:
■ NBOMes are a dangerous class of compounds that have been found in samples sold as LSD or MDMA. These compounds have higher toxicity and may have unpredictable and prolonged effects (Hirschfeld et al 2021).
■ Novel synthetic phenethylamines, such as NBOMes and other substances, can be present in samples, potentially leading to severe adverse reactions, including fatalities (Hirschfeld et al. 2021).
■ Illicitly manufactured LSD can be contaminated with substances that have atropine-like effects, which can contribute to psychotic symptoms (Sabé et al. 2024)
4.10 Adverse Events Associated with All Psychedelic Substances
Adverse effects of individual psychedelic substances will be detailed in the next section This one looks at the adverse effects common to all of them Bear in mind that studies suggest a potential underreporting of adverse events in psychedelic research, due to the absence of systematic assessments (Robinson et al. 2024).
Acute Adverse Effects
● Psychological: Psychedelics can induce psychological effects like anxiety, panic, dysphoria, paranoia, fear, confusion, agitation, and challenging experiences or "bad trips" (Baumeister, Tojo, and Tracy 2015; Hirschfeld et al 2021) Naturalistic use, without proper screening or support, is more likely to lead to adverse psychological outcomes (Carbonaro et al., 2016; Scala et al., 2024).
● Physiological: Physical side effects may include nausea, headaches, dizziness, increased heart rate and blood pressure, sweating, tremors, and dilated pupils (Baumeister, Tojo, and Tracy 2015)
Long-Term Adverse Effects
● Hallucinogen Persisting Perception Disorder (HPPD): HPPD is characterized by recurring perceptual disturbances like visual distortions, flashbacks, and altered sensory perceptions (Holze et al 2022)
○ HPPD may be triggered by frequent, high-dose, or long-term use, but can occur after a single experience (Hirschfeld et al 2021)
○ HPPD is thought to be less common in controlled settings, and no contemporary clinical trials have reported HPPD developing in participants (Lacroix et al. 2024).
○ Younger individuals may be at higher risk for persistent perceptual symptoms (Lacroix et al. 2024).
○ Individuals with a history of substance misuse are more likely to be diagnosed with Hallucinogen Persisting Perception Disorder (HPPD) (Martinotti et al 2018)
○ In one study of psychedelic users who experienced negative effects, 25% reported HPPD symptoms in a questionnaire and 40% in interviews (Bremler et al 2023) However, only a small minority experience clinically significant distress or impairment from these symptoms(Bremler et al. 2023).
○ While prevalence estimates for HPPD vary, one source indicates rates ranging from 1 in 4 to 1 in 20, and from 15 to 77% of psychedelic users(Ortiz Bernal et al 2022) However, these rates may be inflated due to methodological concerns (Ortiz Bernal et al. 2022)
○ Reactivation of psychedelic effects was reported by about one-third (33%) of veterans surveyed, and may be more common with the concurrent use of multiple psychedelics or with their use in uncontrolled environments (Davis et al , n d )
● Prolonged psychotic reactions: Although rare, prolonged psychotic reactions can occur after psychedelic use (Baumeister, Tojo, and Tracy 2015; Barnett and Greer 2021; Sabé et al 2024), especially in individuals predisposed to psychosis Reactions can last for days, weeks, or longer(Breeksema et al. 2022). Although rare, psychotic reactions can occur with any psychedelic (Ramaekers, Reckweg, and Mason 2025b). Individuals with a personal or family history of psychosis are at greater risk for long-lasting psychotic reactions (White et al. 2024; Barber and Dike 2023; 2023; Henningfield et al. 2023). Some individuals who experience psychotic reactions after taking a classic psychedelic are suspected to have a pre-existing vulnerability(Johnson et al 2019)
● Worsening of pre-existing mental health conditions: Existing mental health conditions, especially personality disorders, may be exacerbated by psychedelic use (Bremler et al 2023; Marrocu et al , n d ) 31% of those with pre-existing personality disorders reported negative responses to psychedelics, a four-fold increased risk (Marrocu et al , n d )
● Negative psychological effects: Negative psychological effects such as anxiety, depression, paranoia, and emotional instability can persist after a challenging psychedelic experience (Bremler et al 2023; Evans et al 2023; O Robinson et al 2024). Anxiety is the most prevalent symptom reported in individuals who have had negative experiences after psychedelic use, reported by 81-93% of individuals in a study focused on negative experiences (Bremler et al 2023) In a study of naturalistic psychedelic use, close to 10% of users who had challenging experiences reported negative psychological symptoms lasting over 12 months (Orłowski et al 2022)
● Functional impairment: Epidemiological research suggests that approximately 9-13% of non-clinical trial psychedelic users have experienced negative outcomes that included functional impairment in the days or weeks after dosing (Palitsky et al , n d ; O Robinson
et al 2024) Some individuals require medical, psychiatric or psychological assistance (Palitsky et al., n.d.).
● Persisting adverse reactions: A survey of Norwegian psychedelic users found that 23% reported persisting adverse reactions lasting longer than a day, with a fifth of those reporting difficulties lasting longer than a year (Robinson et al 2024).
● Negative emotional states: While negative emotional states during the psychedelic experience may be therapeutic, one study suggests that an experience of dread during the psychedelic experience negatively predicts treatment outcomes (Forstmann and Sagioglou 2021).
● Suicidal ideation: There is a concern for increased risk of suicide after psychedelic experiences (Kruger et al 2024; Hinkle et al 2024) However, this is not typically seen in controlled settings and may be due to other underlying issues(Johnson et al 2019; Rosenblat et al 2023)
● Physical harm: A small percentage of individuals (approximately 4.67%) report that their behavior during their most recent psychedelic experience put themselves at risk of physical harm (Kruger et al 2024)
● Problematic relationships with psychedelics: Nearly one-quarter of veterans who had used psychedelics reported cravings to use (26%) and attempts to reduce their use (25%) (Davis et al , n d ) 20% of veteran respondents in one survey reported physical dependence and 16% reported psychological dependence (Davis et al., n.d.).
Prevalence Data
Emergency Room Visits: In 2020, 1% of people who consumed LSD, 1% who consumed MDMA, 0 6% who consumed ketamine, and 0 6% who consumed psilocybin sought emergency medical care. These figures, though relatively low, are concerning given the rising rates of psychedelic use. These visits are primarily due to psychological issues such as distress, panic, or an inability to control the altered state, rather than toxicity or overdose (Canady 2023).
2. Substance Risk Profiles
Risks related to ingesting substances are frequently dependent upon the amount of the substance consumed. Before diving into the risks of each specific substance, it’s important to define the terms “macrodosing,” “microdosing,” and “mididosing,” as they will appear regularly in this literature review
Macrodosing involves taking a high dose of a psychedelic substance to induce a full psychedelic experience, characterized by significant changes in perception, thought, and sense of self (Nichols, 2016). This often results in ego dissolution, where individuals feel a loss of personal identity and may experience mystical or spiritual insights (Nour et al., 2016; Griffiths et al , 2008) Macrodosing is common in therapeutic settings, where it is combined with
psychotherapy to treat conditions like depression and PTSD, and in ceremonial contexts, often guided by shamans or facilitators (Reiff et al., 2020). Recreational use also occurs, though it carries the risk of overwhelming experiences such as anxiety or paranoia The frequency of macrodosing varies, with some using it regularly for personal growth or healing, and others more occasionally for specific purposes. It’s important to approach macrodosing with caution, as high doses can lead to intense and unpredictable experiences, necessitating a safe environment and, in some cases, professional support (Carbonaro et al., 2016)
Microdosing refers to the practice of consuming very low, sub-hallucinogenic doses of a psychedelic substance. The goal of microdosing is to enhance cognitive function, improve mental health, or promote personal development without triggering a full psychedelic experience (Baxter et al , 2024; Anderson et al , 2019; Polito & Liknaitzky, 2022) Microdosing regimens vary, but a popular schedule involves one dosing day followed by two days without dosing (Fadiman, 2011) While microdosing has gained interest, current research is limited, and further investigation is needed to determine whether the reported benefits are due to a placebo effect or a genuine pharmacological impact. Many microdosing studies rely on convenience samples, which may not be representative of the broader population, particularly underreporting those who discontinued microdosing due to negative or negligible effects (Bornemann, 2020) Additionally, the absence of a clear definition of what constitutes a "microdose" complicates comparisons across studies, making it difficult to standardize doses (Syed et al , n d )
Psilocybin
Overview
Definition and Description
Psilocybin is a naturally occurring psychoactive compound found in over 200 species of mushrooms, most commonly within the Psilocybe genus (Guzmán, 2005; 2019) For centuries, these mushrooms have been used in various cultures for religious and divinatory purposes (Spiers et al , 2024; Winkelman, 2019; Guzmán, 2019) It is classified as a classical serotonergic psychedelic, meaning it primarily exerts its effects through the activation of serotonin receptors in the brain, leading to alterations in perception, cognition, emotion, and self-awareness (Vollenweider & Smallridge, 2022; Studerus et al , 2011; Griffiths et al , 2006)
Psilocybin use is widespread in North America and Europe. 8.7% of the US population aged 12 and older (22.9 million people) reporting use at some point in their lifetimes, and 11.7% of Canadians reporting having used it at least once (Carbonaro et al , 2016; Lake & Lucas, 2023) Among those who began using hallucinogens between 2004 and 2005, over half of them (52%) began with psilocybin (Carbonaro et al , 2016) Surveys conducted across 12 European Union countries reveal that the prevalence of magic mushroom use among individuals aged 15-24 ranges from 1% to 8% (EMCDDA, 2006). In 2004, approximately 340,000 people aged 16 to 59 in the United Kingdom reported using magic mushrooms (Roe, 2005) Whereas, the prevalence of magic mushroom use in the Netherlands dropped from 6 3% in 2000 to 2 9% in 2005 (van Amsterdam et al., 2011). Following the prohibition of magic mushrooms at the end of 2008, the
use significantly declined, with the last recorded prevalence in 2009 being just 0 1% (Trimbos, 2010).
Most psilocybin use is recreational Many individuals report just a few occasions of use over the course of their lifetimes (M. W. Johnson et al., 2018). Additionally, microdosing has gained popularity, with 55% of participants in a recent study reporting using psilocybin this way (Lea et al , 2020)
Primary Classification
Upon ingestion, psilocybin is rapidly metabolized into psilocin, the active compound responsible for its psychoactive effects. This conversion occurs predominantly in the stomach, suggesting that fasting prior to consumption may enhance the therapeutic experience (Dodd et al , 2022; Ling et al., 2022). Psilocin interacts mainly with the 5-HT1A, 5-HT2A, and 5-HT2C receptors, showing a particularly strong affinity for the 5-HT2A receptor (Grob et al , 2022; Hasler et al , 2004) This interaction with the serotonergic system is believed to be the primary mechanism through which psilocybin induces altered states of consciousness (Grob et al., 2022; Bender & Hellerstein, 2022; Hasler et al , 2004)
Subjective Effects
Psilocybin’s subjective effects vary depending on the dose and individual response to its active compound These effects typically begin within 20-40 minutes of consumption, peak within 60-90 minutes, and gradually subside over the course of 3-6 hours (Bender & Hellerstein, 2022; Daniel & Haberman, 2017) Psilocybin’s impact on mood, perception, cognition, and self-awareness can be categorized into acute, subacute, and long-term effects (Studerus et al., 2016), detailed below.
Acute Effects: Psilocybin induces profound alterations in mood, perception, and thought in a dose-dependent manner. Most users report positive and enriching experiences characterized by depersonalization, derealization, and altered time perception However, a small proportion of users experience adverse reactions, such as anxiety, panic, and dysphoria, especially at higher doses (Studerus et al., 2016). Participants reported disturbances to cognitive functions and somatesthesia (bodily perception) which was considered unpleasant Most people were still able to distinguish between their altered experiences and reality. They were able to maintain a sense of distance, often thinking, "It’s as if " they were experiencing something unusual, rather than fully losing touch with reality (Studerus et al , 2016) Auditory distortions are typically mild, with true auditory hallucinations being rare. Psilocybin also reduces vigilance, an effect not typically associated with other hallucinogens (Studerus et al , 2016)
Subacute Effects: Emotional excitement, heightened mood, and increased concentration peak within the first 60-180 minutes after ingestion, while sensations of dreaminess, inactivation, and introversion become more pronounced after 260-400 minutes During this later phase, derealization and depersonalization may intensify, and subjects often exhibit more inward-focused experiences (Studerus et al , 2016)
Long-term Effects: Long-term follow-up studies (8-16 months post-session) reveal that the majority of subjects maintain a positive view of their psilocybin experience, with over 60% rating it as “highly enriching” and more than 90% as at least “moderately enriching ” This positive retrospective evaluation is consistent even among those who experienced distress during the acute phase (Studerus et al., 2016).
Evidence for Therapeutic Use in the Mental Health Setting
Recently, psilocybin has garnered significant interest because of its potential for treating various mental health disorders particularly those resistant to conventional therapies Multiple clinical trials and studies have explored its effectiveness in managing conditions like major depressive disorder (MDD), anxiety, substance use disorders, and psychological distress associated with terminal illness (Lowe et al , 2021)
● In depression treatment, psilocybin, especially when combined with psychotherapy, has shown promising results Several randomized controlled trials (RCTs) have highlighted its antidepressant potential, particularly in treatment-resistant depression (TRD; Borissova & Rucker, 2023) For instance, the recent study by Goodwin et al , (2023) investigating a synthetic psilocybin formulation, COMP360, reported improvements in subjects’ depressive symptoms that were comparable to those associated with conventional antidepressants such as SSRIs
Psilocybin-assisted psychotherapy (PAP) has also shown promise in reducing depression and anxiety in individuals with terminal illnesses, such as cancer, further demonstrating its potential for treating difficult-to-manage mood disorders (Ross et al , 2016; Grob et al , 2011; Griffiths et al., 2016; Bader et al., 2024) . A single dose of psilocybin has been shown to lead to significant reductions in both anxiety and depression, with these benefits often lasting several months (Griffiths et al , 2016)
Psilocybin has shown potential in treating substance use disorders Clinical studies suggest that it can help reduce alcohol consumption and assist in quitting smoking when used alongside therapy (Johnson et al. 2014; 2016; Garcia-Romeu, 2019; Bogenschutz et al., 2019). These results indicate that psilocybin may play a role in promoting long-term behavioral changes in addiction recoveryAdditionally, research indicates that the positive effects of psilocybin on emotional well-being may persist beyond the immediate treatment period, suggesting possible long-term benefits (Nayak et al , 2023)
However, despite the encouraging evidence, factors such as small sample sizes, inconsistencies in dosing, and methodological limitations in some studies have raised concerns about this research Further studies are needed to establish psilocybin's long-term safety and efficacy, particularly in diverse patient populations. Recent developments, such as the FDA-granting breakthrough therapy designation to psilocybin for treatment-resistant depression, underscore the growing recognition of its therapeutic potential.
Dosing
Psilocybin dosages vary based on desired outcomes, chosen forms of ingestion and other individual factors. For dried mushrooms, typical microdoses range from 0.1 to 0.5 grams (Cavanna et al , 2022), while recreational doses generally fall between 1 and 5 grams (Lea et al., 2020). In therapeutic trials using pure psilocybin, doses typically range from 1.75 to 30 mg, with a median dose of 21 mg for a 70 kg participant (Engel et al., 2024). Psilocybin doses are also categorized into five groups according to their subjective effects: Threshold (2 mg), Light (3-6 mg), Common (6-15 mg), Strong (15-30 mg), and Heavy (30 mg+) (Engel et al., 2024). These categories are estimates and can vary depending on individual factors
Microdoses are considered to be those that fall between 1/10th and 1/20th of a recreational dose. Microdosing results in effects that do not induce visual or perceptual changes. For dried mushrooms, microdoses are usually around 0 1 to 0 4 grams (Fadiman & Korb, 2019; Polito & Liknaitzky, 2022). For synthetic psilocybin, they are about 0.8 to 5 mg. Some studies have used slightly higher ranges, such as 0 1 to 1g of dried mushrooms (Savides & Outhoff, 2024)
Macrodosing, which leads to full psychedelic experiences, generally involves doses ranging from 1 to 5 grams of dried mushrooms (Polito & Liknaitzky, 2022), though some users take up to 15 grams Synthetic psilocybin doses for macrodosing typically range from 17 to 30 mg (Polito & Liknaitzky, 2022). A moderate to high dose is considered to be around 4 grams of dried mushrooms (Carbonaro et al , 2016) It's important to note that 10 mg of psilocybin is considered an active oral dose, with stronger effects occurring at higher doses (Grob, Bossis, & Griffiths, 2022).
Interestingly, body weight does not significantly influence the effects of psilocybin, making weight-adjusted dosing unnecessary (Holze et al., 2023; Syed et al., n.d.).
Frequency
Microdosing: Microdosing regimens are not standardized, but a common practice is to take a microdose every third day (one day on, two days off) Some individuals report microdosing for periods of up to six months (Lea et al , 2020)
Macrodosing: The frequency of macrodosing varies widely, depending on personal preferences and goals Some individuals may use psilocybin infrequently for recreational purposes, while others may incorporate it more regularly in therapeutic settings. In clinical and therapeutic contexts, psilocybin is often administered in one or a few sessions that are followed by integration therapy directed at helping individuals process their experiences (Aday et al , 2020) Optimal dosing intervals are still being investigated. While in clinical studies, single-dose protocols are common, In more naturalistic settings, some individuals report taking more than one dose in a session
Psilocybin is generally regarded as physiologically safe, with a low potential for addiction (Hasler et al , 2004; Martins et al , 2023) However, potential risk factors, contraindications, relative contraindications, and both acute and long-term adverse effects of its use exist. These will be discussed in the following sections
Psilocybin-Specific Risk Factors
Please refer to the “Risk Factors of All Psychedelic Substances” section above for an exhaustive discussion of general psychedelic risk factors, all of which apply to the use of psilocybin. Psilocybin-specific risk factors are listed below.
Dosage and Potency
Higher doses of psilocybin are associated with an increased likelihood of adverse effects, including physical harm, anxiety, and physiological discomfort For example, in a study by Carbonaro et al. (2016), 11% of participants reported putting themselves or others at risk under the influence of higher doses Similarly, higher doses were found to correlate with more challenging experiences, such as Dread of Ego Dissolution (DED), a measure of unpleasant psychedelic states (Studerus et al., 2012). Griffiths et al. (2016) also observed that a high dose of psilocybin (22 mg/70 kg) resulted in 32% of participants experiencing discomfort and 26% reporting anxiety High doses can also cause delayed-onset headaches (Griffiths et al , 2016) Additionally, Dahmane et al. (2021) found that a 25 mg dose of psilocybin caused a slight effect on QTc prolongation, but this was deemed to pose a low risk according to the FDA's guidelines for non-cardiac medications
The psilocybin content in mushrooms can vary significantly, making precise dosing difficult and therefore increasing the risk of unexpectedly strong effects (Johnson et al , 2018; Polito & Liknaitzky, 2022). The use of unregulated, illicit psilocybin mushrooms outside of controlled settings compounds this risk due to potential adulteration and the unknown quality of the substance (Bender & Hellerstein, 2022; Barber & Dike, 2023)
Psychological and Individual Factors
As is the case with all psychedelic substances, psilocybin’s effects can be influenced not only by dosage but also by psychological and individual factors (Scala et al., 2024). See “Risk Factors Associated with All Psychedelic Substances” above
Individuals with a history of mental health conditions such as psychosis, mania, hypomania, or violence are at a heightened risk for adverse psychological effects from psilocybin, including the exacerbation of pre-existing conditions like psychosis or bipolar disorder (Rosenblat et al , 2023; Amsterdam et al.,2011). Psilocybin may induce a psychotic state that mimics aspects of schizophrenia, which is especially concerning for those with a family history of the condition (Amsterdam et al., 2011).
While psilocybin is not generally associated with increased suicidality on a population level, there have been instances of suicidal behavior following its use, particularly in those with prior suicidal thoughts or attempts (Freitas et al., 2024). In one clinical trial for treatment resistant depression, participants exhibited symptoms of suicidal ideation and non-suicidal self-injurious behaviour in the active treatment groups (Goodwin et al., 2022). A case report of a 60-year-old
man with recurring depression and a history of delusions passed away following psilocybin-assisted therapy (Müller et al., 2024). The therapy may have triggered delusions and emotional instability, potentially contributing to his death This case highlights that delusional symptoms may be a contraindication for psychedelic treatments and stresses the importance of careful evaluation and close monitoring in complex cases.(Müller et al., 2024)
Younger individuals are more likely to experience challenging psilocybin effects and require emergency medical treatment, potentially due to lower risk aversion, higher impulsivity, and difficulties in emotional regulation (Kopra et al , 2022)
One of the key risks associated with psilocybin use is the potential for a "bad trip" or challenging experience These episodes can involve intense emotions such as fear, paranoia, disorientation, and a sense of losing control “Bad trips” are common and can include experiences of intense anxiety, fear, paranoia, panic, or a sense of losing touch with reality (Evans et al., 2023). Studies suggest that between 35 and 39% of users in one survey rated their worst experience with psilocybin as one of the top five most challenging experiences of their lives (Smith and Sisti 2021; Anderson et al. 2019; Carbonaro et al., 2016). While these experiences are often distressing, many individuals report that they ultimately lead to personal growth and learning, even when the trip was difficult (Straumann et al., 2024). A history of negative psychedelic experiences, or "bad trips," increases the likelihood of similar experiences in the future Individuals who have previously encountered distressing trips are more likely to face similar challenges, particularly if they have unresolved psychological distress from those past experiences (Bremler et al , 2023; Strassman 1984)
Physical Health Conditions
Individuals with significant underlying cardiovascular, neurological, hepatic, or renal conditions may be at an increased risk for medical complications when using psilocybin, though because most studies have excluded these populations from participation, it is difficult to state this conclusively (Bender & Hellerstein, 2022) There is also concern regarding valvular heart disease (VHD) with regular or excessive use of psilocybin, although as of yet, no cases have been reported with typical psilocybin use (Fonzo et al 2025) Additionally, individuals with conditions such as spinal cord injuries may be at a higher risk of experiencing adverse effects, including autonomic and neuromuscular hyperactivity, which could be exacerbated by the physiological changes induced by psilocybin (Abrams et al , 2023)
Polysubstance Use and Drug Interactions
Individuals with a history of substance use disorders or polydrug use may be at an increased risk for adverse reactions when using psilocybin (Roberts et al , 2020) Combining psilocybin with other substances, such as alcohol or cannabis, can further heighten the risk of negative outcomes (Bennett et al , 2023; Griffiths et al , 2006) While some users have reported that cannabis can help reduce the difficulty of a challenging experience, others have found that it significantly exacerbates the trip (Carbonaro et al , 2016; Scala et al , 2024) The use of cannabis, particularly before or during psilocybin use, can increase the intensity of the
experience and contribute to more negative effects, further highlighting the unpredictable nature of combining substances (Carbonaro et al., 2016).
Combining psilocybin with Selective Serotonin Reuptake Inhibitors (SSRIs) or other serotonergic medications may increase the risk of serotonin syndrome, characterized by symptoms like hypertension and tachycardia, and in rare instances, more severe symptoms such as cardiac events, seizures, and even fatalities (Bender and Hellerstein 2022; Sakai et al 2024). While clinical trials typically prohibit concomitant SSRI use, recent studies suggest that the overall risk is not elevated, although severe blood pressure increases may occur (Sakai et al. 2024).
Risk Factors Related to Routes of Administration
The method of administering psilocybin plays a crucial role in determining the onset, intensity, and duration of its effects Different routes of administration carry unique risk profiles that should be considered in both clinical or recreational settings.
Oral
Administration
Oral ingestion of psilocybin-containing mushrooms or other psilocybin formulations is the most common method of administration After ingestion, psilocybin is metabolized into psilocin, the active compound responsible for its psychoactive effects (Carbonaro et al , 2018)
Risks:
● Variable onset and intensity: Oral administration typically leads to a slower onset of effects, which can create uncertainty and cause some users to consume additional doses before the effects fully manifest, increasing the risk of overdose (Dourron et al , 2023).
● Gastrointestinal discomfort: Nausea and vomiting are common with oral ingestion, particularly due to the difficulty of digesting the mushroom material itself A meta-analysis revealed that psilocybin has a significantly higher likelihood of causing nausea when compared to a placebo (M W Johnson et al , 2019)
● Dosing inaccuracy: The psilocybin content in mushrooms varies significantly, so oral ingestion of mushroom bodies can lead to unpredictable effects and an increased risk of negative experiences (M W Johnson et al , 2018)
● Psychological distress: While less frequent than with other forms of administration, oral ingestion can still result in anxiety, fear, or panic, especially in individuals who are unprepared or lack sufficient support during their experience
Risk Factors Related to Quality, Sourcing, and Potential Contamination
Psilocybin quality, sourcing, and potential contamination are significant factors influencing both the safety and efficacy of the substance. These factors primarily concern the sourcing of psilocybin, potential adulteration, variability in potency, and improper storage, all of which can increase the risk of adverse experiences.
Variability in Potency and Dosing Inaccuracy
One of the primary risks of psilocybin consumption is the variability in potency, which can result from differences in mushroom species, growing conditions, and preservation methods (Kopra et al , 2022) Even within the same species, the psilocybin content of mushrooms can fluctuate significantly, making it difficult for users to achieve consistent and predictable dosing. This variability increases the risk of unintended overdoses or challenging psychological experiences (Cavanna et al , 2022; M W Johnson et al , 2018) Inaccurate dosing is particularly problematic in microdosing, where small variations can lead to overwhelming effects (M. W. Johnson et al., 2018)
Sourcing from Unregulated Markets
Without regulatory oversight, users cannot verify the purity, potency, or composition of the psilocybin they purchase. This creates significant risks related to the unknown quality and potential contaminants, especially in the illicit market (Petranker et al , 2022; Bienemann et al , 2020) The lack of safety guarantees increases the likelihood of consuming adulterated substances that may cause unexpected or dangerous reactions.
Adulteration and Contaminants
Psilocybin products can be adulterated with cheaper, potentially harmful substances. Some psilocybin products, such as powdered mushrooms, can be contaminated with other psychedelics like substituted dimethoxyamphetamines (e g , DOx family) or N-benzyl-phenethylamines (e.g., 25x-NBOMe family), which may cause severe side effects, including hospitalizations and overdose (Petranker et al , 2022) Furthermore, there is the risk of consuming misidentified mushrooms that could be toxic, leading to poisoning or severe health issues (Kopra et al , 2022)
Storage and Degradation
The potency of psilocybin decreases over time, especially when stored improperly Psilocybin can lose up to 50% of its potency within months of storage, which makes it difficult to accurately assess the dosage and may lead to weaker effects than expected (Cavanna et al., 2022). This degradation is particularly pronounced in fresh mushrooms compared to dried ones, further complicating the consistency of dosage over time (Gotvaldová et al , 2020)
Lack of Testing and Quality Control
Due to the illicit nature of psilocybin, users often lack access to drug-testing services or kits, which could help identify potential contaminants or determine the actual composition of the substance Drug testing services that are available may not always detect novel psychoactive substances or adulterants (Petranker et al., 2022).
Contraindications
Psilocybin has a generally favorable safety profile; however, there are certain conditions under which psilocybin use is either absolutely contraindicated or should be approached with caution These are described below
Absolute Contraindications
These are conditions where psilocybin use is completely inadvisable due to the high risk of significant harm:
1 Active psychosis or a history of psychosis: Individuals currently experiencing psychosis or those with a history of psychotic episodes (including schizophrenia) should not use psilocybin, as it can induce a psychotic state and/or exacerbate these conditions (Rosenblat et al , 2023; Amsterdam, Opperhuizen, & Brink, 2011)
2. Active mania or hypomania: Psilocybin is contraindicated in individuals currently experiencing manic or hypomanic episodes, as it may worsen these states and/or trigger more severe manic episodes (Rosenblat et al , 2023)
3. Severe unstable cardiovascular conditions: Psilocybin should not be used in individuals with severe unstable cardiovascular diseases, including uncontrolled hypertension and arrhythmias, due to the potential for increased heart rate and blood pressure (Fonzo et al , 2025; Bender & Hellerstein, 2022) associated with psilocybin use
4 Known allergy or hypersensitivity to psilocybin or mushrooms: Though rare, those with an allergy or hypersensitivity to psilocybin or psilocybin-containing mushrooms should avoid its use
5 Pregnancy: Psilocybin is contraindicated for pregnant individuals as its effects on pregnancy and fetal development are not well-understood (Bennett et al., 2023).
Relative Contraindications
These are conditions where psilocybin use may still be possible but requires careful evaluation, monitoring, and risk-benefit assessment:
1 The use of certain medications: Concurrent use of serotonergic medications (such as SSRIs, MAOIs, or lithium) and psilocybin is a relative contraindication due to the increased risk of serotonin syndrome, which can be fatal (Kopra et al , 2022; Malcolm & Thomas, 2022).
2
Family history of psychosis or bipolar disorder: Individuals with a family history of psychosis or bipolar disorder may be at higher risk for adverse reactions and should be closely monitored (Rosenblat et al , 2023)
3. Significant unstable mental health disorders: Individuals with unstable mental health conditions, such as severe depression with active suicidal ideation, require careful consideration as well as close monitoring and support (Freitas et al , 2024; Kruger et al , 2024).
4 Known QTc concerns or medications affecting QTc: Individuals with a known history of QTc prolongation or those taking medications that affect QTc interval should be evaluated carefully. An ECG and electrolyte panel are recommended before administering psilocybin (Bennett et al , 2023; Ghaznavi et al , 2025)
5 History of substance use disorders: Individuals with a history of substance use disorders may be more vulnerable to adverse reactions. Their cases should be carefully considered, and proper support should be in place (Studerus et al , 2011)
6. Dementia or delirium: Psilocybin use in individuals with dementia or delirium could exacerbate cognitive impairments, and its effects may be difficult to manage in these populations (Bennett et al , 2023)
7. Malnourishment or electrolyte imbalances: Individuals who are malnourished or have electrolyte imbalances should undergo proper evaluation before using psilocybin Bloodwork should be conducted to assess electrolytes and overall health (Bennett et al , 2023).
8 Age: While psilocybin has primarily been studied in individuals between18 and 65 years of age, effects in younger and older populations are less understood. Caution should be exercised when considering psilocybin use in individuals outside this age range (Bennett et al , 2023)
9. History of trauma: Psilocybin may trigger the re-experiencing of traumatic events in individuals with a history of significant trauma While psilocybin has therapeutic potential for some of these individuals, additional psychological support is recommended (Smith & Sisti, 2021; Fonzo et al., 2025).
Adverse Events
Psilocybin is generally regarded as safe, especially when used in controlled settings. However, like many psychoactive substances, it can lead to both acute and long-term adverse effects. The intensity and nature of these effects are influenced by factors such as dosage, individual sensitivity, pre-existing conditions, and the environment in which the substance is consumed
Acute adverse effects are those that occur during or shortly after psilocybin administration, typically within hours, while long-term effects may persist for weeks, months, or longer
Acute Adverse Effects of Macrodosing
Psychological Effects
1 Challenging Experiences ("Bad Trips"): See “Risk Factors Associated with All Psychedelic Substances: above.
2. Anxiety and paranoia: Anxiety is a commonly reported acute effect of psilocybin, with rates of occurrence ranging from 2% to 100% of users (Freitas et al , 2024) In one study, 31% of participants reported acute anxiety during the session, although it did not persist beyond the treatment (Forstmann & Sagioglou, 2021). 15.6% of participants in a combined analysis of studies reported anxiety on the day of the psilocybin session (Freitas et al., 2024). In many cases, anxiety is mild to moderate and can be managed with reassurance, particularly in controlled settings (Freitas et al , 2024; Scala et al , 2024) However, it can sometimes escalate into panic attacks, especially in individuals with pre-existing mental health conditions, such as schizophrenia or bipolar disorder.
3 Psychotic Symptoms: Psilocybin can induce transient psychotic-like symptoms, including paranoia, hallucinations, and derealization (Scala et al , 2024; Carhart-Harris & Nutt, 2010). These symptoms are both rare and generally temporary, but they can be prolonged in a small percentage of users, with some experiencing persistent psychotic episodes (Carhart-Harris & Nutt, 2010; Bouso et al., 2022). In uncontrolled environments, the likelihood of prolonged psychosis is higher (Carhart-Harris & Nutt, 2010)
4. Cognitive and Perceptual Changes: Psilocybin produces an altered state of consciousness, resulting in changes to perception, cognition, and sense of self This includes distortions in time, space, colors, and sounds (Bender & Hellerstein, 2022) These perceptual changes are typically a key part of the psychedelic experience but can contribute to confusion and disorientation (Scala et al , 2024)
5 Mood Changes: Emotional lability a rapid shift in emotional states is another psychological effect that can occur during a psilocybin experience. These shifts can involve intense positive or negative emotions, including tearfulness and sadness (Rosenblat et al., 2023). Such emotional fluctuations may be unsettling for some individuals, particularly those with a history of mental health issues
6 Re-experiencing of Past Trauma: Psilocybin can trigger the re-experiencing of past traumatic events, which may be difficult to process for individuals with a history of trauma (Fonzo et al , 2025)
7 Impaired Decision-Making: Psilocybin use can impair decision-making, leading to risky behaviors. One study found that 10.7% of users reported putting themselves or others at risk of physical harm, and 2 6% exhibited violent or aggressive behavior (Bienemann et al , 2020) This is particularly concerning in uncontrolled environments without a trusted guide.
Physiological Effects
1. Cardiovascular changes: Psilocybin can cause mild cardiovascular stimulation, including increases in heart rate and blood pressure Tachycardia (heart rate >100 bpm) has been observed in 7% of psilocybin administrations (Straumann et al., 2024), and systolic blood pressure over 160 mmHg and diastolic pressures over 100 mmHg have
been noted, particularly in older patients with underlying medical conditions (Bender & Hellerstein, 2022).
2 Gastrointestinal effects: Nausea is one of the most commonly reported side effects of psilocybin, with up to 39% of participants experiencing it within 12 hours of ingestion (Straumann et al., 2024). Vomiting, while less common, has also been reported (Bender & Hellerstein, 2022) These gastrointestinal symptoms are usually temporary and subside within a few hours of ingestion.
3 Headache: Headache is another common acute side effect of psilocybin, with 55% of participants reporting it within 12 hours of ingestion and 42% experiencing it up to 24 hours afterward (Straumann et al., 2024). The intensity of headaches is more pronounced with higher doses (Bender & Hellerstein, 2022)
4 Other Physical Discomforts: Additional physical effects associated with psilocybin include pupillary dilation, tremors, hyperreflexia (exaggerated reflexes), dizziness, ataxia (loss of coordination), chills, motor agitation, excessive sweating (hyperhidrosis), diarrhea, and urinary incontinence (Bender & Hellerstein, 2022). Fatigue, lack of concentration, lethargy, vertigo, and decreased appetite are also frequently reported (Straumann et al , 2024)
Long-Term Adverse Effects of Macrodosing
Psychological Effects
1. Enduring psychological symptoms: A subset of individuals may experience persistent negative psychological effects following psilocybin use, particularly after challenging experiences In a survey, 24% of participants reported experiencing symptoms like anxiety, paranoia, depression, or fear that lasted for a week or more, with 10% experiencing symptoms lasting up to 12 months Some individuals (7 6%) sought professional treatment for these symptoms (Bender & Hellerstein, 2022; Carbonaro et al., 2016; Evans et al., 2023).
2 Hallucinogen persisting perception disorder (HPPD): HPPD is characterized by persistent visual disturbances, such as visual snow, halos, or intensified colors, long after the drug has worn off. While this condition is primarily associated with LSD, there have been reports of HPPD following recreational psilocybin use, particularly in combination with alcohol or cannabis. HPPD is considered rare in clinical settings where psilocybin is used therapeutically, but further research is needed to better understand its long-term impact in this context (Scala et al , 2024; Rosenblat et al , 2023)
3. Flashbacks: 6% of healthy participants in a controlled study reported flashbacks after psilocybin use (Straumann et al 2024; 2024)
4 Prolonged psychosis: Though rare, there is a risk of prolonged psychotic symptoms, such as paranoia or hallucinations, following psilocybin use (Johnson & Griffiths, 2008; Barber et al , 2022) These symptoms are more likely to occur in individuals with pre-existing risk factors, such as a family history of psychosis (Simonsson et al , 2023) One study found that 2.5% of participants experienced prolonged psychosis following psilocybin use (Carhart-Harris & Nutt, 2010)
5
Suicidal ideation: Suicidal ideation, while uncommon, has been reported in some trials (Palitsky, Canby, et al., n.d.; Freitas et al. 2024), particularly among individuals with a history of suicidal thoughts In one study, 6% of participants experienced suicidal ideation, and some reported worsened thoughts following psilocybin use (Freitas et al., 2024).
6 Mania and mood changes: In rare cases, psilocybin use has been linked to the onset of mania, especially in individuals with pre-existing conditions like bipolar disorder. Some individuals also experience prolonged mood shifts, both positive and negative, after its use (Palitsky, Kaplan, et al , n d ; Forstmann & Sagioglou, 2021)
7. Reactivation of trauma: Individuals with a history of trauma may experience the reactivation of traumatic memories and emotions when taking psilocybin This can lead to increased anxiety, shame, or emotional distress (Mehtani et al. 2024) One case study described a patient who experienced a PTSD flashback of sexual assault two days after psilocybin-assisted therapy (Scala et al., 2024).
Physiological Effects
1. Addiction/psychological dependence: While physical dependence is not a concern with psilocybin, there are some concerns about the potential for psychological dependence, especially in individuals who use psilocybin frequently or in unregulated settings. However, these concerns are largely theoretical (Rosenblat et al., 2023).
2 Cardiovascular effects: The long-term cardiovascular effects of psilocybin are not well documented However, there is concern over the potential long-term effects of 5-HT2B receptor agonism and its possible association with cardiac fibrosis (Savides & Outhoff, 2024) These effects are still under investigation
3. Other physical symptoms: Though not common, some case reports mention other physical problems following psilocybin use, including dizziness and general discomfort (Carbonaro et al , 2016)
Cognitive and Functional Effects
1 Cognitive Impairment: Although rare, some users report mild-to-severe sustained cognitive impairment after using psilocybin. The prevalence and long-term impact of this effect are not well-established, and further studies are required (Bender & Hellerstein, 2022)
2. Impaired Functioning: Some individuals may experience long-lasting adverse effects that affect their daily functioning, such as reduced work productivity or difficulties in social relationships. This can persist for weeks or months after the experience (Palitsky, Canby, et al , n d )
Other Considerations
1 Lack of longitudinal data: The long-term effects of psilocybin are still not fully understood due to the limited availability of extensive longitudinal data Most current studies have follow-up periods of less than 12 months, with a few secondary analyses
extending up to 4 5 years (Forstmann & Sagioglou, 2021; Scala et al , 2024) More comprehensive research is needed to understand the full scope of psilocybin's long-term impact
2. Emergency room visits: In 2011, there were 83 emergency room references to problems with psilocybin alone compared to 10,309 references to heroin alone (Carbonaro et al 2016; 2016; 2016; 2016)
3. Adverse events in naturalistic use: In a survey of 1,993 individuals who used psilocybin mushrooms in a non-clinical setting and had a challenging experience, 8% reported that their most challenging experience led to a decrease in their sense of well-being or life satisfaction, 11% reported putting themselves or others at risk of physical harm, 3% reported being physically aggressive or violent toward themselves or others, and 3% reported receiving help at a hospital or emergency department (8) Moreover, 10% indicated that they experienced negative symptoms, such as fear, anxiety, depression, or paranoia, that persisted more than 12 months after using the psilocybin mushrooms, and 8% sought treatment for their symptoms. Those who had been treated for psychological symptoms prior to the bad trip were more than twice as likely to pursue treatment for their symptoms as were those with no history of treatment (Palitsky et al., n.d.).
Adverse Events of Microdosing
Psilocybin microdosing has gained popularity as a way to experience the potential benefits of the substance while minimizing its risks It is commonly used to achieve subtle positive psychological effects, such as enhanced mood and cognitive function While research into its adverse effects is still developing (Bornemann, 2020; M. W. Johnson et al., 2018; Savides & Outhoff, 2024), microdosing is intended to provide benefits such as improved mood and cognition without causing the significant cognitive or perceptual distortions typically associated with higher doses (Savides & Outhoff, 2024).
Although microdosing generally carries a lower risk profile than full doses, it can still lead to psychological and physiological side effects that are often less intense but still important to consider For example, 20 2% of microdosers reported experiencing negative effects, primarily psychological (Marrocu et al , n d ) The incidence of adverse events is lower with microdosing compared to higher doses (Lea et al., 2020), though more research is needed to fully understand the long-term effects
Psychological Effects
While some users report positive effects of microdosing, such as reduced anxiety and improved mood, others experience heightened anxiety, irritability, or even more intense psychological effects such as the following:
1 Anxiety and paranoia: One study found that 20% of participants experienced paranoia while microdosing (Lea et al., 2020). Notably, this study found no direct correlation
between dose and anxiety levels, suggesting that factors other than dosage may contribute to these responses (Lea et al., 2020). Another study by Petranker et al. (2022) reported that 6 91% of psilocybin microdosers reported increased anxiety This is more likely to be the case for those with pre-existing mental health conditions such as schizophrenia or bipolar disorder (GCU, Lahore, Pakistan and Shabir, 2024).
2 Psychedelic effects: In some cases, individuals may experience mild psychedelic effects when microdosing, including perceptual distortions typically associated with regular doses (Hutten et al 2019) This can occur when a higher dose than intended is consumed, leading to unintended and undesirable psychological effects (M W Johnson et al., 2018; Lea et al., 2020).
3 Cognitive effects: 7 97% of psilocybin microdosers reported a reduced ability to focus (Petranker et al 2022) Some users report feelings of overstimulation, restlessness, or fatigue while microdosing (Polito & Liknaitzky, 2022; Petranker et al. 2022). Additionally, mental confusion, racing thoughts, and cognitive difficulties such as memory problems and reduced focus are common complaints among microdosers (Petranker et al., 2022). While many users report improved performance as a result of microdosing, double-blind research has indicated that some individuals experience reduced cognitive performance after microdosing (Rouaud, Calder, and Hasler 2024).
4 Negative mood and irritability: Mood fluctuations, irritability, and emotional overwhelm can also arise during or after microdosing sessions (GCU, Lahore, Pakistan and Shabir, 2024; Petranker et al., 2022). Some individuals may experience negative emotional states from microdosing, including feelings of frustration or sadness, which can detract from the intended benefits of the process.
5. Flashbacks: Although more commonly associated with higher doses of psychedelics, there have been reports of flashbacks following microdosing These episodes, which can involve sudden and unexpected recollections of the psychedelic experience, may contribute to psychological discomfort (Lea et al , 2020)
6 Unpredictable effects: The lack of standardization in microdosing practices, including variations in dosage and frequency, can result in unpredictable psychological responses. This inconsistency increases the likelihood of experiencing adverse psychological effects, such as anxiety, confusion, or mood instability (GCU, Lahore, Pakistan and Shabir, 2024).
Physiological Effects
Psilocybin microdosing can lead to various physical adverse effects. In one study 10.21% of psilocybin microdosers reported experiencing stomach pain, headache, sleep problems, or loss of appetite.(Petranker et al. 2022). A more comprehensive list of physiological effects follows.
1 Physical discomfort: Some psilocybin microdosers report general physical discomfort, including mild headaches and nausea (Polito & Liknaitzky, 2022) Gastrointestinal discomfort is also a common short-term effect, occurring shortly after ingestion (GCU, Lahore, Pakistan and Shabir, 2024)
2 Headaches: Headaches are one of the more frequently reported physiological side effects of microdosing (Polito & Liknaitzky, 2022). These headaches are typically mild but can be bothersome for some users
3. Sleep disturbances: Some users report experiencing difficulty falling or staying asleep after microdosing (Polito & Liknaitzky, 2022; Petranker et al., 2022). These sleep disturbances can interfere with daily functioning and may persist for a short time following the dosing.
4 Cardiovascular effects: Research into the cardiovascular impacts of psilocybin microdosing is still limited However, emerging studies suggest that microdosing could potentially affect cardiac function, particularly through the 5HT-2B receptor. This may contribute to risks like cardiac fibrosis, valvular heart disease, and QT-prolongation (Savides & Outhoff, 2024) However, there is no conclusive data on how microdosing specifically impacts blood pressure or heart rate (Polito & Liknaitzky, 2024).
5 Other physical symptoms: In addition to the more common effects like headaches and gastrointestinal discomfort, some participants report general physical symptoms, though these tend to be less frequent than those observed with LSD microdosing (Lea et al , 2020)
LSD Overview
Definition and Description
Lysergic acid diethylamide (LSD) is a synthetic psychedelic hallucinogen first synthesized in 1938 by Swiss chemist Albert Hofmann (Garcia-Romeu & Richards, 2018; Fuentes et al., 2020). LSD is entirely man-made and was initially developed for its potential medical uses Over the years, it has become widely known for its recreational use and potent hallucinogenic effects
Recreational LSD use has significantly increased in recent decades, with a 200% rise in consumption between the early 2000s and late 2010s (Baxter et al., 2024). This surge coincides with growing interest in its therapeutic potential. Among individuals who have used LSD in the past year, the majority report positive feelings and excitement about their first experience, with first-time users averaging around 21 years old and being predominantly male (Baxter et al , 2024) Most individuals are well-informed about the drug prior to use and engage in harm reduction practices, such as using it in familiar settings with close friends to enhance safety and minimize potential risks (Baxter et al., 2024).
Primary Classification
LSD is classified as a classical serotonergic psychedelic, meaning its effects are primarily mediated through the modulation of the serotonin system in the brain (Barrett et al., 2018; Forstmann & Sagioglou, 2021) LSD is an ergoline, a compound derived from lysergic acid, containing both phenethylamine and tryptamine groups, which contribute to its complex action
on the serotonin receptors (Lowe et al , 2022a) It acts as an agonist at the serotonin 2A (5-HT2A) receptor, which is believed to be central to its hallucinogenic and cognitive effects (M. W Johnson et al , 2019; Forstmann & Sagioglou, 2021) Although LSD is often referred to as a hallucinogen due to its ability to produce perceptual changes, the term "psychedelic" is considered more accurate by some researchers, as it better captures the substance's broader effects on consciousness and perception (Forstmann & Sagioglou, 2021; Fuentes et al , 2020)
Subjective Effects
LSD induces significant alterations in perception, cognition, and sensory experiences, leading to a temporary and reversible state of intoxication (Baxter et al., 2024). These alterations typically involve changes in time and identity perception, visual hallucinations, euphoria, and distorted sensory experiences, including delusions (Fuentes et al , 2020) The effects of an LSD trip can be divided into four phases: the onset phase (lasting 30-60 minutes), the peak phase (2-3 hours), the subsiding phase (another 2-3 hours), and the final phase, which marks the return to baseline (Petersen, Garg, & Ketha, 2020).
The subjective experience of LSD can be more intense compared to other illicit substances, and it may overwhelm users who are unprepared (Baxter et al , 2024) for its effects As with all psychedelics, the effects of LSD are highly individualized and influenced by factors such as the user's mindset, setting, and previous experiences (Baxter et al , 2024; M W Johnson et al , 2019)
Evidence for Therapeutic Use in Mental Health Setting
LSD has been explored for therapeutic purposes and is currently under investigation as a potential treatment for various psychiatric disorders (Baxter et al., 2024; Fuentes et al., 2020) as well as for conditions such as depression and anxiety (Baxter et al , 2024; Fuentes et al , 2020; Anderson et al., 2019).
Dosing
Microdosing involves taking very low doses of LSD, typically below the threshold required to induce hallucinogenic effects Common microdoses typically range from 5 to 20 mcg (Hutten et al , 2019; Family et al , 2020)
Macrodoses are usually 75 mcg or more, allowing users to experience the full range of psychedelic effects, such as altered perceptions and consciousness (Engel et al , 2024a; Lea et al., 2020).
For typical therapeutic or recreational use, the active dose range for LSD falls between 0 5 and 2 micrograms per kilogram (mcg/kg), or roughly 100 to 150 mcg per dose (Fuentes et al., 2020). Recreational doses generally vary from 50 to 150 mcg, but individuals may use doses anywhere from 10 mcg to over 400 mcg (Leonard, Anderson, and Klein-Schwartz, 2018)
The effects of LSD are dose-dependent, with the intensity of subjective experiences increasing as the dose rises. Positive effects tend to plateau at doses around 100 mcg, while higher doses may increase the likelihood of anxiety and ego dissolution (Holze et al , 2021) Individual factors such as tolerance, weight, and age also play a role in the drug’s effects, with variability in how users respond to different doses (Fuentes et al., 2020).
In clinical studies, doses such as 25, 50, 100, and 200 mcg have been explored to understand their subjective effects on healthy individuals (Holze et al., 2021).
Frequency
Microdosing is generally practiced on a regular schedule, with many users adopting a pattern of one day on, two days off Some individuals choose to microdose multiple times per month (Syed et al., n.d.; Family et al., 2020). This approach aims to provide subtle benefits without overwhelming the user, maintaining cognitive and emotional enhancements while avoiding significant perceptual shifts
On the other hand, macrodosing is typically done less frequently due to the intensity of the experience and the need for time to process and integrate the effects (Robinson et al , 2024; Gorman et al., 2021). Macrodoses are used to induce more profound psychedelic experiences, and these experiences often require longer recovery or reflection periods
LSD-Specific Risk Factors
LSD is considered to carry a relatively low risk of physiological harm, toxicity, overdose, and dependence when compared to other recreational drugs (Baxter et al , 2024; Martins et al , 2023) It does not typically cause physical dependence or withdrawal symptoms (Martins et al , 2023; Fuentes et al , 2020) However, repeated use can lead to tolerance, necessitating higher doses to achieve the same effect (Fuentes et al., 2020).
Please refer to the “Risk Factors of All Psychedelic Substances” section above for an exhaustive discussion of general psychedelic risk factors, all of which apply to the use of psilocybin. Psilocybin-specific risk factors are listed below.
Dosage and Potency
Higher doses of LSD are associated with a greater likelihood of adverse effects, including psychological distress and physiological discomfort For instance, the proportion of participants reporting "bad drug effects" increases from 9% at a 50 µg dose to 27% at 100 µg and 31% at 200 µg (Holze et al., 2022). Doses of 200 µg and above are typically considered high or capable of inducing "ego-dissolution," a state of intense disconnection from the self (Engel et al , 2024a) Extremely high doses, such as those over 500 µg, are reported to produce overwhelming effects that may lead to dangerous psychological outcomes (Bremler et al., 2023).
Psychological and Individual Factors
● Prior mental health conditions: Individuals with a history of mental health conditions, including psychosis, mania, or anxiety disorders, are at higher risk of experiencing adverse psychological reactions when using LSD. Those with a personal or family history of psychosis, bipolar disorder, or other psychotic disorders should be carefully screened before using LSD, as it may trigger or exacerbate symptoms of these conditions (Kopra et al., 2022; White et al., 2024). One study found that 37.5% of participants developed a psychiatric diagnosis following a negative psychedelic experience (Bremler et al., 2023), and individuals with a prior personality disorder diagnosis had a significantly higher risk of adverse responses (Marrocu et al., n.d.).
● Lack of experience: First-time users of LSD are especially vulnerable to experiencing overwhelming effects. A lack of familiarity with dosing and the unpredictable nature of LSD can increase the likelihood of a negative experience (Baxter et al , 2024) Additionally, users who lack knowledge about the potential effects of LSD may struggle to manage the psychological changes, increasing the risk of a "bad trip."
● Age: Younger individuals, particularly those under 25, are more likely to experience negative outcomes from LSD use One study found that 53% of individuals seeking emergency medical treatment (EMT) after using psychedelics were under 25 years old (Bremler et al , 2023) This may be due to factors such as lower risk awareness, impulsivity, and difficulty in emotional regulation among younger users (Marazziti et al., 2024)
● Prior negative experiences: Users who have previously had a challenging experience with LSD are more likely to experience adverse reactions in subsequent sessions (Aday et al., 2021). See “Risk Factors Associated with All Psychedelic Substances” above.
● Stressful life events: See “Risk Factors Associated with All Psychedelic Substances” above
Physical Health Conditions
While LSD is generally considered to have a low risk of causing physical harm, individuals with pre-existing physical health conditions, particularly those affecting the cardiovascular, neurological, or hepatic systems, may be at an increased risk of complications (Bender & Hellerstein, 2022) For example, individuals with cardiovascular issues such as high blood pressure or arrhythmias may experience exacerbated symptoms due to LSD’s effects on heart rate and blood pressure (Ghaznavi et al , 2025) People with a history of neurological disorders or conditions affecting the liver or kidneys may also face additional risks during the use of LSD, though these individuals are typically excluded from clinical trials for safety reasons.
Polysubstance Use and Drug Interactions
● Polysubstance use: The use of LSD in combination with other substances, such as alcohol, cannabis, or other psychedelics, can significantly increase the likelihood of adverse reactions. Polysubstance use often heightens the intensity of the experience and may lead to more unpredictable effects. Combining LSD with other drugs, especially
other serotonergic substances, can lead to an increased risk of negative psychological and physiological outcomes (Strassman, 1984).
● Drug interactions: The use of certain medications in combination with LSD can be particularly dangerous. Combining LSD with lithium has been associated with a higher risk of harm (Ghaznavi et al., 2025). Similarly, combining LSD with serotonergic drugs, such as SSRIs (selective serotonin reuptake inhibitors), can increase the risk of serotonin syndrome. This potentially life-threatening condition may cause severe symptoms like tachycardia, hypertension, seizures, and, in rare cases, fatalities (Sakai et al , 2024) It is essential for individuals to be aware of these interactions and avoid combining LSD with these medications unless medically supervised.
LSD-Specific Risk Factors Related to Routes of Administration
Oral administration: Oral administration is the most common and widely used method for consuming LSD. It is typically applied to blotter acid (small squares of paper), sugar cubes, or aspirin tablets or dissolved in liquids like water or alcohol (Abraham and Aldridge, 1993) to be ingested This route is generally considered safe in controlled settings, though it carries the risk of dosage uncertainty. Because the potency of LSD on blotter paper can vary significantly, users may unknowingly consume a higher dose than intended, leading to unpredictable effects The slower onset of effects compared to other methods is one of the main advantages, but it can also cause users to mistakenly take additional doses before the first one takes effect, increasing the risk of adverse psychological and physiological responses
Intravenous administration: Although intravenous (IV) administration of LSD is rare, it presents particular risks This faster onset of effects from the drug directly entering the bloodstream can lead to a more intense and overwhelming experience (Garcia-Romeu and Richards, 2018). Additionally, IV use makes it more challenging to control the dose accurately, increasing the potential for an overdose or a "bad trip " IV administration should only be done in a clinical or medically supervised environment due to these risks.
Ocular administration: Ocular administration of LSD has not been extensively studied The lack of information on this method's risks means it is not typically recommended outside controlled research or medical environments. The primary concerns with non-oral routes, such as unpredictable dosage and faster onset, apply to ocular administration as well
LSD-Specific Risk Factors Related to Quality, Sourcing, and Potential Contamination
Variability in Potency and Dosing Inaccuracy
One of the primary risks of illicit LSD is inconsistent dosing, particularly when the drug is administered via blotter paper. The LSD may not be evenly distributed across the paper, leading to "hot spots" with higher concentrations of the drug Conversely, some areas may contain little
or no LSD, resulting in an incomplete or weak experience (Miller et al , 2024) This uneven distribution can lead to unintentional overdose or less-than-expected effects. Furthermore, measuring doses outside of a controlled setting is challenging, particularly for those attempting to microdose. Even small deviations in dosage can have significant impacts on the drug’s effects, and without reliable home testing, users cannot be sure of the amount of LSD they are ingesting (Lea et al , 2020)
Sourcing from Unregulated Markets
LSD is often obtained from unregulated sources, which significantly increases the risk of exposure to impurities and inconsistent dosages. Illegally produced LSD lacks any regulatory oversight, making it impossible to verify the quality, purity, or potency of the substance As a result, users are exposed to greater risks of contamination, with some batches potentially containing dangerous substances The unregulated market, where most illicit LSD is sourced, further compounds this issue Without oversight or testing, it’s difficult for users to ascertain whether the LSD is pure or contaminated, leading to unpredictable effects and increasing the likelihood of adverse reactions (Bremler et al , 2023; Glynos et al , 2023)
Adulteration and Contaminants
Illicit LSD may be adulterated with other substances, such as substituted psychedelics (e.g., NBOMe family, DOx family) or atropine-like substances These adulterants may have similar effects but different safety profiles, increasing the risk of toxicity, overdose, or other severe reactions. For instance, NBOMe substances, often sold as LSD, have been associated with severe toxicity, including seizures, hallucinations, and fatalities (Malcolm & Thomas, 2022) Additionally, atropine-like agents could introduce unwanted physical side effects, making the experience even more dangerous (Sabé et al., 2024). In some cases, substances may be mislabeled or misidentified For example, LSD has been found in samples sold as cocaine (Hirschfeld et al , 2021) Additionally, The simultaneous use of other serotonergic substances with contaminated LSD increases the risk of serotonin toxicity (Hirschfeld et al. 2021; Malcolm and Thomas 2022)
Contraindications
Absolute Contraindications
These are conditions where LSD use is completely inadvisable due to the high risk of significant harm:
1. Severe organic disease: LSD use is contraindicated in individuals with severe organic diseases, particularly those involving neurological and cardiovascular systems, like organic-toxic cerebral disorder (Bodnár and Kakuk 2019) These conditions pose significant risks because the physiological effects that LSD can have, such as increased heart rate and blood pressure, can exacerbate underlying health issues (Fuentes et al , 2020)
2
Cardiovascular Issues: Individuals with severe cardiovascular conditions, including uncontrolled hypertension and arrhythmias, should avoid LSD. LSD can moderately elevate blood pressure and heart rate, which may trigger adverse events in individuals with pre-existing heart problems (Fuentes et al., 2020; Holze et al., 2021).
3. Active psychosis: LSD use is strictly contraindicated in individuals experiencing active psychosis The drug can worsen symptoms of psychosis, potentially triggering hallucinations or delusions that are difficult to manage in individuals with compromised mental health (Fuentes et al , 2020)
4 Pregnancy: Pregnant individuals are advised against using LSD due to the lack of research on its safety during pregnancy. The potential effects on fetal development and the risk of complications make pregnancy a contraindication (Fuentes et al , 2020)
5 Epilepsy: LSD is contraindicated for individuals with epilepsy, as it can increase the risk of seizures. The drug’s stimulating effects may trigger or worsen seizure activity, posing health risks (Fuentes et al , 2020)
6. Paranoid personality traits: Individuals with paranoid personality traits are advised to avoid LSD, as the drug’s effects can amplify feelings of suspicion, distrust, and anxiety which can lead to heightened paranoia and a negative psychological experience (Fuentes et al., 2020).
7 Current suicidality: LSD use is contraindicated for those experiencing acute suicidality The intense psychological effects of the drug may exacerbate feelings of hopelessness or despair, increasing the risk of self-harm (Holze et al., 2022).
Relative Contraindications
All of the relative contraindications for the use of LSD are discussed in the section above entitled “Risk Factors Associated with All Psychedelic Substances ” That said, the following contraindication is particularly important when considering the use of LSD:
History of Mental Health Issues: While not an absolute contraindication, individuals with a history of mental health issues, such as personality disorders, depression, or anxiety, are at a heightened risk of having a negative experience with LSD. For these individuals, careful screening, preparation, and support are essential if LSD use is considered (Marrocu et al , n d ; Sabé et al , 2024)
Adverse Events
Acute Adverse Effects
Psychological Effects
1 Anxiety and panic: Anxiety is one of the most frequently reported adverse effects of LSD use (Andersen et al. 2021; Family et al. 2022; Rossi et al. 2022) In a study of first-time LSD users, 64 1% experienced some level of fear, though it was generally mild and did not discourage further use (Baxter et al , 2024) Anxiety and panic reactions can escalate, particularly if users are unprepared for the intensity of the experience (Rossi et
al , 2022) In emergency medical treatment (EMT) cases, 69 6% of individuals reported anxiety or panic and 64.1% reported confusion (Kopra et al., 2022). These feelings often result from the altered state of consciousness and can be overwhelming for some
2. Psychotic symptoms: LSD can occasionally induce psychotic symptoms such as paranoia, hallucinations, and derealization. In one study, 1.3% of users reported persistent psychotic symptoms (Carhart-Harris & Nutt, 2010) These symptoms are rare but can overlap with the experience of a "bad trip" and cause significant distress for some individuals
3 Impaired cognition: LSD can impair cognitive functions, particularly attention, memory, and executive function. Users may struggle with concentration and problem-solving (Barber & Dike, 2023) Difficulty in processing information and executing tasks can make the experience disorienting and overwhelming
4. Ego dissolution: At higher doses, LSD can induce ego dissolution, which can be either positive or distressing While some may find this a transformative experience, for others, this loss of self may contribute to feelings of confusion and panic (Holze et al., 2021).
5 Reactivation of trauma: LSD can sometimes trigger the recall of past traumatic experiences, leading to heightened emotional distress Flashbacks of traumatic events, such as sexual assault, have been reported and can cause significant anxiety and psychological discomfort (Scala et al , 2024)
6 Suicidality and self-harm: Though rare, suicidal thoughts and self-harm can occur during or after LSD use, particularly in individuals with a history of mental health issues. In one study of EMT seekers, 20 6% of individuals reported thoughts or acts of self-harm (Kopra et al., 2022). Depression and suicidal ideation may arise during the acute phase of the experience.
Physiological Effects
1. Cardiovascular effects: LSD can cause moderate increases in heart rate and blood pressure In one study, peak heart rates over 100 beats per minute were observed in 25% of participants who took 200 µg of LSD (Holze et al., 2022). These cardiovascular changes are generally not life-threatening but could pose risks to individuals with pre-existing cardiovascular conditions (Romeo et al , 2024)
2. Increased body temperature: An increase in body temperature is another common physiological effect of LSD use For example, 34% of subjects who took 200 µg experienced peak body temperatures over 38°C (Holze et al , 2022) While not widespread, this increase can lead to hyperthermia if combined with physical activity or an overstimulating environment
3. Other physical symptoms: Other acute physical symptoms include sweating (26.5% of EMT seekers), palpitations (25 5%), difficulty breathing (20 6%), nausea and vomiting (17 6%), and headaches (Holze et al , 2022; Kopra et al , 2022) These symptoms tend to subside after the effects of LSD wear off.
4 Overdose: Although rare, there have been case reports of LSD overdose, leading to severe effects such as coma, hyperthermia, and bleeding (Leonard, Anderson, & Klein-Schwartz, 2018). In extreme cases, overdoses can lead to accidental death (Martins et al , 2023)
Severe adverse effects requiring emergency medical treatment following LSD use are rare, with only 0.5% of first-time users seeking help (Baxter et al., 2024). However, a review of studies on classic psychedelics found that serious adverse events (SAEs) were reported in approximately 4% of participants with pre-existing neuropsychiatric conditions, though concerns about underreporting persist (Hinkle et al., 2024).
Long-Term Adverse Effects
Psychological Effects
1 Hallucinogen Persisting Perception Disorder (HPPD): HPPD is one of the primary long-term adverse effects associated with LSD use. It is characterized by persistent perceptual distortions or hallucinations that occur long after the drug’s acute effects have worn off. HPPD is generally categorized into two types: Type I (transient) and Type II (chronic) (Aday et al , 2020) Symptoms of HPPD can include visual distortions such as flashes, “floaters”, afterimages, intensified colors, and palinopsia, as well as a range of dissociative experiences like depersonalization and derealization (Scala et al., 2024). HPPD is more commonly reported by users of illicit LSD, and its prevalence varies widely depending on the study For example, one study found that 15% of LSD users reported experiencing visual disturbances without any further drug use (John H. Halpern & Pope, 2003) However, when asked directly about HPPD symptoms, 10% of users reported long-term perceptual changes, though 73% did not consider these changes significant (Carhart-Harris & Nutt, 2010). While some individuals experience distressing symptoms, others report these phenomena as non-harmful or even meaningful (Baumeister, Tojo, & Tracy, 2015).
2 Flashbacks: Flashbacks, or the spontaneous re-occurrences of aspects of the LSD experience, are another potential long-term effect Flashbacks are sometimes linked to HPPD but can also occur independently. They can range from benign, fleeting experiences to more disruptive episodes Studies have found that between 10% and 35% of LSD users experience flashbacks, though not all of these are distressing or harmful (Kopra et al., 2022). In one study, 69% of former LSD users reported experiencing flashbacks (Larsen, 2016) Another study revealed that 66-79% of these individuals also experienced long-term anxiety alongside the flashbacks (Larsen, 2016). Yet another study claimed that around 15% of LSD users reported uncontrolled LSD-like experiences without any further drug use (John H Halpern & Pope, 2003)
3. Prolonged psychotic symptoms: LSD can sometimes trigger prolonged psychotic reactions, particularly in individuals with pre-existing mental health vulnerabilities These reactions can include paranoia, hallucinosis, and derealization, which may last for weeks or even months. One study found that 1.3% of LSD users experienced persistent psychotic symptoms (Carhart-Harris & Nutt, 2010), and another study found that 57% of individuals who had a bad experience with LSD developed extended psychosis (Rosenblat et al., n.d.). While these prolonged symptoms are rare, they are more common in uncontrolled settings or among individuals who have a psychiatric vulnerability (Carhart-Harris & Nutt, 2010). A review of studies on psychedelic use in
psychiatric patients found that psychosis rates following LSD use ranged from 0 08% to 4.6%, with higher rates typically observed in clinical populations (Johnson et al., 2008).
4 Anxiety and depression:Although LSD is not typically associated with long-term anxiety or depression, some users report a worsening of these conditions after LSD use, particularly if they have a history of mental health issues. In one study, 1.9% of LSD users reported experiencing an increase in anxiety, and 1 1% reported depressive symptoms (Carhart-Harris & Nutt, 2010). Anxiety symptoms may arise or intensify in the aftermath of an LSD experience, especially for individuals who experience a "bad trip" or have a predisposition to these conditions (Bremler et al , 2023)
5. Personality changes: Historical accounts suggest that chronic LSD use can lead to personality changes (J. H. Halpern and Pope 1999), but more recent studies have not confirmed these claims (Barnett et al. 2024). While there is no solid evidence to suggest that LSD causes permanent alterations in personality, some individuals may experience temporary shifts in their sense of self or behavior during or following intense psychedelic experiences (Barnett et al , 2024)
a. Self-harm and suicide: While rare, there are reports of self-harm and suicidality associated with LSD use One study found suicide attempts in 1 2 per 1000 patients, and completed suicides in 0.4 per 1000 (Johnson, Richards, & Griffiths, 2008). Although the causal link between LSD and suicidality is unclear, some individuals experience significant distress after their psychedelic experiences, particularly in cases where pre-existing mental health issues are present.
6 Psychiatric diagnoses: In some cases, individuals may develop psychiatric conditions following LSD use For example, a study found that 37 5% of participants were diagnosed with a psychiatric condition after a psychedelic experience (Bremler et al., 2023) A follow-up study 25 years after LSD treatment showed that 14% of patients developed schizophrenia or a delusional disorder, and 25% developed bipolar or depressive disorder (Larsen, 2016). It is important to note that such outcomes in the latter study were more common in individuals with pre-existing vulnerabilities or psychiatric conditions.
Physiological Effects
1. Cardiovascular issues: The long-term effects of LSD on the cardiovascular system are not well understood, but there is concern that prolonged or frequent use could contribute to cardiovascular issues Some studies have suggested that, as a 5-HT2B agonist, LSD could potentially contribute to valvular heart disease, particularly in individuals who engage in long-term microdosing (Bornemann, 2020)
2 Neurotoxicity: While LSD is generally considered to have low neurotoxicity, the long-term effects on the brain remain unclear. Some studies have suggested the potential for neurotoxic effects, while others have found no such evidence (Larsen, 2016).
Adverse Events of Microdosing
While microdoses of LSD are typically below perceptual thresholds, some users report experiencing noticeable psychoactive effects even at doses of 10-20 mcg (Murphy et al., 2024). At 25 mcg, these effects are clearer; as a result doses in the range of 21-30 mcg are sometimes categorized as "minidoses" rather than true microdoses (Holze et al., 2021).
Acute Adverse Effects
While microdosing LSD is generally intended to produce sub-perceptual effects, some users still report acute adverse effects. For instance, 20% of a sample of 1,116 microdosers reported adverse effects, although 30% reported no side effects at all (Wells et al , 2024) These effects can vary significantly depending on individual sensitivity, dosage, and other factors
Psychological Effects
Increased anxiety and psychological distress are common adverse effects of microdosing LSD. One study found that 81-93% of participants reported heightened anxiety during their experiences (Bremler et al., 2023). Additionally, some users experience emotional discomfort and racing thoughts (Wells et al., 2024; Hutten et al., 2019). In another study, a significant portion of LSD microdosers (9 69%) reported confusion, memory problems, and racing thoughts (Petranker et al., 2022). Overstimulation and difficulty concentrating have also been reported by some users (Lea et al , 2020) Dissociation or rumination was noted by 5 51% of microdosers (Petranker et al , 2022) Although these psychological effects are often transient, they can still be overwhelming for some users. A minority (1-3%) report that negative effects can last for days after dosing (Hutten et al , 2019)
Physiological Effects
Microdoses of LSD commonly lead to side effects such as headaches, cold sensations, and feelings of abnormality (Murphy et al , 2024; Andersen et al , 2021; Straumann et al , 2024) Notably, a study on low-dose LSD conditions noted that 12% of participants experienced general physiological discomfort (Bornemann, 2020) Around 10 59% of microdosers report experiencing restlessness or fatigue, while 7 67% report stomach pain, headaches, and sleep problems (Petranker et al., 2022). Other effects like loss of appetite and sleep disturbances have also been observed Studies indicate that microdosing LSD does not generally affect sleep quality or balance (Polito and Liknaitzky, 2024). The impact on heart rate and blood pressure is mixed, with some studies showing no significant changes and others noting increases (Polito and Liknaitzky, 2024)
Long-Term Adverse Effects
Long-term adverse effects of microdosing are rare, with 1-3% of users reporting negative effects lasting beyond the typical duration (Hutten et al , 2019) While most effects are acute and temporary, the long-term safety of microdosing has not been fully studied, and concerns about
potential cumulative or delayed effects, especially with regular use, remain These risks require further investigation.
Psychological Effects
1. Hallucinogen Persisting Perception Disorder (HPPD)
Though more commonly associated with full-dose psychedelic use, HPPD can potentially occur with microdosing. The risk of HPPD from microdosing is not fully understood, but it remains a consideration for long-term effects
2 Flashbacks
While flashbacks are rare and typically linked to higher doses, there have been reports of them following microdosing A small proportion of users (2%) have reported such incidents following mescaline use, and similar rates have been noted with psilocybin and LSD (Aday et al., 2020).
Physiological Effects
1. Cardiovascular Concerns
There are ongoing concerns regarding the long-term cardiovascular effects of microdosing LSD, particularly regarding the 5-HT2B receptor. This receptor has been implicated in valvular heart disease, and some studies suggest that even low doses of 5-HT2B agonists may negatively affect cardiac health (Bornemann 2020; Savides and Outhoff 2024). However, there is a lack of studies specifically addressing this issue.
Other Considerations:
Self-Medication and Efficacy
Some individuals use microdosing as a form of self-treatment for conditions like depression and anxiety, though this approach can lead to inconsistent results and potential risks (Kuypers, 2020). In many cases, the perceived lack of efficacy is the most common reason users discontinue microdosing, rather than negative side effects (Hutten et al , 2019)
Purity and Dose Inaccuracy
Microdosing LSD can be challenging due to the difficulties in ensuring consistent purity and concentration, especially when sourcing illegally LSD tabs can vary in potency or be contaminated with harmful substances (Lea et al., 2020). The lack of reliable dosing methods makes it hard for users to accurately assess the dose they are consuming, and some users report that it takes multiple attempts to find the right "sweet spot" for a microdose (Lea, Amada, and Jungaberle, 2020). Cutting LSD blotters to prepare microdoses can lead to inconsistent distribution, with some areas of the blotter containing more LSD than others (Miller et al , 2024) Volumetric dosing, where LSD is dissolved in liquid and measured by volume, can help ensure more consistent dosing (Miller et al., 2024).
Polydrug Use
Concurrent use of other substances such as alcohol and caffeine can alter the effects of LSD, making it difficult to isolate the specific impact of the microdose (Baxter et al , 2024) Some
users avoid microdosing when physically unwell or when consuming other substances (Miller et al., 2024).
Expectations and Psychological Impact
The expectation of experiencing psychedelic effects, even with low doses, can confound the results of microdosing, particularly in controlled studies where a microdose is used as a placebo condition (Bornemann, 2020)
Reasons for Discontinuation
Users most commonly discontinue microdosing due to a perceived lack of efficacy, with some studies noting a mismatch between expected and experienced effects (Hutten et al., 2019). Negative psychological or physical effects, especially when they occur together, can also lead users to stop microdosing (Hutten et al , 2019)
2C-X (2C-B, 2C-C, etc.) Family
Overview
The 2C family of psychedelics, which includes 2C-B, is a group of synthetic psychoactive drugs that produce hallucinogenic effects (Palamar and Acosta 2020; Páleníček et al 2013; M W Johnson et al. 2019). These substances are often encountered in the illicit drug market and are known for producing both psychedelic and entactogenic effects (Páleníček et al 2013)
Definition and Description
These substances were first synthesized by Alexander Shulgin in the 1970s (Palamar and Acosta 2020) 2C-B (4-bromo-2,5-dimethoxyphenethylamine) is the most well-known member of this family and is an analog of mescaline (Palamar and Acosta 2020). 2C psychedelics typically last for 6-8 hours, and experiences that result from their use are often described as being similar to but "lighter" or more manageable psychedelic experiences than those induced by other psychedelics like LSD (Palamar and Acosta 2020; Fradkin 2024). Users report effects such as visual distortions, enhanced sensory perception similar to that of ayahuasca and Salvia divinorum, emotional shifts/euphoria, and changes in thought processes (Palamar and Acosta 2020)
2C-B is found in the illicit drug market, often in tablet form with low falsification rates (Caudevilla Galligo et al, 2012). Many individuals use 2C-B in combination with MDMA, and, in a 2023 global survey, 2C-B showed a high rate of co-use among the 11 psychedelic substances, suggesting that co-use is common among users of this substance (Caudevilla Galligo et al, 2012)
Primary Classification
2C psychedelics are serotonergic psychedelics (Basedow and Kuitunen-Paul 2022; Marazziti et al. 2024a) that are often classified as non-classical psychedelics (Fradkin 2024). While they share some similarities with classical psychedelics like LSD and psilocybin, they exhibit some differences in their mechanisms (M. W. Johnson et al. 2019), including lower or even negligible activity at the 5-HT2A serotonin receptor (Fradkin 2024).
Subjective Effects
Evidence for Therapeutic Use in Mental Health Setting
Dosing
The typical dose range for 2C-B varies depending on the desired intensity of effects (Palamar and Acosta 2020) Common recreational doses range from 10 to 25 milligrams taken orally (Palamar and Acosta 2020, Caudevilla Galligo et al, 2012). Lower doses (1-5 mg) may produce subtle perceptual and emotional effects, while higher doses (20-30 mg) can induce more intense psychedelic experiences (Palamar and Acosta 2020)
Frequency
2c Family-Specific Risk Factors
It is important to note that there has been very limited research on 2C compounds. Research emphasizes more common psychedelics, so few definitive conclusions about the safety profile of the 2C family can be drawn. Please refer to the “Risk Factors of All Psychedelic Substances” section above for an exhaustive discussion of the general psychedelic risk factors that apply to this family of substances
The limited information available on 2c family-specific risk factors is outlined below:
● 2C-I can cause paranoid ideation, aggression, confusion, tachycardia, and hypertension (Baumeister, Tojo, and Tracy 2015). In some cases, emergency presentations, including renal failure, seizures, cardiac and respiratory arrest have been reported(Baumeister, Tojo, and Tracy 2015)
● Individuals who insufflate 2C-B risk severe neurological reactions, such as central serotonin syndrome, epileptic seizures, cerebral edema, and cerebral vasculopathy (Hirschfeld et al. 2021).
● Concurrent use of 2C-B with SSRIs, MAOIs, or certain triptans can increase the risk of serotonin toxicity(Hirschfeld et al 2021)
● A lack of access to accurate and evidence-based harm reduction information can increase the risks associated with 2C family drug use (Breeksema et al 2022; Kopra et al 2022; Pleet et al 2023) Inadequate preparation, insufficient knowledge about potential interactions, or an inability to recognize early warning signs of adverse events can all contribute to negative outcomes (Pleet et al 2023)
Risk Factors Related to Routes of Administration
There is insufficient research on risks related to the routes of administration for 2C substances However, it should be noted that 2C-B is typically administered orally, a route generally considered to be safe.
Risk Factors Related to Quality, Sourcing, and Potential Contamination
2C psychedelics are often sold illicitly in crystal or powder form, making it difficult to determine the correct dosage. This can lead to unintended overdosing (Baumeister, Tojo, and Tracy 2015; Hirschfeld et al 2021). There is also a risk of inconsistent experiences because the dosage can vary in different parts of the same batch (Hirschfeld et al 2021; Bremler et al 2023) This risk is heightened by reports of significant variations in the concentration of 2C-NBOMe and 25I-NBOMe within different sections of the same batch (Bremler et al 2023)
When 2C psychedelics are obtained through illicit means, the lack of quality control presents substantial risks due to the unknown purity of the substances (Bremler et al 2023; Glynos et al 2023) Users are at risk of consuming misrepresented drugs that may contain other, potentially more dangerous substances (Hirschfeld et al. 2021). Drugs sold as LSD or MDMA, for example, have been found to contain 2C psychedelics (Petranker et al 2022)
Contraindications
Absolute Contraindications
These are conditions where the use of 2C substances are completely inadvisable due to the high risk of significant harm:
1 Personal or family history of psychotic disorders: Individuals with a history of schizophrenia, bipolar disorder, or other psychotic disorders (Aday et al 2021; Ghaznavi et al. 2025; White et al. 2024; Bremler et al. 2023; Lowe et al. 2022), or those with a family history of such conditions (Aday et al 2021; Ghaznavi et al 2025; White et al 2024; Bremler et al. 2023; Lowe et al. 2022), should absolutely avoid 2C family substances Psychedelics can trigger psychotic episodes or worsen existing conditions in these individuals (Aday et al 2021; Ghaznavi et al 2025; White et al 2024; Bremler et al. 2023; Lowe et al. 2022; Henningfield et al. 2023; M. W. Johnson et al. 2019; Forstmann and Sagioglou 2021)
2 Cardiovascular conditions: Individuals with heart conditions, uncontrolled hypertension, or other cardiovascular issues (Fonzo et al. 2025) should avoid 2C family substances Psychedelics can elevate heart rate and blood pressure (Aday, Bloesch,
and Davoli 2020; Fonzo et al 2025), potentially putting these individuals at risk (Fonzo et al. 2025; Fuentes et al. 2020; Romeo et al. 2024; Kruger et al. 2024).
3 Concurrent use of serotonergic medications: Taking 2C family substances while on medications that affect serotonin levels, such as SSRIs, MAOIs, or certain triptans (Gomez-Escolar et al. 2024; Morton et al. 2023; Ashraf 2024; Malcolm and Thomas 2022) is absolutely contraindicated This combination significantly increases the risk of serotonin syndrome, a potentially life-threatening condition characterized by agitation, confusion, high fever, and seizures(Gomez-Escolar et al 2024; Ashraf 2024; Malcolm and Thomas 2022)
Relative Contraindications
These are conditions where psilocybin use may still be possible but requires careful evaluation, monitoring, and risk-benefit assessment:
1 History of anxiety or mood disorders: Individuals with a history of anxiety disorders, depression, or other mood disorders(Ona 2018) should exercise extreme caution if considering using 2C family substances These substances can exacerbate existing symptoms or trigger mood swings(Ona 2018) Careful consideration should be given to the potential risks and benefits, and use should only be undertaken with proper preparation, support, and in a controlled environment
2 Pregnancy and breastfeeding: The effects of 2C family substances on fetal development or breastfeeding infants are unknown. Use during pregnancy or breastfeeding is strongly discouraged (Fuentes et al 2020)
3. History of trauma: Individuals with a history of trauma (Ona 2018; Breeksema et al. 2022) should approach 2C family substances with caution Psychedelics can sometimes trigger the re-experiencing of traumatic events (Ona 2018; Breeksema et al 2022), leading to emotional distress and potential psychological harm(Breeksema et al. 2022). Therapeutic settings with trained professionals may be more appropriate for addressing trauma-related issues
4. Driving or operating machinery: Operating a vehicle or heavy machinery while under the influence of 2C family substances is extremely dangerous These substances impair judgment, coordination, and reaction time, significantly increasing the risk of accidents.
5. Use of lithium: The co-administration of classic psychedelics, such as 2C substances, with lithium is associated with a significantly increased risk of seizures (Nayak et al , 2021)
Adverse Events
The available sources offer limited specific information on the specific acute and long-term adverse effects of the 2C family of psychedelics. The research provided focuses primarily on more common psychedelics such as LSD and psilocybin, but their adverse effect most likely can be extrapolated to the 2C family
For an examination of these, please see the section entitled “Adverse Events Associated with All Psychedelic Substances” above.
DMT
Overview
Definition/Description
DMT is a naturally occurring tryptamine (Ramaekers, Reckweg, and Mason 2025a), an alkaloid that can be found in various Amazonian plant species (Ramaekers, Reckweg, and Mason 2025a) It is also found in some animals and can also be produced synthetically (Lancelotta and Davis 2020a). DMT is produced endogenously in mammalian brains (Barker 2022; Strassman and Qualls 1994) and is structurally similar to both serotonin and psilocybin (Rolando and Beccaria 2019). It is considered an endogenous neurotransmitter (Fradkin 2024; Ramaekers, Reckweg, and Mason 2025a) known to produce profound changes in consciousness, changes in cognition, heightened emotion, and increased self-awareness (Coyle, Presti, and Baggott, n.d.).
DMT has a long history of use by Indigenous peoples, particularly in South American shamanic rituals, and often in the form of a brew called ayahuasca (Rolando and Beccaria 2019; Forstmann and Sagioglou 2021), where it is combined with other molecules to make it orally bioavailable (James et al. 2024).
DMT is a potent, fast-acting psychedelic substance (Falchi-Carvalho et al 2024) which induces a transient and immersive altered state of consciousness (Luan et al 2024) Peak effects are seen within minutes of administration (Lancelotta and Davis 2020a; Strassman and Qualls 1994) and are generally short-lived, typically lasting between 10-60 minutes (Falchi-Carvalho et al. 2024).
The psychedelic experience of DMT is described as complex, dynamic and rich in visuals (Ramaekers, Reckweg, and Mason 2025a; (Luan et al 2024) It can produce "breakthrough" experiences, which are described as seemingly veridical interdimensional journeys (Fradkin 2024) characterized by extreme alterations in spatiotemporal perception and a sense of transportation through a boundless multiverse to "alien" realities (Fradkin 2024). DMT is also known to produce mystical experiences and feelings of ego death, characterized by a dissolution of one's sense of self (Ramaekers, Reckweg, and Mason 2025a) It also can lead to a sense of immersion into another world or dimension (Luan et al 2024) Some users report encounters with entities or sentient presences (Luan et al 2024)
DMT can be administered through various routes, including smoking/vaporizing, insufflation (snorting), intravenous (IV) or intramuscular (IM) injection, and orally though it requires a
monoamine oxidase inhibitor (MAOI) to be orally active (Eckernäs et al 2022) Each route leads to differences in onset and duration (Barker 2022; Neumann et al. 2024). When smoked or vaporized, the effects are felt within seconds to minutes (Falchi-Carvalho et al. 2024).
Intravenous administration also leads to rapid onset, within seconds to minutes (Falchi-Carvalho et al 2024)
DMT is unique among psychedelics due to its brief duration of action, extreme subjective intensity relative to dosage, and rapid metabolism (Fradkin 2024).
There is increasing interest in DMT for both recreational and therapeutic use (Rolando and Beccaria 2019) due to its rapid onset and the reliably produced mystical-type experience (Lancelotta and Davis 2020a). Currently, the prevalence of DMT use in the general population is relatively low (Lancelotta and Davis 2020a).
DMT is being investigated for its potential therapeutic benefits in mental health conditions, including treatment-resistant depression (Falchi-Carvalho et al 2024; Eckernäs et al 2022; Dourron et al 2023) Its rapid onset and short duration may make it a cost and time-effective approach to the treatment of mood disorders (Falchi-Carvalho et al. 2024) as well as a more scalable therapeutic option than longer-acting psychedelics (Dourron et al. 2023).
Primary Classification
DMT is classified as a classical serotonergic psychedelic (Forstmann and Sagioglou 2021; Fradkin 2024; Pilecki et al. 2021; Schlag et al. 2022) due to its agonistic activity at the serotonin 2A receptor (5-HT2A) (Forstmann and Sagioglou 2021; Fradkin 2024; Lowe et al 2022a; Vollenweider and Preller 2020). However, it also interacts with other serotonin receptors (Lancelotta and Davis 2020a). It is also considered a tryptamine (Fradkin 2024; Lowe et al. 2022a; Ramaekers, Reckweg, and Mason 2025a; Rucker et al 2024a)
In animal models, DMT is known to act as a non-selective 5-HT agonist, meaning it has activity at both the 5-HT1A and 5-HT2A receptors While DMT is considered a 5-HT2A agonist, the 5-HT1A receptor is also believed to play a role in its mechanism of action(Lancelotta and Davis 2020a; Dourron et al 2023)
While sharing properties with other psychedelics, DMT is considered an "atypical" psychedelic by some because of its unique subjective effects and relatively lower affinity for the 5-HT2A receptor, compared with 5-MeO-DMT (Dourron et al. 2023).
Dosing
Dosing for DMT varies significantly depending on the route of administration, the individual, and the desired effects. There is a steep dose-response curve (Lancelotta and Davis 2020a; Engel et al 2024a)
Oral DMT is inactive without the addition of a monoamine oxidase inhibitor (MAOI) (Engel et al 2024a). When taken orally with an MAOI, the total daily dose in ayahuasca can be 33-36 mg (Neumann et al 2024)
Studies using IV administration of DMT have used doses ranging from 0.05 to 0.4 mg/kg (Strassman and Qualls 1994). In one study, subjects received doses of 0.04 and 0.4 mg/kg intravenously (Strassman et al 1994) Doses of 0 2 mg/kg and higher elicited strong hallucinogenic effects (Strassman and Qualls 1994) Intravenous doses between 7 and 20 mg (approximately 0 1-0 28 mg/kg) have been used in studies with healthy volunteers, and these doses were well-tolerated (Engel et al. 2024a). When administered this way, effects begin almost immediately, peak after 2 minutes, and subside after 20 minutes (Engel et al. 2024a). Lower doses of 0.05 mg/kg and 0.1 mg/kg were mostly related to somaesthetic effects, while hallucinogenic effects were present after 0 2 mg/kg and 0 4 mg/kg were administered (Engel et al 2024a)
One study identified 1 mg as the lowest dose that could be used in research settings (Rucker et al. 2023).
Outside of research contexts, DMT is typically consumed via smoking or vaporizing (Engel et al 2024a) with typical recreational doses for inhalation around 6-20 mg (Engel et al 2024a) In one study, inhaled DMT doses ranged from 5/20 mg to 15/60 mg (Falchi-Carvalho et al. 2024).
DMT-Specific Risk Factors
Please refer to the “Risk Factors of All Psychedelic Substances” section above for an exhaustive discussion of general psychedelic risk factors, all of which apply to the use of DMT DMT-specific risk factors are listed below.
Dosage and Potency
Higher doses of DMT are associated with an increased risk of adverse events, including challenging experiences (Bremler et al 2023) Extreme dosing can indicate reckless behavior or underlying mental health issues (Bremler et al 2023)
Unknown quantities and purity are significant risk factors due to the illegal status of DMT and its lack of quality control, which can lead to accidental overdosing and toxicity (Bremler et al 2023; Malcolm and Thomas 2022).
Psychological and Individual Factors
A history of psychiatric illness or treatment is a risk factor for adverse reactions to DMT (Sabé et al 2024) Individuals with personal or family history of schizophrenia, schizoaffective disorder, psychotic depression or mania, or with ongoing manic or psychotic symptoms should avoid its
use (Sabé et al 2024; White et al 2024) Poorer premorbid adjustment increases the potential risk of adverse reactions to psychedelics such as DMT(Sabé et al. 2024).
Polysubstance Use and Drug Interactions
Simultaneous use of other drugs, including other psychedelics or substances of abuse, increases the risk of adverse events (White et al 2024; Rafael G Dos Santos et al 2018; Morton et al. 2023; Kopra et al. 2025). There are case reports of fatal adverse events when DMT is combined with other substances like MDMA or 5-MeO-DMT (Malcolm and Thomas 2022; Kopra et al 2025)
Combining DMT with certain substances, including some medications and harmala alkaloids found in ayahuasca, can lead to adverse reactions, including a potential risk of serotonin syndrome (Malcolm and Thomas 2022; Rafael Guimarães Dos Santos and Hallak 2024).
Combining DMT with substances containing high levels of tyramine can produce hypertension (Rafael Guimarães Dos Santos and Hallak 2024)
Behavioral Factors
● Lack of awareness/memory: Users of DMT may lack awareness or memory of their behaviors during the acute effects (Dourron et al. 2023). This can pose a risk if users engage in unsafe actions without realizing it (Dourron et al. 2023).
● Behavioral risks: DMT can cause odd behaviors such as muscle jerking, twitching, and abnormal vocalizations (Dourron et al 2023) Some users may exhibit behaviors such as vomiting, screaming, and taking off their clothes (Dourron et al 2023) There have also been anecdotal reports of highly sensual or even hypersexual experiences, such as spontaneous orgasms (Dourron et al. 2023). Self-injurious behavior has also been documented (Dourron et al. 2023).
● "Reactivations" or flashbacks: A significant risk associated with DMT is the potential for "reactivations" or flashbacks, where users re-experience the effects of the drug long after the acute experience has subsided (Dourron et al 2023) Flashbacks have been reported in 25% of participants with treatment-resistant depression across various dosing categories (Dourron et al. 2023). In a safety dose-finding study, some participants experienced flashbacks, hallucinations, "confusional states", and abnormal dreams (Dourron et al 2023) The mechanism of these reactivations is not fully understood but it may be related to epileptiform activity (Dourron et al 2023) Reactivations may be more common after vaporized administration (Dourron et al 2023)
● Risk of physical danger: DMT use might occasionally produce physical danger due to involuntary bodily movements (Dourron et al. 2023).
Contextual Factors
● Lack of proper preparation and guidance: Particularly for individuals new to DMT, this is a risk factor (White et al. 2024).
● Lack of trust: Lack of rapport with a session monitor can contribute to negative outcomes from DMT use (Ramaekers, Reckweg, and Mason 2025a).
Risk Factors Related to Routes of Administration
● Smoking or vaporizing: This method of DMT administration leads to a rapid rise in blood concentration, resulting in a very fast onset and intense effects (Fradkin 2024; Coyle, Presti, and Baggott, n.d.; Barker 2022; Dourron et al. 2023). This quick and powerful onset can be overwhelming and may increase the likelihood of a challenging experience, especially for inexperienced users (Fradkin 2024; Bodnár and Kakuk 2019) Smoking or vaporizing may be harsh and not always well-tolerated (Barker 2022), with the rapid onset of effects possibly leading to heightened anxiety or panic (James et al 2024; White et al 2024) Note that these methods can make it difficult to accurately measure the dose, potentially leading to accidental overdosing or unpredictable effects (Engel et al 2024a; Miller et al 2024) This is especially true in non-clinical settings where quality control and standardized dosing procedures are absent. Finally, vaporizing or smoking DMT may pose additional risks associated with respiratory irritation (Engel et al 2024a), such as airway hyperresponsiveness (Falchi-Carvalho et al 2024) One source recommends using electric combustion methods over flame combustion, and inhaling while seated (Engel et al 2024a)
● Intravenous (IV) administration: IV administration leads to the most rapid onset and intense effects (Barker 2022; Falchi-Carvalho et al. 2024). The intensity of the experience can be very high, similar to smoked or vaporized DMT, but the duration is typically shorter (Fradkin 2024; James et al 2024) This route may carry the highest risk of adverse cardiovascular reactions or other acute effects due to the rapid increase in plasma concentration (Barker 2022)
● Intramuscular (IM) Injection: IM administration results in a slightly slower onset compared to IV or inhalation (Barker 2022; Falchi-Carvalho et al. 2024). The effects are generally considered less intense for the IM route than for the IV route (Barker 2022)
● Intranasal delivery: Intranasal delivery has been shown to have a rapid absorption, with a time to peak plasma concentration of approximately 8-10 minutes It is considered a promising approach for parenteral applications (Rucker et al. 2024a). Intranasal administration of free-base DMT is inactive (Barker 2022)
● Oral Ingestion: This route of administration is not effective unless the DMT is combined with a Monoamine Oxidase Inhibitor (MAOI) such as in Ayahuasca (Engel et al 2024a; James et al 2024; Rafael Guimarães Dos Santos and Hallak 2024; Barker 2022) The combination of DMT and MAOIs carries a risk of potentially dangerous interactions including Serotonin Syndrome (Rafael Guimarães Dos Santos and Hallak 2024; Malcolm and Thomas 2022; Barker 2022)
Adverse Events Related to Quality, Sourcing, and Potential Contamination
Variability
Recreational use of DMT frequently involves higher doses, less control over substance purity, and less consideration of contextual factors (Hirschfeld et al. 2021; Gomez-Escolar et al. 2024; Bremler et al 2023) Illicitly produced DMT may have variable purity and potency, making it difficult to determine safe dosages (Glynos et al. 2023; Gomez-Escolar et al. 2024; Bremler et al. 2023; Edwards et al. 2023). This inconsistency increases the risk of unintended overdoses or unpredictable effects (Edwards et al 2023)
Sourcing from Unregulated Markets
DMT obtained from unregulated markets may not be what it is purported to be (Glynos et al 2023; Coyle, Presti, and Baggott, n.d.). Substances sold as "research chemicals" are particularly prone to misrepresentation and may contain different or unknown compounds (Coyle, Presti, and Baggott, n d ) DMT from unregulated sources may contain cheaper substitutes that have more dangerous side effects (Petranker et al. 2022).
Adulteration and Contaminants
Contamination of DMT with other substances is a significant concern (Glynos et al. 2023; Aakerøy et al 2021) This can occur due to inadequate cleaning of production equipment or negligence in illicit manufacturing (Aakerøy et al. 2021). Other substances such as amphetamines and MDMA have been found as trace contaminants in illicitly produced DMT (Aakerøy et al 2021) These can lead to unpredictable and potentially harmful effects (Hirschfeld et al. 2021; Glynos et al. 2023).
Lack of Information and Testing
Users often lack access to drug-testing services or kits, making it difficult to identify potential contaminants or determine the actual composition of the substance (Glynos et al 2023; Petranker et al 2022) Advanced analysis techniques like liquid or gas chromatography and mass spectrometry, which are needed for precise detection and quantification of substances, are not readily available to most drug-checking services(Hirschfeld et al 2021)
Contraindications
DMT-Specific Absolute Contraindications
These are conditions where DMT use is completely inadvisable due to the high risk of significant harm:
1 Unstable cardiovascular disease: Due to the potential cardiovascular effects of DMT, individuals with unstable or severe cardiovascular conditions should not use this substance (Falchi-Carvalho et al. 2024; Bodnár and Kakuk 2019).
2 Pregnancy: This is an absolute contraindication to DMT use (Bodnár and Kakuk 2019) Animal models using higher doses of ayahuasca have shown abortifacient and teratogenic effects (White et al 2024)
3 Epilepsy: This condition is considered an absolute contraindication (Bodnár and Kakuk 2019).
4 Personal history of psychosis or schizophrenia: Individuals with a personal history of psychotic disorders are generally considered to have an absolute contraindication to DMT use due to the risk of exacerbating these conditions or triggering a psychotic episode (Henningfield et al. 2023; Rosenblat et al. 2023; Bodnár and Kakuk 2019; Sabé et al. 2024; White et al. 2024).
5 Family history of psychosis/bipolar disorder: Individuals with a first or second-degree relative with psychosis or bipolarity are typically excluded from clinical trials due to the elevated risk (Rosenblat et al 2023)
6 Organic-toxic cerebral disorder: This diagnosis is an absolute contraindication to DMT use (Bodnár and Kakuk 2019).
7 Concomitant use of MAOIs: The use of any MAOIs, including many antidepressants, is an absolute contraindication, due to the risk of serotonin syndrome (Rafael Guimarães Dos Santos and Hallak 2024) unless specifically part of a controlled therapeutic protocol (Barker 2022)
DMT-Specific Relative Contraindications
These are conditions where DMT use may still be possible but requires careful evaluation, monitoring, and risk-benefit assessment:
1 Unstable medical conditions: Individuals with unstable medical conditions, such as uncontrolled respiratory issues, may be at higher risk for complications during DMT use (Marazziti et al. 2024).
2. Non-psychotic bipolar disorder: While not an absolute contraindication, a cautious approach is warranted with this condition as there is documented evidence of a switch into mania after psilocybin use, and a similar risk may exist with DMT (Morton et al 2023).
3 Pre-existing mental health conditions: While DMT is being explored for the treatment of mental health conditions, it may not be appropriate for individuals with unstable mental health conditions or those who are not under appropriate supervision (Vollenweider et al. 1998). Some proponents of psychedelic-assisted therapy suggest it should only be used for reactive disorders (such as PTSD) since it can exacerbate distress in those with a prior psychiatric history (Parrott 2014)
4 History of anxiety disorders: While some studies suggest DMT has potential in reducing anxiety disorders, it may also cause transient anxiety in users. The risk for a negative reaction should be carefully assessed (Ramaekers, Reckweg, and Mason 2025a; White et al 2024)
5. Family history of psychotic disorders: Individuals with this background should proceed with caution, as this history increases the risk of adverse psychological reactions (Rafael G Dos Santos et al 2018)
6. Breastfeeding: It is not known whether DMT passes into breast milk and its effect on the infant; therefore, use should be avoided during breastfeeding (Marazziti et al 2024)
Adverse Events
For a list of potential adverse events involved with the use of all psychedelic substances, including DMT, please see the section entitled “Adverse Events Associated with All Psychedelic Substances” above The list below is confined to DMT-specific adverse effects
In general, clinical trials have not reported serious adverse events associated with DMT use (Falchi-Carvalho et al 2024; Hinkle et al 2024) DMT is considered to have a low toxicity, and deaths from DMT are rare (Neumann et al 2024; Kopra et al 2025)
Acute Adverse Effects of DMT
Psychological Effects
● Anxiety: Transient anxiety is frequently reported, particularly prior to administration and during the onset of drug effects (White et al. 2024). One study reported that during extended DMT experiences, anxiety ratings remained low (Luan et al 2024)
● Behavioral changes: Odd behaviors like abnormal vocalizations, screaming, and removing clothes have been observed (Dourron et al. 2023). There are also reports of spontaneous orgasms and, rarely, self-injurious behavior (Dourron et al. 2023).
● Altered perceptions: These include visual illusions, hallucinations, and body image distortion (Falchi-Carvalho et al 2024; Barker 2022) Some users may experience a "white-out" or a loss of behavioral control (Dourron et al 2023)
● Challenging experiences/negative emotions: DMT can produce intense negative emotions or challenging experiences as part of the psychedelic state( Ramaekers, Reckweg, and Mason 2025a) These experiences, while often described as cathartic, can be psychologically distressing (Ramaekers, Reckweg, and Mason 2025a).
● Paranoia: Brief paranoia can occur during DMT sessions, though this affects fewer than 10% of patients (Sabé et al 2024)
● Altered perception: Users may experience derealization, a sensation of losing connection with reality (Bremler et al 2023)
● Loss of awareness: Users often lack awareness or memory of their behavior during the acute effects of DMT (Dourron et al. 2023).
Physical Effects
● Increased heart rate and blood pressure: DMT can cause increases in blood pressure and heart rate during the psychedelic experience (Ramaekers, Reckweg, and Mason 2025a; Strassman and Qualls 1994; Falchi-Carvalho et al 2024; Strassman and Qualls 1994). These effects are generally mild and transient, but real-time cardiovascular monitoring is critical due to DMT's sympathomimetic effects (Falchi-Carvalho et al 2024) In one study, heart rate increases habituated within 15 minutes, suggesting the physiological safety of extended DMT infusions (Luan et al. 2024)
● Bradycardia: Asymptomatic bradycardia was observed in one case (White et al 2024)
● Headache: Transient headaches are sometimes reported during the onset and after resolution of DMT effects (White et al. 2024; Rucker et al. 2023).
● Nausea and vomiting: Nausea and vomiting are commonly reported adverse effects of DMT, particularly when consumed orally as part of ayahuasca (White et al. 2024; Rucker et al. 2023).
● Neuromuscular effects: Tremors, muscle fasciculation, muscle jerking, and twitching can occur (Falchi-Carvalho et al. 2024; Dourron et al. 2023) Fainting and fits/seizures are rare but have been reported (White et al 2024)
● Respiratory irritations: Inhaled DMT can irritate the airways, causing coughing during inhalation and mild hoarseness (Falchi-Carvalho et al. 2024); however, in general, respiratory effects have been less frequently reported (White et al. 2024).
● Temperature regulation: Some individuals may experience feeling cold, even if objective measurements of body temperature don't change (Falchi-Carvalho et al 2024) DMT can also elevate body temperature (Strassman and Qualls 1994)
● Other: Other physiological effects include pupil dilation and increased sweating (Strassman and Qualls 1994; Papaseit et al. 2018).
Long-Term Adverse Effects of DMT
Psychological Effects
● Flashbacks/reactivations: Subacute effects of DMT, occurring in the days following dosing, may include flashbacks or reactivations, which are brief (on the order of seconds) re-experiences of the drug's effects (Ramaekers, Reckweg, and Mason 2025a; Ortiz Bernal et al 2022) They can be spontaneous and may involve visual, auditory, or emotional components (Dourron et al 2023; Ortiz Bernal et al 2022) These are a notable concern, occurring more frequently with DMT than with typical psychedelics (Dourron et al 2023) The prevalence of flashbacks is highly variable across studies, ranging from 15% to 77% of psychedelic users (Ona 2018; Pflieger 2005) Estimates of reactivation prevalence specifically in naturalistic settings range from 27% to 73% (Dourron et al 2023), while in clinical settings, flashbacks were reported in 25% of participants in one study (Dourron et al. 2023). While most reactivations are reported as positive or neutral, some can be negatively valanced (Dourron et al 2023; Ortiz Bernal et al 2022) A minority of users report distress that prompted psychological help (Dourron et al. 2023). There are some reports of continued flashback experiences months after the initial use (Ortiz Bernal et al 2022) Anecdotal reports suggest that reactivations may occur more frequently at night or when drifting off to sleep (Ortiz Bernal et al. 2022).
● Psychotic symptoms/disorders: While research suggests the risk of psychosis from DMT alone is minimal (Sabé et al 2024), some cases of psychotic symptoms or disorders have been observed, mainly in individuals with pre-existing psychiatric vulnerabilities, a family history of psychosis, or when DMT is used concurrently with other substances (White et al. 2024).
● Anxiety and depression: Some users report anxiety and depression as long-term side effects (Ona 2018).
● Derealization: Some users report a long-term feeling of derealization or losing connection with reality after their DMT experience (Bremler et al. 2023).
● Potential for sensitization: Repeated administration of DMT might lead to sensitization, increasing its effects, rather than tolerance, which is more common with other substances (Dourron et al 2023)
● Cognitive impairment: There is currently no evidence to suggest that the use of DMT results in long-term cognitive deficits (White et al. 2024).
● Dependence/addiction: The dependence potential of DMT is considered minimal (Sabé et al 2024) Classic psychedelics, including DMT, have low abuse potential due to the rapid development of tolerance (Ghaznavi et al. 2025), and self-administration studies in animals with classic psychedelics have generally been unsuccessful, supporting the low risk of addiction (Ghaznavi et al. 2025). Hallucinogen use disorder (HUD) is rare, with a lifetime prevalence of 0 6% and a 12-month prevalence of 0 05% in the general population, and among hallucinogen users, 6 4% and 8 1% developed lifetime and 12-month HUD, respectively (Ghaznavi et al. 2025).
● Adverse Events Requiring Professional Support: Approximately 12% of ayahuasca users have reported seeking professional mental health assistance for adverse effects (Evans et al. 2023; Robinson et al. 2024).
5-MEO-DMT
Overview
Definition and Description
5-MeO-DMT, or 5-Methoxy-N,N-dimethyltryptamine, is a psychoactive tryptamine (Rucker et al. 2023) found in various plants, fungi, and animals (Engel et al. 2024a; Lowe et al. 2022a; Ramaekers, Reckweg, and Mason 2025a) and, notably, in high concentrations in the venom of Incilius alvarius, the Sonoran Desert toad (Dourron et al 2023) It can also be synthesized
5-MeO-DMT is known for its rapid onset and short-acting psychedelic effects (Rucker et al 2023). Its unique pharmacology leads to subjective effects that are not commonly associated with classic psychedelics (Dourron et al. 2023).
In the U S , it is estimated that only 1 2% of adults reported any psychedelic tryptamine use (including DMT and 5-MeO-DMT) between 2009 and 2013 Surveys have shown that most 5-MeO-DMT users are Caucasian males with a history of using other substances (Lancelotta and Davis 2020b).
○ Global prevalence data is limited due to a lack of inclusion in epidemiological surveys (Davis et al., 2018).
○ When included in surveys, 5-MeO-DMT is often grouped with other psychoactive tryptamines and synthetic cathinones, making specific prevalence estimates difficult to obtain (Davis et al , 2018)
○ One survey study indicated that the use of 5-MeO-DMT is infrequent, with most respondents reporting use once a year or less (Davis et al , 2018)
○ The primary motivation for using 5-MeO-DMT is spiritual exploration. (Davis et al., 2018).
○ Users also report using it for therapeutic purposes, such as improving symptoms related to PTSD, depression, anxiety, and addiction (Davis et al , 2018)
Primary Classification
5-MeO-DMT is classified as an atypical psychedelic (Dourron et al. 2023). While it shares some characteristics with classic serotonergic psychedelics, such as the ability to induce altered states of consciousness, it has a distinct pharmacological profile (Dourron et al 2023) Unlike typical psychedelics, which primarily act as agonists at the 5-HT2A receptor (Marazziti et al 2024; Forstmann and Sagioglou 2021), 5-MeO-DMT has a higher affinity for the 5-HT1A receptor (Dourron et al. 2023). It is a non-selective serotonin agonist active at both 5-HT1A and 5-HT2A receptors. The high selectivity for 5-HT1A receptors over 5-HT2A receptors suggests that 5-MeO-DMT may have a different mechanism of action compared to typical psychedelics (Dourron et al 2023)
Subjective Effects
5-MeO-DMT can produce intense experiences described as more profound than other psychedelics. These may include ego dissolution, mystical-type experiences, "peak experiences," and a sense of loss of control (Dourron et al 2023; Rucker et al 2024a) They can include a sense of "nothingness" or "whiteout," often described as an experience beyond ordinary comprehension (Dourron et al 2023) These experiences may involve a subjective sense of a void and/or amnesia of the experience (Dourron et al. 2023). Despite these differences, 5-MeO-DMT can also induce mystical experiences in some contexts, comparable to those of psilocybin (Dourron et al. 2023; Rucker et al. 2023). Some users may feel as if they are dead or dying or have a profound experience of their own death (Lancelotta and Davis 2020b) The importance of the differences between the subjective experience of 5-MeO-DMT and other psychedelics is not yet fully understood (Rucker et al 2024a)
Evidence for Therapeutic Use in the Mental Health Setting
Despite its unique effects, 5-MeO-DMT is being investigated for its therapeutic potential, particularly in treatment-resistant depression (Dourron et al 2023) Some studies suggest it may reduce symptoms of depression for at least one week (Dourron et al 2023)
Dosing
There is less data available on 5-MeO-DMT compared to other psychedelics, and dosing studies have not been done in human volunteers, making it difficult to define safe dosage ranges (Engel et al 2024b) However, clinical studies have evaluated intranasal doses ranging from 1mg to 12mg (Rucker et al 2023) Subjective effects and intensity increase with the administered dose (Rucker et al 2023) One study states that recreational doses ranged from 6-20 mg when inhaled and 0.7 - 3.1 mg when injected intravenously (Engel et al. 2024a). The steep dose-response curve of 5-MeO-DMT may increase risks for those who choose to consume this substance (Lancelotta and Davis 2020b)
5-MEO-DMT-Specific Risk Factors
Please refer to the “Risk Factors of All Psychedelic Substances” section above for an exhaustive discussion of general psychedelic risk factors, all of which apply to the use of 5-MeO-DMT. 5-MeO-DMT-specific risk factors are listed below.
5-MeO-DMT Specific Risk Factors
Dosage and Potency
● Potency and overdose risk: 5-MeO-DMT is a highly potent psychedelic, and its effects can be rapid and intense with a short duration (Engel et al. 2024a). Dosing is challenging due to the lack of research and standardized protocols, and reported dosages vary considerably Many users are also uncertain about the dose they take (Bremler et al 2023).
Psychological and Individual Factors
● Intense physical and psychological reactions: 5-MeO-DMT can produce intense body reactions that may cause fear or panic, making it essential that a trip sitter has relevant experience (Engel, Thal, and Bright 2022). The psychological experiences can also be difficult to predict, and although intense experiences are sometimes reported to be cathartic, they can also cause psychological distress (Ramaekers, Reckweg, and Mason 2025a).
● Potential for loss of control and unpredictable behavior: 5-MeO-DMT can cause unexpected behaviors such as vomiting, screaming, or removing clothes(Dourron et al 2023). Users may also have a lack of awareness or memory of their behaviors during the acute effects (Dourron et al. 2023). There are anecdotal reports of highly sensual or hypersexual experiences (Dourron et al 2023) Some users report physical danger due to involuntary movements (Dourron et al 2023)
● Intensity of experience: Many users describe the subjective effects of 5-MeO-DMT as "more intense" than other psychedelics (Dourron et al 2023) This intense experience
could be a risk factor for those unprepared for the effects, potentially leading to challenging experiences such as anxiety, fear, and the feeling of being close to death (Lancelotta and Davis 2020a).
● Variability in response: The intensity of the psychedelic experience following 5-MeO-DMT administration can vary significantly between individuals (Ramaekers, Reckweg, and Mason 2025a).
● "Reactivations" or flashbacks: These are reported more frequently with 5-MeO-DMT than other psychedelics (Dourron et al 2023), a phenomenon that requires further investigation (Dourron et al 2023; Ortiz Bernal et al 2022) These reactivations may be related to potential epileptiform activity in the temporal lobes (Dourron et al. 2023). The frequency of reactivations after 5-MeO-DMT use in naturalistic settings ranges from 27-73% (Dourron et al. 2023). In clinical trials, 25% of participants reported flashbacks (Dourron et al 2023)
● Strong association with need for care: 5-MeO-DMT is the substance most strongly associated with a perceived need for care, likely due to the elevated risk of contraindications (Engel et al 2024a)
● Sensitization: Unlike typical psychedelics, which may lead to tolerance, there is some evidence that repeated administration of 5-MeO-DMT may lead to sensitization, meaning that the effects become stronger with repeated use (Dourron et al. 2023). This may contribute to unpredictable outcomes, particularly when higher doses are taken after previous exposures(Dourron et al 2023)
● Individual differences in metabolism: Individual genetic variations in cytochrome P450 enzymes can affect how 5-MeO-DMT is metabolized(Dourron et al 2023) These differences can lead to variations in drug exposure and susceptibility to adverse effects (Dourron et al. 2023). Genetic polymorphisms may also contribute to the build up of bufotenine or other metabolites, causing unexpected effects (Dourron et al. 2023).
Physical Health Conditions
● Potential for seizures: 5-MeO-DMT’s unique pharmacology may contribute to d "white-outs" and potentially increase the risk of seizure-like activity (Dourron et al 2023) There have been reports of muscle jerking, twitching, and abnormal vocalizations, as well as occasional self-injurious behavior (Dourron et al. 2023). It's theorized that 5-MeO-DMT's action on 5-HT1A receptors in the medial temporal lobes could precipitate epileptiform activity (Dourron et al 2023) Animal studies and some case reports have documented seizure-like behaviors with 5-MeO-DMT (Dourron et al. 2023).
Polysubstance Use and Drug Interactions
● Pharmacodynamic interactions: 5-MeO-DMT is a non-selective serotonin receptor agonist, with affinity for other receptors and serotonin and norepinephrine transporters (Engel et al. 2024a). This can lead to unpredictable interactions, especially in combination with other substances Specifically, when combined with MAOIs (Monoamine Oxidase Inhibitors), 5-MeO-DMT can lead to potentially fatal serotonin
syndrome (Malcolm and Thomas 2022) Harmala alkaloids, found in ayahuasca, inhibit MAO and CYP2D6, increasing 5-MeO-DMT exposure up to sixfold (Malcolm and Thomas 2022) There have been case reports of serotonin toxicity and death when 5-MeO-DMT has been combined with harmala alkaloids and other tryptamines (Malcolm and Thomas 2022). While classical tryptamines have a favorable safety profile with MAOIs, this does not necessarily extend to all tryptamines such as 5-MeO-DMT (Malcolm and Thomas 2022).
Risk Factors Related to Routes of Administration
5-MeO-DMT's route of administration significantly influences its risk profile due to variations in absorption rates, bioavailability, and the resulting intensity and duration of effects (Rucker et al. 2024b) Note that concentrated and lesser known psychedelics consumed via routes other than oral administration are seen as more requiring of psychedelic care (Engel et al 2024a)
Inhalation (smoking/vaporizing)
● Rapid onset and intense effects: The most common method of 5-MeO-DMT consumption is through inhalation or vaporization, leading to a rapid onset of effects within seconds to a minute The peak effects typically occur within 5 to 20 minutes and resolve within 45 to 90 minutes (Rucker et al. 2023). Other research has found inhaled 5-MeO-DMT has a rapid onset, with effects peaking within 2-5 minutes and lasting 15-20 minutes (Engel et al 2024b) This rapid onset can lead to a more intense experience, which may increase the risk of anxiety, fear, and other adverse psychological reactions (Ramaekers, Reckweg, and Mason 2025b)
● Dosing challenges: Inhaled doses can be difficult to measure accurately, leading to variability in the amount of 5-MeO-DMT consumed. This uncertainty increases the risk of unintentional overdosing or unexpectedly strong experiences (Engel et al 2024b)
● Potential for lung irritation: Inhalation can cause irritation to the respiratory system, particularly if the compound is not pure or is combusted improperly (Engel et al. 2024b). Some users may experience coughing or other forms of respiratory discomfort (Rucker et al. 2024b).
● Higher risk of reactivations: Reactivations, or brief sensory re-experiences of the drug, have been reported more often after inhaled use compared to intramuscular administration (Ramaekers, Reckweg, and Mason 2025b). Vaporized administration of 5-MeO-DMT was also associated with greater redosing, which could contribute to a kindling-like effect that may increase the risk of reactivations (Dourron et al 2023)
Intranasal (Insufflation)
● Rapid onset: Intranasal administration also leads to a rapid onset, with peak effects occurring within 5-7 minutes and lasting up to 45 minutes (Engel et al. 2024b). The time to maximum concentration (Tmax) ranges from 6 to 15.2 minutes, depending on the dose (Rucker et al 2023) This rapid onset, while not as immediate as inhalation, still
poses a risk of intense experiences and potentially adverse reactions, particularly in those with limited prior psychedelic experience.
● Nasal discomfort: Common adverse effects include nasal discomfort, nausea, and headache (Rucker et al 2024b)
● Variable absorption: The rate and extent of absorption through the nasal mucosa can vary between individuals, leading to inconsistent effects (Ermakova et al., 2021; Erowid, 2015)
● Risk of inaccurate dosing: Measuring doses accurately for insufflation can be challenging, and variations in technique can lead to unpredictable effects and the potential for overdosing (Erowid, 2015)
Intravenous Injection
● Extremely rapid onset: Intravenous (IV) administration of 5-MeO-DMT leads to an almost immediate onset of effects (Reckweg et al., 2022). This can result in highly intense experiences which may be more likely to induce anxiety or other adverse reactions and can be particularly dangerous due to the speed and intensity of the effects (Reckweg et al., 2022).
● Higher risk of overdose: The rapid and complete bioavailability of IV administration (Reckweg et al., 2022) makes it easier to overdose, and increases the need for precise measurement
Oral Ingestion
● Generally inactive without MAOI: 5-MeO-DMT is generally inactive when taken orally without a Monoamine Oxidase Inhibitor (MAOI) (Rafael Guimarães Dos Santos and Hallak 2024; Lowe et al. 2022b; Rucker et al. 2024b). This is because the compound is rapidly broken down by enzymes in the gut and liver (Lowe et al 2022a; Rucker et al 2024a) However, when combined with MAOIs, there is a significantly increased risk of serotonin toxicity (Malcolm and Thomas 2022). This risk is particularly pronounced with irreversible MAOIs, but can also occur with reversible MAOIs (Malcolm and Thomas 2022).
Other Routes (Rectal, Sublingual, Intramuscular)
● Limited Data: There is less information available regarding the risks associated with rectal, sublingual, and intramuscular administration of 5-MeO-DMT (Rucker et al 2024a)
● Intramuscular administration has been reported as having a lower prevalence of reactivations relative to inhaled administration (Ramaekers, Reckweg, and Mason 2025a)
● Sublingual administration of 5-MeO-DMT is generally associated with lower subjective intensity (Engel et al 2024a)
Adverse Events Related to Quality, Sourcing, and Potential Contamination
The quality, sourcing, and potential contamination of 5-MeO-DMT significantly influence its risk profile. These factors can lead to unpredictable and potentially dangerous effects due to variations in potency, the presence of adulterants, and inconsistent chemical composition (Glynos et al. 2023; Hirschfeld et al. 2021; Nichols and Barker 2016; Petranker et al. 2022).
Variability in Potency and Dosing Inaccuracy
● Dosing uncertainty: Without regulatory oversight, the dose of 5-MeO-DMT in a product may vary significantly (Lancelotta and Davis 2020b).This lack of standardization makes it difficult to gauge how much 5-MeO-DMT is being consumed, increasing the risk of overdose or adverse events (Lancelotta and Davis 2020b)
● Purity variability: The purity of 5-MeO-DMT can vary significantly, especially when sourced from unregulated markets This variability can lead to unpredictable effects, making it difficult for users to determine a safe dose (Glynos et al. 2023; Edwards et al. 2023) and therefore increasing risk (Coyle, Presti, and Baggott, n.d.). The process of extracting 5-MeO-DMT from plants and animals can also affect the purity and presence of contaminants (Lowe et al 2022a; Ramaekers, Reckweg, and Mason 2025a; Rucker et al 2024a) These sources include the venom of the Sonoran desert toad (Ramaekers, Reckweg, and Mason 2025a; Rucker et al 2024a) and plant sources, such as A peregrina (yopo) and Virola theiodora (Lowe et al. 2022a). There are differences in reported experiences when using toad-derived 5-MeO-DMT versus synthetically produced 5-MeO-DMT, suggesting that sourcing is a key factor to consider (Ortiz Bernal et al 2022)
● Variability in 5-MeO-DMT sources: 5-MeO-DMT can be derived from natural sources (such as the Incilius alvarius toad) or produced synthetically (Dourron et al 2023) Each of these source types introduces unique risk factors.
■ Toad-derived 5-MeO-DMT (Bufotoxin): The venom of the Incilius alvarius toad, often called bufotoxin, contains 5-MeO-DMT However, it also contains bufotenine and other compounds (Dourron et al 2023)
● Variable concentrations: The concentration of 5-MeO-DMT in toad venom can vary significantly, which makes dosing inconsistent and dangerous (Neumann et al. 2024).
● Presence of bufotenine: Bufotenine is a related compound that also has psychoactive properties and can cause adverse effects (Dourron et al 2023) Although 5-MeO-DMT is metabolized into bufotenine, it's not clear if the presence of bufotenine in toad secretions significantly impacts the effects The amount of bufotenine that results from the metabolism of 5-MeO-DMT might not produce notable effects, and therefore, differentiating between toad secretions and synthetic versions of 5-MeO-DMT based on the presence of bufotenine may be irrelevant (Dourron et al
2023) However, there are potential individual differences in how people metabolize 5-MeO-DMT, which could influence the effects of bufotenine (Dourron et al. 2023).
● Ethical and environmental concerns: Harvesting toad venom for recreational use raises concerns about the ethical treatment of the toads and the potential harm to their populations
● Synthetic 5-MeO-DMT: Synthetic 5-MeO-DMT is produced in labs, which can lead to its own set of risks:
○ Impurities: The synthetic process can leave behind impurities and byproducts if not carried out properly (Bremler et al 2023)
○ Adulteration: There is risk of intentional adulteration with other substances, which could be dangerous
○ Mislabeling: Synthetic versions may be misrepresented or mislabeled, leading to users unknowingly consuming another substance (Bremler et al 2023)
● Potency inconsistencies: Even within a single batch of 5-MeO-DMT, the potency can vary, leading to the risk of unintentionally consuming a much higher dose than intended (Petranker et al. 2022). Inconsistent potency and the presence of more potent adulterants increase the risk of accidental overdose (Petranker et al 2022; Hirschfeld et al. 2021; Palamar and Acosta 2020).
Sourcing from Unregulated Markets
● Unregulated sourcing and purity: 5-MeO-DMT is often sourced from unregulated markets, making the purity and dosage unpredictable (Bremler et al. 2023; Lancelotta and Davis 2020b) There is also the risk of adulteration or contamination with other substances (Bremler et al 2023) The sources of 5-MeO-DMT can include synthetic sources, toad venom, or plant extracts, which may have differing levels of potency and additional compounds that could cause harm(Lancelotta and Davis 2020b; Ortiz Bernal et al. 2022).
Adulteration and Contaminants
● Misrepresentation of substances: Substances sold as 5-MeO-DMT may not actually contain 5-MeO-DMT, leading to unexpected and potentially harmful effects (Hirschfeld et al 2021; Petranker et al 2022; Coyle, Presti, and Baggott, n d ; Bremler et al 2023; Calina, Carvalho, and Oana Docea 2021). There are several synthetic tryptamines that are similar to 5-MeO-DMT, such as 5-MeO-AMT, which have been sold as LSD and are known to be responsible for emergency cases(Calina, Carvalho, and Oana Docea 2021)
● Unknown toxicological profiles: Many novel psychoactive substances, including some that may be sold as or mixed with 5-MeO-DMT, have unknown toxicological profiles, increasing the risk of serious adverse effects (Hirschfeld et al 2021)
● Adulterants: Illicitly produced 5-MeO-DMT may be contaminated with other psychoactive substances, which can have their own specific effects and risks( Glynos et al 2023; Hirschfeld et al 2021; Petranker et al 2022; Strassman 1984) These adulterants can have a more dangerous safety profile than 5-MeO-DMT itself (Petranker et al. 2022). Contaminants and impurities can cause unexpected physiological and psychological effects, leading to greater anxiety, confusion, and other adverse reactions (Glynos et al. 2023; Hirschfeld et al. 2021).
● Manufacturing byproducts: Inadequate cleaning procedures of production equipment in illicit labs can lead to the presence of byproducts and impurities in the final product(Aakerøy et al. 2021).
● Unintended substances: Samples of 5-MeO-DMT may contain unintended substances due to cross-contamination during production, further increasing the risk of unpredictable effects (Hirschfeld et al. 2021; Petranker et al. 2022; Coyle, Presti, and Baggott, n.d.; Aakerøy et al 2021; Petranker et al 2022; Strassman 1984)
● Serotonin toxicity: Contamination with other serotonergic agents or the combination of 5-MeO-DMT with MAOIs can lead to serotonin toxicity (serotonin syndrome), a potentially life-threatening condition(Malcolm and Thomas 2022)
● "Research chemicals": Substances sold as "research chemicals" may be misrepresented and may also contain byproducts and contaminants (Coyle, Presti, and Baggott, n d )
● Long-term health problems: Chronic exposure to contaminants or repeated use of impure 5-MeO-DMT may lead to long-term health problems, although the specific risks are not yet well understood due to a lack of data(Hirschfeld et al 2021; Ghaznavi et al 2025).
Lack of Testing and Quality Control
● Lack of quality control: Unlike pharmaceutical products manufactured for clinical use, illicitly produced 5-MeO-DMT is not subject to quality control, making it difficult to assess its composition and safety (Glynos et al. 2023; Hirschfeld et al. 2021).
Contraindications
5-MeO-DMT-Specific Absolute Contraindications
These are conditions where 5-MeO-DMT use is completely inadvisable due to the high risk of significant harm:
1 Concurrent use of MAOIs: The combination of 5-MeO-DMT with MAOIs is a critical contraindication due to the high risk of serotonin syndrome, which can be fatal (Malcolm and Thomas 2022). This includes reversible MAOIs like moclobemide, as well as naturally occurring harmala alkaloids (e g harmine, harmaline, and tetrahydroharmine) found in ayahuasca and Syrian rue (Malcolm and Thomas 2022).
2 Personal or family history of psychotic disorders: Individuals with a personal or family history of schizophrenia, schizophreniform disorders, psychotic depression, or mania should avoid 5-MeO-DMT (Sabé et al 2024; White et al 2024) Use in these populations can increase risk of long-lasting psychotic reactions (Sabé et al. 2024) and other adverse effects.
5-MeO-DMT-Specific Relative Contraindications
These are conditions where 5-MeO-DMT use may still be possible but requires careful evaluation, monitoring, and risk-benefit assessment:
1. Cardiovascular issues: 5-MeO-DMT has a strong activation of G-protein binding, and the effects of that on individuals with cardiovascular conditions are not well understood (Malcolm and Thomas 2022). One study showed that DMT increased blood pressure and heart rate in a dose-dependent manner (James et al 2024)
2 Psychological vulnerabilities: Individuals with prior psychological vulnerabilities may be at higher risk of negative psychological responses such as anxiety or depression (Bremler et al 2023) One study found that anxiety symptoms arose or worsened in 87% of individuals who experienced negative responses to psychedelics (Bremler et al 2023).
3 Uncontrolled Settings: The unpredictable nature of 5-MeO-DMT makes it less safe in uncontrolled environments, where factors like dose, setting, and mindset cannot be managed effectively (Bremler et al. 2023).
4 Recreational use: Recreational use of 5-MeO-DMT lacks the safety measures of clinical or ceremonial settings, increasing risks from factors such as dosage uncertainty, adulterants, and lack of support (Gomez-Escolar et al 2024)
5 Mixing with other substances: Combining 5-MeO-DMT with other substances, especially other serotonergic substances, can increase the risk of adverse events, including serotonin toxicity (Malcolm and Thomas 2022; Barnett and Greer 2021)
Adverse Events
5-MeO-DMT carries risks of both acute and long-term adverse effects which vary in nature and intensity, and their occurrence can depend on factors such as dosage, individual predisposition, and context of use (Malcolm and Thomas 2022; Rucker et al 2024a; White et al 2024) Many studies indicate a favorable short term safety and tolerability profile for 5-MeO-DMT, with no SAEs reported in controlled clinical trials (Rucker et al. 2023; Hinkle et al. 2024; Kwaśny, Wilkowska, and Cubała 2024) Additionally, no adverse events have been documented that led to participants withdrawing from clinical trials (Kwaśny, Wilkowska, and Cubała 2024) Adverse events are more common in uncontrolled settings, such as recreational use, compared to clinical or ceremonial settings(White et al 2024; Rucker et al 2024b)
Acute Adverse Effects
The acute effects of 5-MeO-DMT are generally rapid in onset and short in duration, typically lasting between 45 to 90 minutes, though they can resolve completely in as little as 10 minutes in some cases (Rucker et al. 2023). These effects can be quite intense and may include a variety of physical, psychological, and behavioral changes (Rucker et al 2023; Dourron et al 2023), described below
One survey study of people who had used 5-MeO-DMT at least once reported that 37% experienced challenging psychological and somatic effects during their first time (Lancelotta and Davis 2020b). These effects included feelings of their heart beating, fear, body shaking, anxiety, feeling like they were dying, pressure on the chest, and panic (Lancelotta and Davis 2020b)
In another clinical study of intranasal 5-MeO-DMT, the most frequently reported treatment emergent adverse events were nasal discomfort, nausea, headache and vomiting (Rucker et al 2023). However, this same study also stated that "there were no serious adverse events, no observed effects on nasal mucosa and no clinically relevant changes in vital signs, ECG, telemetry, or laboratory safety tests" (Rucker et al. 2023).
Psychological Effects
1. Anxiety and fear: Some individuals may experience intense anxiety, fear, and overwhelming emotional experiences, particularly in the initial 10-15 minutes after dosing (Ramaekers, Reckweg, and Mason 2025b; Rucker et al 2024b; (Kwaśny, Wilkowska, and Cubała 2024). The intensity of the experience can be overwhelming (Lancelotta and Davis 2020b)
2. Psychological distress: While some experiences can be cathartic, 5-MeO-DMT can also cause psychological distress (Ramaekers, Reckweg, and Mason 2025b)
3 Confusional states: Some studies have reported "confusional states" as an adverse effect (Dourron et al 2023)
4. Hallucinations: Hallucinations have also been reported, though the specific nature of these experiences are not always detailed (Kwaśny, Wilkowska, and Cubała 2024; Dourron et al 2023)
5 Depressive symptoms: Depressive symptoms have also been reported in some acute cases (Kwaśny, Wilkowska, and Cubała 2024)
6 Ego dissolution and altered self experiences: 5-MeO-DMT is known for inducing a strong sense of ego dissolution, which can be both profound and disorienting (Falchi-Carvalho et al. 2024). Users may describe feeling detached from their body or having altered perceptions of self (Dourron et al 2023)
7 Intense mystical experiences: While these experiences are often seen as positive, the intensity can also be challenging for some users (Dourron et al 2023) Mystical experiences can include feelings of awe, amazement, loss of time and space, and difficulty putting the experience into words.
8. "White-out" experiences: Some users describe a "white-out" or loss of awareness (Dourron et al 2023) This effect can be disorienting and may contribute to a sense of loss of control (Dourron et al 2023)
Physiological Effects
1 Cardiovascular changes: 5-MeO-DMT can cause transient increases in blood pressure and heart rate (Ramaekers, Reckweg, and Mason 2025a; White et al 2024; Rucker et al. 2023; Kwaśny, Wilkowska, and Cubała 2024; Falchi-Carvalho et al. 2024).
2 Physical discomfort: Common acute adverse effects include nausea, headache, and vomiting (Ramaekers, Reckweg, and Mason 2025b; Rucker et al 2024b; White et al 2024). Nasal discomfort can also occur with intranasal administration (Rucker et al. 2024b) Muscle spasms and muscle discomfort have been reported as an acute effect of 5-MeO-DMT (Kwaśny, Wilkowska, and Cubała 2024).
3. Serotonin toxicity: The most dangerous acute effect is serotonin toxicity (serotonin syndrome), which can occur when 5-MeO-DMT is combined with MAOIs, including harmala alkaloids found in ayahuasca (Malcolm and Thomas 2022). This can be fatal.
4 Sensory disturbances: Users may experience sensory disturbances such as hyperacusis (increased sensitivity to sound) and blurred vision (Kwaśny, Wilkowska, and Cubała 2024)
5 Changes in body temperature: Users can experience feeling hot and related discomfort (Kwaśny, Wilkowska, and Cubała 2024).
6. Fatigue: Fatigue has been reported, often following the peak experience (Kwaśny, Wilkowska, and Cubała 2024)
7 Clumsiness: Some users report clumsiness as an acute effect (Kwaśny, Wilkowska, and Cubała 2024)
Behavioral Effects
1 Loss of behavioral control: 5-MeO-DMT can cause a loss of behavioral control, including unusual movements, twitching, and abnormal vocalizations (Dourron et al 2023)
2 Unpredictable behaviors: Some users may exhibit behaviors such as vomiting, screaming, or taking off their clothes (Dourron et al. 2023).
3. Potential for self-Injurious behavior: There are anecdotal reports of self-injurious behavior (Dourron et al 2023)
4 Involuntary movements: There are reports of involuntary bodily movements and seizure-like behaviors (Dourron et al 2023)
5 Lack of awareness of behavior: Users may lack awareness or memory of their behaviors during the acute effects (Dourron et al. 2023).
6. Highly sensual or hypersexual experiences: There have been reports of spontaneous orgasms (Dourron et al 2023)
Long-Term Adverse Effects
Psychological Effects
● Flashbacks/reactivations:
○ Definition: Reactivations are the spontaneous re-experiencing of drug effects after the acute effects of the substance have worn off (Dourron et al. 2023; Ortiz Bernal et al. 2022). They are similar to flashbacks but are reported more frequently with 5-MeO-DMT than with typical psychedelics (Dourron et al 2023)
○ Prevalence: Estimates of reactivation prevalence vary widely One study found 73% of users in a structured setting reported reactivations, compared to 27% in a general population sample (Dourron et al 2023; Ortiz Bernal et al 2022) Another study estimated that reactivations occur in 27% to 73% of naturalistic users (Dourron et al. 2023). In controlled research settings, a study found flashbacks in 25% of participants with treatment resistant depression and that they occurred in 25% of each dosing category (Dourron et al 2023) Vaporized or inhaled 5-MeO-DMT has a rapid onset and is more likely to lead to reactivations compared to intramuscular injection (Dourron et al 2023; Ortiz Bernal et al 2022).
○ Nature of reactivations: Reactivations are generally transient, but they can be intense (Ortiz Bernal et al 2022) They may involve re-experiencing aspects of the acute psychedelic state, including visual, emotional, and cognitive effects (Ortiz Bernal et al 2022) Some reports suggest that they may be more common at night while falling asleep (Ortiz Bernal et al 2022)
○ Valence of reactivations: Most reactivations are reported as either positive or neutral (Ortiz Bernal et al. 2022; Dourron et al. 2023). However, some individuals report negative reactivations, which can be distressing. For example, 4% of ceremonial users and 7% of general naturalistic users reported negatively valenced reactivations (Dourron et al 2023) In comparison, distressing flashbacks were only reported by 1 4% of people who participated in trials using LSD and psilocybin (Dourron et al. 2023).
○ Distress and impact: Although most reactivations are not negative, the small percentage that are negative can cause anxiety, panic, and other concerning emotional states, and can potentially require emergency crisis treatment (Ortiz Bernal et al 2022) There are some reports of people seeking psychological help and pharmacological intervention due to distressing reactivations (Dourron et al 2023).
○ Duration: Most reactivations tend to subside days or weeks after 5-MeO-DMT use (Ortiz Bernal et al. 2022). However, some anecdotal reports suggest that reactivations may continue for months, leading to anxiety and impaired sleep (Dourron et al 2023; Ortiz Bernal et al 2022) Unfortunately, the lack of long-term follow-up studies makes it impossible to determine the frequency, intensity, duration, and impairment associated with reactivations (Dourron et al. 2023).
● Hallucinogen Persisting Perception Disorder (HPPD):
○ Definition: While not explicitly linked to 5-MeO-DMT in the same way as other psychedelics like LSD, HPPD is still a concern (Ramaekers et al 2024) There
are two types of HPPD Type 1 is a short term, reversible, and benign course, also known as a "benign flashback," whereas Type 2 is more severe and long-term (Scala et al. 2024). The source material suggests that reactivations from 5-MeO-DMT may be similar to Type 1 HPPD because they tend to subside within weeks (Ortiz Bernal et al 2022)
○ Symptoms: Symptoms can include visual disturbances (e g , flashes, intensified colors, palinopsia), false perceptions of movement, recurrent synesthesia, dissociation, and depersonalization (Scala et al. 2024). However, no studies have documented HPPD stemming from 5-MeO-DMT specifically.
● Potential for Sensitization:
○ Repeated use: Some evidence suggests that 5-MeO-DMT can cause sensitization with repeated use, meaning that the effects of the drug become more pronounced (Dourron et al 2023) Sensitization is the opposite of tolerance, which is often seen with typical psychedelics (Dourron et al. 2023). One study in macaques showed behavioral sensitization after repeated administrations (Dourron et al 2023)
○ Dosing implications: Sensitization may explain why some studies using "individualizing dosing regimens" have reported higher levels of peak experiences (Dourron et al 2023) This may mean that some users become more sensitive to the drug after repeated use (Dourron et al. 2023).
● Other Potential Long-Term Effects:
○ Memory impairment: Although transient memory impairment is documented with psychedelics in general, there is no specific indication of long term memory impairment from 5-MeO-DMT (Kuypers and Ramaekers 2005)
○ Addiction potential: Data suggests that 5-MeO-DMT has a low addiction potential, similar to classic psychedelics (Kwaśny, Wilkowska, and Cubała 2024). The lifetime use of 5-MeO-DMT or bufotenine/toad secretions is rare (Kwaśny, Wilkowska, and Cubała 2024). However, it's important to note that while the risk of compulsive use is low, some people may repeatedly use the substance despite prior undesirable experiences (Dourron et al 2023)
○ Potential for negative emotional states: In some cases, negative emotional states have been reported to continue months after 5-MeO-DMT use. These could lead to clinically significant problems (Dourron et al. 2023; Ortiz Bernal et al. 2022).
○ Mental health iatrogenesis: A study focusing on negative psychological responses to psychedelics, including 5-MeO-DMT, found that 37 5% of participants had a psychiatric diagnosis that emerged after their psychedelic experience (Bremler et al 2023) Additionally, 87% reported that anxiety symptoms arose or worsened (Bremler et al. 2023). However, the prevalence of this effect is not fully understood (Bremler et al. 2023).
3. Harm Reduction and Safety Measures
6.1 Screening and Consent
Screening and informed consent are critical components of harm reduction strategies for psychedelic use, playing a crucial role in minimizing risks and ensuring participant safety (Bremler et al. 2023; Garcia-Romeu and Richards 2018; Palitsky et al., n.d.; Rosa et al. 2022). These processes help identify individuals who may be vulnerable to adverse events and ensure
that all participants are fully aware of potential benefits and harms before they engage in psychedelic experiences (Garcia-Romeu and Richards 2018; Palitsky et al., n.d.).
What Screening Does
1. Identify contraindications: Screening helps to identify individuals with contraindications for psychedelic use, including personal or family histories of psychosis, schizophrenia, or bipolar disorder (Marazziti et al. 2024; Honk et al. 2024; Henningfield et al. 2023). These conditions can increase the risk of adverse events, including the onset of psychosis, mania, or other severe psychiatric symptoms (Bremler et al 2023; Marazziti et al 2024; Henningfield et al. 2023). Exclusion of individuals with these conditions is standard practice in clinical trials to mitigate potential risks (Marazziti et al 2024) It is also common to exclude individuals with cardiovascular conditions due to the potential physiological effects of psychedelics (Aday et al. 2020).
2 Assess psychological vulnerabilities: Screening also evaluates potential psychological vulnerabilities, such as pre-existing mental health conditions, trauma, or a history of adverse reactions to drugs (Bremler et al. 2023). Those with a prior history of mental illness are more likely to report the occurrence or worsening of psychiatric symptoms post-psychedelic use (Bremler et al. 2023), with 87% of participants in one study experienced a worsening of anxiety symptoms in a long-term study (Bremler et al 2023). Individuals experiencing acute distress, suicidal ideation, or unstable mental health conditions may be more susceptible to challenging experiences and require additional support or alternative therapeutic approaches(Husain, Umer, and Mulsant 2022; Morton et al 2023)
3 Evaluate risk factors: Screening helps to identify risk factors that might increase the likelihood of adverse experiences (Bremler et al. 2023). These include unstable or complex environments during or surrounding the experience, previous unpleasant experiences with psychedelics, high or unknown drug quantities, young age, and trauma history (Bremler et al 2023) Tailoring the screening process to consider these individual factors can help identify specific vulnerabilities and guide informed decision-making (Morton et al. 2023; Bremler et al. 2023; Ghaznavi et al. 2025; Weiss et al. 2023).
4 Minimize adverse events: Screening and consent protocols are essential in reducing the risk of adverse events (Bremler et al 2023; Garcia-Romeu and Richards 2018; Palitsky et al., n.d.; Rosa et al. 2022). In clinical trials, these measures have been shown to be effective in minimizing severe outcomes, although there have been rare cases of treatment-emergent suicidality (Rosenblat et al 2023) Even though most adverse events in research settings are mild, the potential for severe and serious events remains, and therefore it’s critical to thoroughly implement screening and consent practices (Ehrenkranz et al. 2024).
5 Ensure participant safety: Careful screening is crucial for participant safety by excluding individuals who may be at a higher risk of experiencing negative psychological or physiological effects (Garcia-Romeu and Richards 2018; Rosa et al. 2022). This reduces the likelihood of serious outcomes, such as prolonged psychosis, severe anxiety, or suicidal ideation(Marazziti et al 2024; Rosenblat et al 2023) In addition,
screening can exclude those with concomitant drug use A study of psychedelic-related deaths found that 86% of deaths were accidental, and that 82% of deaths involved polysubstance use, indicating that screening and education for users may reduce risky combinations of drugs (Kopra et al. 2025).
6 Determine eligibility: Screening is essential for determining if a potential participant is a suitable candidate for psychedelic-assisted therapy (Rosa et al 2022) This process ensures that only individuals who are likely to benefit from the treatment, and whose risk of adverse effects are minimized, are included
7 Build trust: A transparent consent process can build trust between participants and practitioners by showing a commitment to safety and ethical practice (Garcia-Romeu and Richards 2018; Rajwani 2022)
8 Adhere to ethical practice standards: Screening and informed consent adhere to principles of medical ethics by ensuring patient safety and promoting patient autonomy and choice (Bremler et al 2023; Rajwani 2022)
9. Improve treatment outcomes: By identifying and addressing potential risks, screening and consent contribute to more positive therapeutic outcomes, as well as a better understanding of the risk/benefit profile of psychedelic-assisted therapies (Garcia-Romeu and Richards 2018; Palitsky et al., n.d.; Ehrenkranz et al. 2024).
10 Ensure legal compliance: These measures comply with regulatory requirements for clinical trials and provide a level of protection for both patients and the clinicians and researchers involved in the process. (McGuire et al., 2024)
The Role of Informed Consent
1. Provide comprehensive information: Informed consent requires transparently outlining the potential psychological, physical, and spiritual effects of psychedelics and any alternative treatment options available (Palitsky et al., n.d.; Rajwani 2022. Individuals should understand both the potential therapeutic benefits and the possibility of challenging experiences, including anxiety, fear, temporary distress, and the possibility of re-experiencing traumatic memories (Davis et al. 2022; Kočárová, Horáček, and Carhart-Harris 2021; “How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024; Devenot et al 2022; Dupuis 2021; Garcia-Romeu and Richards 2018; Rajwani 2022; Rossi et al. 2022) as well as the likely time course of effects and how to manage them (Henningfield et al 2023)
2. Explain the therapeutic process and integration: Participants should understand the therapeutic model, the role of therapists or guides, and the importance of integration practices. This includes discussing the process of making sense of the experience, integrating insights into daily life, and addressing any challenges that may arise (“How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024; Ashraf 2024; Dupuis and Veissière 2022; Gezon 2024; Kishon et al 2024; Kočárová, Horáček, and Carhart-Harris 2021; Pilecki et al 2021)
3. Discuss set and setting: Participants should be informed about strategies for creating a safe, supportive, and conducive environment for the session (Aday, Bloesch, and Davoli
2020; Morton et al 2023; Bremler et al 2023; Ghaznavi et al 2025; Garel et al 2023; Haden, Emerson, and Tupper 2016; Haijen et al. 2018; Hartogsohn 2017; Palmer and Maynard 2022; 2022; Schlag et al 2022)
4. Address unique effects: Psychedelic experiences are unique, and traditional consent procedures may not adequately cover all the potential implications (Rajwani 2022) It is important to disclose the possibility of significant shifts in values and personality, as well as the potential for changes in judgment and beliefs, all of which should be carefully considered prior to engaging in a psychedelic experience (Rajwani 2022)
5 Ensure voluntariness: Informed consent ensures that participation is voluntary and free from coercion (Bremler et al. 2023; Rajwani 2022). Participants should be given ample opportunity to ask questions, express concerns, and make their decisions without pressure from clinicians or researchers (Rajwani 2022)
6. Respect autonomy: Informed consent respects the autonomy of the individual by empowering them to make informed decisions about their own healthcare (Rajwani 2022). This involves acknowledging their right to choose whether or not to participate in the therapy, and to withdraw at any time (Rajwani 2022)
7 Enhance consent: An "enhanced" informed consent process that goes beyond typical informed consent procedures for other psychiatric interventions may be required for psychedelic therapies (Rajwani 2022) This enhanced process includes in-depth discussions with patients regarding the unique effects of psychedelics, including the possibility of significant shifts in values and personality, and mental health risks like transient anxiety, challenging experiences, trauma re-exposure, and added risks for those with psychotic disorders or a family history of such disorders (Rajwani 2022)
8. Explain ongoing consent: Participants should be informed that they have the right to withdraw consent at any point, even during the session Providing a safe and supportive environment where individuals feel empowered to voice their needs and limits is essential (Lacroix et al 2024; O’Donnell, Grigsby, and Grob 2025)
Specific Screening and Consent Measures
1 Standardized questionnaires: Use standardized questionnaires to assess psychiatric history, substance use, and other risk factors Validated tools for assessing side effects, such as the Swiss Psychedelic Side Effects Inventory (SPSI) can be used to collect systematic data on side effects (Calder et al 2024) which helps improve the quality of treatment decisions (Calder et al 2024)
2. Clinical interviews: Conduct thorough clinical interviews with trained professionals to gather detailed information about medical and psychiatric history and assess current mental state (Garcia-Romeu and Richards 2018; Palitsky et al., n.d.).
3 Medical evaluations: Perform medical evaluations to identify physical health conditions that may increase risks associated with psychedelic use (Aday et al 2020)
4. Comprehensive disclosure: Provide participants with a detailed description of the study procedures, potential risks and benefits, and any alternative treatment options available It is especially important to disclose the potential for challenging experiences (Garcia-Romeu and Richards 2018; Rossi et al. 2022).
5 Opportunities for questions: Encourage participants to ask questions and address any concerns before making a decision (Garcia-Romeu and Richards 2018; Rajwani 2022).
6 Documentation: Obtain written informed consent from all participants, documenting their understanding of the process and their voluntary agreement to participate (Palitsky et al , n d ; Rajwani 2022)
7 Preparation meetings: Many models of psychedelic therapy include multiple preparation meetings with therapists before the drug administration sessions (Garcia-Romeu and Richards 2018) These meetings help build rapport, review the patient’s life history, discuss potential drug effects, and address any concerns (Garcia-Romeu and Richards 2018).
8 Harm reduction strategies: Harm reduction strategies, such as starting with a small test dose, using psychedelics in a safe and familiar environment, and having a trusted support person present, are part of an overall safety framework (Baxter et al. 2024).
9 Peer support networks: Utilizing peer support networks to disseminate information about harm reduction practices and safe psychedelic use can improve outcomes by incorporating lived experiences (Baxter et al 2024)
10 Transparent reporting: Studies have called for the systematic assessment of adverse events, recommending specific, targeted questions in addition to open-ended questions, and including both clinician- and patient-reported outcomes, as well as reports from those close to the patient (Palitsky et al , n d ; Cheung et al 2024) This improves the quality of data collected (Cheung et al. 2024).
11 Continuous monitoring: Monitoring during and after the psychedelic experience is essential (Ledwos et al 2022) Continuous support helps to manage any distress or adverse reactions and ensure the individual has adequate integration following a session (Garcia-Romeu and Richards 2018; Rossi et al 2022)
Examples of Effective Screening and Consent Practices
● Multidisciplinary Association for Psychedelic Studies (MAPS): MAPS has developed comprehensive guidelines for psychedelic therapy training and clinical trials, emphasizing thorough screening, informed consent, and ethical considerations (Glynos et al 2023; Pilecki et al 2021)
● Johns Hopkins Center for Psychedelic and Consciousness Research: The center has rigorous protocols for psilocybin research, including extensive screening, preparation sessions, and ongoing support for participants (Pilecki et al 2021)
6.2 Setting
"Setting" refers to the physical, social, and cultural environment in which a psychedelic experience occurs (Bender and Hellerstein 2022; Gandy et al. 2020; Hartogsohn 2022). It plays a crucial role in shaping the outcome, influencing the potential for both benefits and harms (Campo and Yali 2024; Robin L Carhart-Harris et al. 2018; Haijen et al. 2018; Hooyer, Applbaum, and Kasza 2023; Johnstad 2021; Garcia-Romeu and Richards 2018; Davis et al , n d ) This understanding has been a key aspect of psychedelic research since the 1960s, with the recognition that psychedelics can amplify
the effects of contextual influences (Garel et al. 2023; Haden, Emerson, and Tupper 2016; Hartogsohn 2017)
For a detailed discussion of the risks posed by setting-related factors, see section 5.4 above. Presented below are some specific measures and techniques for reducing these risks and their harms.
Specific Measures and Techniques Related to Setting
1. Physical Environment:
○ Create comfortable and relaxing spaces: The environment for a psychedelic experience should be physically comfortable and aesthetically pleasing, minimizing potential distractions or stressors (Golden et al 2022; Garcia-Romeu and Richards 2018) Therapeutic settings often involve a warm, dedicated room with pleasing artwork and a comfortable place to recline, such as a sofa (Golden et al. 2022; Holze et al. 2022). Natural settings have also been found to be beneficial (Walther and van Schie 2024). Regardless of the physical setting selected, participants should feel secure and have a sense of privacy (Golden et al 2022; Holze et al 2022)
○ Ensure safety: The setting should be free from hazards, and it should be ensured that participants will not operate machinery or vehicles while under the influence (Haden, Emerson, and Tupper 2016)
○ Minimize clinical atmosphere: A clinical atmosphere, such as a PET scanning environment, can increase anxiety during psychedelic administration. An aesthetically pleasing and non-clinical environment should be prioritized to mitigate this risk (Garcia-Romeu and Richards 2018)
○ Provide music and sensory stimulation: The use of curated music playlists and eyeshades can help to guide the psychedelic experience and minimize distractions (Golden et al 2022) Music may provide a structure through which the drug user navigates the experience (Golden et al. 2022).
2. Social Environment:
○ Establish clear guidelines and boundaries: Participants should be informed about the expectations for behavior, communication, and interactions during the session (Haden, Emerson, and Tupper 2016) Setting clear boundaries can help create a sense of structure and predictability, minimizing potential anxiety or confusion (Haden, Emerson, and Tupper 2016).
○ Provide experienced facilitators/social support: The presence of trained therapists, guides, or "trip sitters" who can provide emotional support, reassurance, and guidance is crucial, especially for those new to psychedelics or working through challenging material (Golden et al 2022; Gashi, Sandberg, and Pedersen 2021; Haden, Emerson, and Tupper 2016; Kopra et al 2022; Pilecki et al. 2021; Davis et al., n.d.; Baxter et al. 2024; Garcia-Romeu and Richards 2018). Facilitators should be knowledgeable about the medical and psychological markers of potential adverse reactions to the drug (“Developing Guidelines and
Competencies for the Training of Psychedelic Therapists,” n d ) 79 6% of respondents in one study reported taking LSD with a close friend, group of friends, partner or lover (Baxter et al. 2024).
○ Build a therapeutic alliance: This involves establishing rapport and trust during preparation meetings prior to drug administration (Davis et al , n d ; Garcia-Romeu and Richards 2018) Rapport with session facilitators has been shown to mediate positive acute experiences and long-term outcomes (Davis et al., n.d.), including greater emotional breakthrough and mystical-type experiences, leading to improved outcomes (Davis et al., n.d.). The setting should offer privacy to the individual but also include the presence of two therapists or guides with whom the participant has already built rapport (Golden et al 2022)
3 Cultural Context:
○ Cultural sensitivity: It is important to consider the cultural context of participants and tailor the setting to meet their needs (Jones and Nock 2022; Gezon 2024; Golden et al 2022) This can involve incorporating cultural practices, symbols, or music that resonate with the individual's background, fostering a sense of familiarity and safety(Robin L Carhart-Harris et al 2018; Aday et al 2021; Dupuis and Veissière 2022; Hartogsohn 2021) Current treatment settings that are mostly designed, assessed, and administered by people of European descent may not promote positive outcomes for racial and ethnic minorities (Jones and Nock 2022).
○ Rituals and ceremonies: In some traditions, elements such as ritual songs, whistles, smoke blowing, and sucking are part of the setting (Golden et al 2022) These practices can provide a structure and framework for the psychedelic experience
○ Group vs. individual settings: Group settings may be ideal for certain individuals, populations, or therapeutic outcomes. In some instances, group therapy has been suggested to be potentially beneficial for participants undergoing psychedelic therapy by supporting feelings of unity and understanding (Golden et al 2022)
○ Individualize the approach: Recognize that individual preferences can shape the effects of music and environment on psychedelic experiences, and methods to customize settings may yield optimal results (Golden et al. 2022; Okano et al. 2022).
Examples of Effective Implementation
1 Clinical trials: Contemporary clinical trials often utilize a standardized setting for psychedelic therapy, typically involving a comfortable room, trained therapists, and carefully curated music playlists (Golden et al. 2022; Gandy et al. 2020). This controlled environment helps minimize distractions and potential risks (Golden et al 2022; Pilecki et al 2021)
2
Retreat centers: Psychedelic retreats often emphasize natural or aesthetically pleasing settings, as well as social and ceremonial support (Neitzke-Spruill et al. 2024). These settings are designed to promote relaxation, openness, and a sense of connection. One study found 56% of respondents took psychedelics in a retreat or other therapeutic setting (Gukasyan and Nayak 2022)
3 Harm reduction initiatives: Harm reduction efforts include educating individuals to choose safe, familiar settings for psychedelic use and to avoid using in new or unfamiliar environments (Lea et al. 2020).
4. Microdosing practices: Individuals who microdose often report specific harm reduction practices related to setting, such as only microdosing at home or in quiet, familiar settings (Lea et al 2020)
5 Traditional indigenous practices: Many indigenous cultures have developed sophisticated rituals and ceremonies involving psychedelics These practices often involve meticulous preparation, specific settings, and experienced guides who provide guidance and support (Robin L Carhart-Harris et al. 2018; Aday et al. 2021; Dupuis and Veissière 2022; Hartogsohn 2021; Golden et al 2022)
6.3 Dose and Substance Preparation
Specific Measures for Dose and Substance Preparation to Reduce Risk and Harm
● Dose Selection:
○ Start low and go slow: In non-clinical settings, starting with a low dose, especially for first-time users or when trying a new substance, is advised (Bornemann 2020). This approach allows individuals to gauge their sensitivity and tolerance to the psychedelic before increasing the dose, thereby decreasing the likelihood of a negative experience (Baxter et al 2024; Basedow et al 2024; Izmi, Carhart-Harris, and Kettner 2024; Palmer and Maynard 2022; 2022; Villiger 2024) For example, a study exploring psilocybin dosing found that a lower initial dose (10mg) resulted in similar adverse events as a standard dose (25mg), while a very low dose (1mg) showed no serious adverse events (Villiger 2024). In clinical settings, clinicians may start with microdoses and gradually increase the dose to optimize the therapeutic response and manage patient tolerance (Scala et al 2024) Therapeutic settings should consider each patient's unique needs and sensitivities when determining an appropriate dose (Scala et al 2024)
○ Weight-based dosing: In clinical trials, doses of psilocybin are often calculated on a per-kilogram basis to account for variations in body weight (Bender and Hellerstein 2022). For example, one study found correlations between the dose of psilocybin and the probability of having a “complete” mystical-type experience, with 0, 5 6, 11 1, 44 4, and 55 6% experiencing such at 0, 0 07, 0 14, 0 29, and 0 43 mg/kg doses, respectively (Bender and Hellerstein 2022)
○
Microdosing: Microdosing involves taking sub-perceptual doses of a psychedelic, typically one-tenth to one-twentieth of a normal dose, with the goal of enhancing well-being or cognitive function without inducing a full psychedelic experience (Bornemann 2020; Lea et al 2020; Anderson et al 2019) This approach is aimed at minimizing the risks associated with full-dose use while exploring the potential benefits (Bornemann 2020) The majority of microdosers report using LSD (65%) and/or psilocybin (28%) (Anderson et al 2019) Microdosers often adhere to consistent schedules, typically one day on followed by two days off. (Rosenbaum et al, 2020)
○ Harm reduction: Microdosers often employ harm reduction strategies such as avoiding alcohol and caffeine on microdosing days (Lea et al 2020)
○ Dose adjustment: Some users adjust their dose based on their previous experiences and desired effects, using an iterative approach (Lea et al 2020)
○ Defined dose limits: Setting a predetermined limit on the amount of psychedelic substance to consume and intentionally spacing out doses within a session are both recognized harm reduction measures (Piercey et al 2024)
○ Plasma level monitoring: Measuring plasma psilocin levels, similar to what is done with conventional antidepressants, can help optimize the dose of psilocybin (Scala et al 2024)
● Substance Preparation and Testing:
○ Purity and and dose measurement: When dealing with substances like LSD, which often come in blotter form, precise volumetric dosing is crucial. This involves dissolving a known quantity of LSD in a specific volume of liquid to ensure consistent doses (Miller et al 2024; 2024) Advise against cutting LSD blotters for dose preparation, as this can lead to inconsistent dosing (Miller et al 2024).
○ Test doses: Test substances before use to verify their composition and identify any potentially harmful adulterants, thus preventing accidental ingestion of dangerous substances sold as psychedelics (Palmer and Maynard 2022; Miller et al 2024; 2024) Taking a small test dose of a new substance can help assess its purity and potency before consuming a larger amount (Baxter et al 2024) Less than a third (31.3%) of first-time LSD users reported taking a test dose, indicating a potential area for improving harm reduction practices (Baxter et al. 2024).
○ Reagent test kits: Drug testing reagents like Ehrlich's reagent are affordable tools that can confirm the presence of the intended drug and rule out the presence of harmful adulterants (Miller et al 2024; Lea et al 2020)
○ Trusted sources: Obtaining substances from a trusted source can also reduce the risk of inadvertently consuming adulterated substances (Lancelotta and Davis 2020; Palmer and Maynard 2022; Miller et al. 2024).
● Routes of Administration:
○ Oral administration: Most clinical administration of psychedelics is oral (Garcia-Romeu and Richards 2018) This route is convenient for clinical use
○ Alternative routes: Alternative routes such as intramuscular or intravenous injection can affect the time of onset and the intensity of the drug effect (Garcia-Romeu and Richards 2018).
6.4 Supervision and Facilitation
Good supervision and facilitation during psychedelic experiences are vital for minimizing potential risks and enhancing positive outcomes, whether in therapeutic, research, or recreational contexts (R L Carhart-Harris et al 2018; Kishon et al 2024; Nichols and Barker 2016; Garcia-Romeu and Richards 2018; O’Donnell, Grigsby, and Grob 2025). They provide support and guidance before, during, and after the experience to address emotional and psychological needs, manage potential adverse effects, and assist with integration
The Role of Supervision and Facilitation
1 Creating a safe environment: The presence of trained professionals or experienced guides is particularly crucial with psychedelic substance use as it can induce altered states of consciousness, increasing vulnerability to psychological distress or impaired judgment (Husain, Umer, and Mulsant 2022). Supervision and facilitation help create a safe and supportive environment that minimizes anxiety, fear, and other negative emotions that can arise during a psychedelic experience (Garcia-Romeu and Richards 2018; Wilson-Poe et al 2024) Overall, practitioners should adopt a harm reduction approach that prioritizes client safety and well-being (“How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024; Barber and Dike 2023).
2 Managing challenging experiences: A skilled facilitator can help individuals navigate challenging experiences, such as anxiety, dysphoria, or paranoia, by offering support, guidance, and reassurance The ability to effectively manage these experiences can prevent them from escalating into more severe adverse events (Rossi et al. 2022; Henningfield et al. 2023).
3. Promoting integration: Facilitation plays a key role in helping individuals integrate their psychedelic experiences, especially in therapeutic contexts (Garcia-Romeu and Richards 2018; Aday et al 2024)
4 Ensuring ethical practice: Good supervision is essential for maintaining ethical boundaries and preventing harm. It ensures that facilitators adhere to professional standards and avoid inappropriate or exploitative behavior (Rosa et al. 2022).
5. Enhancing therapeutic outcomes: In therapeutic settings, the quality of facilitation directly influences therapeutic outcomes A strong therapeutic alliance between the facilitator and the participant is associated with better results (Wilson-Poe et al 2024)
6
Reducing the risk of adverse events: Proper supervision can also reduce risks of negative outcomes. For example, one study of early psychedelic research found that "prolonged reactions" occurred at a rate of 1.8 per 1000 patients. The same study found that suicide attempts and completed suicides occurred at a rate of 1 2 and 0 4 per 1000 patients, respectively However, it was noted that "the causal link between hallucinogen exposure and suicide or suicide attempt was only clear for a portion of these cases in patients," suggesting proper supervision and facilitation could help reduce these numbers further (Johnson, Richards, and Griffiths 2008).
Specific Measures and Techniques
1 Preparation Sessions:
○ Screening: Participants should be screened to determine individual suitability for psychedelic experiences and to identify those at higher risk (Garcia-Romeu and Richards 2018; Rosenblat et al. 2023; “Developing Guidelines and Competencies for the Training of Psychedelic Therapists,” n.d.). This involves reviewing the individual’s prescription medication history and ensuring contraindicated medications are stopped before a session is essential for safety (Davis et al , n d ) as well as identifying contraindications such as pre-existing mental health conditions, cardiovascular conditions, personal or family history of schizophrenia, psychotic disorder, or bipolar disorder, and potential drug interactions (Breeksema et al. 2022; Haden, Emerson, and Tupper 2016; Aday et al 2020; “Developing Guidelines and Competencies for the Training of Psychedelic Therapists,” n d ; Henningfield et al 2023)
○ Preparation: Participants should receive comprehensive information about the potential effects, both positive and challenging, of the substance being administered (Kirlić et al 2025; Garcia-Romeu and Richards 2018) This prepares them for the experience and equips them with coping strategies to manage difficult experiences (Robin L Carhart-Harris et al. 2018; Haijen et al. 2018) Psychological preparation also involves establishing therapeutic intentions, addressing potential emotional triggers, and fostering a trusting relationship with therapists or facilitators (R L Carhart-Harris et al 2018; Morton et al 2023; Garel et al 2023) Participants should provide informed consent after receiving detailed information about the process, risks, and benefits as part of ethical practice (Hinkle et al 2024; Palitsky et al , n d )
○ Life review: Preparation sessions typically include a review of the participant's life history, major life events, relationships, and world view. This helps the facilitator build rapport and understand the individual’s background and current context (Garcia-Romeu and Richards 2018).
○ Addressing fears: Exploring and addressing participants’ fears, concerns, and questions about the session is essential for building trust and confidence (Garcia-Romeu and Richards 2018)
2. Facilitator Qualities:
○ Empathy and rapport: Empathy and rapport are important traits in facilitators as they create trust and enhance the therapeutic alliance (Wilson-Poe et al. 2024). Facilitators should be able to create a non-hierarchical relationship that can empower clients and ensure their perspectives are valued (Zeller, n d )
○ Experiential knowledge: Some sources suggest that personal experience with psychedelics may enhance facilitators’ ability to connect with and support individuals during psychedelic experiences (Wilson-Poe et al , 2024)
○ Self-care: Facilitators who engage in self-care through personal therapy or other methods have been shown to improve their reliability and empathy(Wilson-Poe et al 2024)
○ Training: All facilitators should receive standardized training that covers ethical practices, risk management, and techniques for supporting individuals through challenging experiences (Cheung et al , n d ; Aday et al 2024; “Developing Guidelines and Competencies for the Training of Psychedelic Therapists,” n.d.).
○ Ongoing supervision: Facilitators should also receive ongoing supervision from experienced mental health professionals (Cheung et al , n d ) Regular supervision and peer review can help prevent ethical lapses and boundary violations (“Developing Guidelines and Competencies for the Training of Psychedelic Therapists,” n d )
○ Ability to adhere to ethical guidelines: Clear ethical guidelines and professional standards are essential for all practitioners in this field (“Developing Guidelines and Competencies for the Training of Psychedelic Therapists,” n.d.). Maintaining clear therapeutic boundaries is crucial to preventing exploitation or inappropriate relationships (Rosa et al 2022)
3 Roles During the Session:
○ Continuous monitoring: Facilitators should prioritize physical and emotional safety above all else, ensuring all necessary precautions are taken to minimize potential harms (Palitsky et al., n.d.; Kishon et al. 2024; Nichols and Barker 2016) This should be done through continuous monitoring throughout the psychedelic experience, allowing for any distress or challenges to be addressed and preventing the escalation of negative effects (Henningfield et al 2023) Their role is to manage challenging experiences, offer reassurance, and intervene if necessary (Haden, Emerson, and Tupper 2016).
○ Non-directive support: Facilitators should provide non-directive support and allow individuals to explore their experiences without interference (Henningfield et al 2023)
○ Reassurance and grounding: Providing verbal reassurance and employing grounding techniques can help individuals manage difficult emotions and experiences (Henningfield et al. 2023). For instance, therapists can remind distressed individuals that their altered state is temporary and caused by the substance (Engel, Thal, and Bright 2022a)
4 Integration Sessions:
○ Meaning making: It is important to devote adequate time and resources to the integration process (Palitsky et al., n.d.). Integration focuses on post-session support through therapy or other supportive practices (Kishon et al. 2024) that help individuals process the experience, extract meaning, and integrate insights into their lives (Garcia-Romeu and Richards 2018; Engel, Thal, and Bright 2022a; Pilecki et al 2021) This often involves therapy sessions where participants share their experiences, explore personal insights, and address unresolved issues (Kishon et al. 2024; Pilecki et al. 2021).
○ Behavioral change: Support in making behavioral changes based on insights is critical for long-term growth (Garcia-Romeu and Richards 2018)
○ Continued support: Ongoing support helps ensure that the therapeutic effects last over time (Freitas et al 2024)
Examples of Effective Implementation
1. Clinical trials: Rigorous protocols are employed in clinical trials for psychedelic-assisted therapy, encompassing participant selection, preparation, dosing, session monitoring, and integration(Kishon et al 2024) Clinical trials typically implement rigorous protocols for facilitator training and supervision (Garcia-Romeu and Richards 2018) The controlled environment and trained medical personnel significantly minimize risk and increase the likelihood of positive outcomes (Davis et al. 2022; Pilecki et al. 2021).
2. Retreat centers: Many retreat centers that offer psychedelic experiences incorporate elements of preparation, integration, and ongoing support into their programs (Golden et al 2022)
3 Peer support networks: In non-clinical settings, peer support networks can be a valuable resource for individuals seeking guidance and support around their psychedelic use (Baxter et al. 2024). These networks often emphasize harm reduction practices, responsible use, and integration strategies, allowing individuals to share experiences, process insights, and integrate their psychedelic experiences into daily life (Gezon 2024) Facilitators can guide discussions, offer support, and foster a safe environment (Gezon 2024; Barber, Gardner, and Carter 2024)
4. Online forums: Online communities provide platforms for sharing information and experiences, including tips on safe use, challenging experience management, and integration. However, these forums should be viewed as a supplement, and not a substitute, for guidance from trained and supervised facilitators (Cheung et al , n d )
● Harm reduction organizations: Organizations like the Zendo Project offer harm reduction services at events where psychedelic use is prevalent (Ruane 2015). They create a safe environment for those undergoing challenging experiences, offering support, guidance, and de-escalation strategies (Golden et al 2022)
6.5 Preparation
Thorough preparation is essential to mitigate risks and enhance positive outcomes associated with psychedelic use. This includes both psychological preparation, focusing on mindset and intentions, and practical preparation, addressing factors like dosage and setting (Ashraf 2024; Bălăeţ 2022a; R. L. Carhart-Harris et al. 2018; Edelsohn and Sisti 2023; Garel et al. 2023; Gorman et al 2021; McAlpine et al 2024; 2024; Palmer and Maynard 2022; Pilecki et al 2021; Shaw et al 2023; White et al 2024; Garcia-Romeu and Richards 2018; Davis et al , n d )
Thorough preparation can significantly reduce the likelihood of challenging experiences and enhance the potential for positive outcomes (Davis et al , n d ; Zeller, n d )
The Role of Preparation in Reducing Risks and Harms
1. Managing expectations: Preparation helps individuals develop realistic expectations about the psychedelic experience (Garcia-Romeu and Richards 2018; Davis et al , n d ) This reduces the likelihood of feeling overwhelmed by the intensity of the experience, and helps prevent feelings of frustration or disappointment if therapeutic effects are not immediate (Freitas et al 2024)
2. Reducing anxiety and fear: By providing education and addressing concerns, preparation can reduce anxiety and fear associated with the psychedelic experience (Garcia-Romeu and Richards 2018; Rossi et al 2022) A calm and grounded state of mind before the session is associated with fewer adverse outcomes (Davis et al , n d ; Russ et al 2019)
3 Optimizing psychological state: Preparation helps ensure that individuals enter the experience with a positive mindset, which is crucial for minimizing adverse outcomes. Those with lower average moods prior to taking LSD have been shown to be more likely to have negative experiences (Baxter et al 2024)
4 Setting clear intentions: Establishing clear intentions for the psychedelic experience can guide the session and increase the likelihood of positive therapeutic outcomes Participants who are confident in their reasons for the session, and are able to "trust, let go, and be open" tend to report fewer adverse outcomes (Davis et al., n.d.).
5. Enhancing safety: Preparation includes practical measures that improve the safety of the experience, such as choosing a secure setting, planning for the session, and having a “trip-sitter” (Baxter et al 2024)
6 Facilitating integration: Preparation lays the groundwork for post-session integration, enabling individuals to process their experiences and apply insights to their daily lives (Robinson et al. 2024; Garcia-Romeu and Richards 2018).
7. Addressing potential challenges: Preparation allows individuals to understand that challenging experiences, though difficult, can be a part of the psychedelic process and provides tools for managing such experiences (Garcia-Romeu and Richards 2018)
Specific Preparation Measures and Techniques
1. Multiple sessions: Preparation should involve multiple sessions to build rapport, address all concerns, and ensure comprehensive understanding (Garcia-Romeu and Richards 2018)
2
Screening: As discussed above in section 6 4, screening assesses individuals’ suitability for psychedelic use, identifying contraindications like pre-existing mental health conditions (e.g., bipolar disorder or psychosis), potential drug interactions, and other risk factors (Aday, Bloesch, and Davoli 2020; Davis et al 2022; Ghaznavi et al 2025; Haden, Emerson, and Tupper 2016; 2016; Kočárová, Horáček, and Carhart-Harris 2021; Lacroix et al 2024; Morton et al 2023; Peterson et al 2023; Rosenbaum et al 2024) Preparation includes implementing thorough screening procedures to prevent participation of individuals with conditions that may be exacerbated by psychedelics (Davis et al. 2022).
3 Education about psychedelics: Preparation should provide comprehensive information about potential psychedelic effects, including both positive and challenging aspects, to help individuals cultivate realistic expectations and develop coping mechanisms for difficult experiences (R L Carhart-Harris et al 2018; McAlpine et al 2024; Pilecki et al 2021; White et al. 2024; Gorman et al. 2021; McAlpine et al. 2024; Neitzke-Spruill et al. 2024; Pilecki et al. 2021; Smith and Sisti 2021; Weiss et al. 2023; Zeller, n.d.; “How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024; Garcia-Romeu and Richards 2018; Rossi et al 2022). This should include detailed information about the effects of the specific psychedelic, including its onset, duration, and potential psychological and physical effects (Garcia-Romeu and Richards 2018); appropriate dosing and the effects of different doses (Piercey et al. 2024); and harm reduction practices, such as test-dosing and the use of a “trip-sitter” (Baxter et al. 2024).
4 Mental and emotional preparation:
○ Life review: Reviewing life history, major events, and relationships can provide a helpful context for understanding the psychedelic experience (Garcia-Romeu and Richards 2018).
○ Addressing fears and anxieties: Openly discussing and addressing fears, concerns, and questions about the session can reduce anxiety and enhance the individual's sense of preparedness (Garcia-Romeu and Richards 2018)
○ Setting intentions: Preparation should include helping individuals define clear intentions and goals for their psychedelic experience, focusing on desired outcomes like personal growth, healing, or spiritual exploration.(R. L. Carhart-Harris et al. 2018; Garel et al. 2023; Gorman et al. 2021; Haijen et al. 2018; 2018; Palmer and Maynard 2022; Davis et al., n.d.). Motivations for psychedelic use should align with potential benefits and responsible use (Pilecki et al 2021; Palmer and Maynard 2022)
○ Cultivating acceptance: Encouraging attitudes of acceptance and surrender can be predictive of a more positive, less challenging, experience (Davis et al., n.d.).
5. Logistical and Environmental Preparation:
○ Safe setting: Planning the setting for the experience is crucial Create a safe, comfortable, and supportive environment for the psychedelic experience,
minimizing external distractions and maximizing a sense of security (Bălăeţ 2022a; Pilecki et al. 2021; Shaw et al. 2023; Davis et al. 2022; Ghaznavi et al. 2025; Haden, Emerson, and Tupper 2016; Morton et al. 2023; Neitzke-Spruill et al 2024; Gorman et al 2021; Haijen et al 2018; 2018; Palmer and Maynard 2022; Anderson et al 2019; 2019; Devenot et al 2022; Haden, Emerson, and Tupper 2016; Kočárová, Horáček, and Carhart-Harris 2021; McAlpine et al 2024; Palmer and Maynard 2022; Schlag et al 2022; Davis et al , n d ; Bremler et al 2023).
○ Physical needs: Preparation should include ensuring physical needs are taken care of including providing water, easy access to the restroom, and ensuring a comfortable place to sit or lie down (Robinson et al 2024)
6 Preparation for Challenging Experiences:
○ Accepting difficulties: Preparation should include acknowledging the possibility of challenging experiences and normalizing that such experiences can be part of the process (Garcia-Romeu and Richards 2018; Rossi et al 2022)
○ Coping strategies: Participants should be provided with techniques for managing difficult emotions, such as deep breathing, self-talk, and distraction (Robinson et al. 2024; Kirlić et al. 2025).
○ Knowing when to ask for help: Ensure users know they can rely on their facilitators and that these facilitators are prepared to support them if needed (Garcia-Romeu and Richards 2018; Baxter et al 2024)
○ Explore potential emotional triggers: Preparation should include providing tools for navigating difficult emotions that may surface during the psychedelic experience (Gorman et al 2021; Kirlić et al 2025)
Examples of Effective Implementation
1. Clinical trials: Clinical trials often involve multiple preparation sessions before the psychedelic experience These sessions usually include life reviews, education about the drug, discussion of potential effects, setting intentions and building a therapeutic alliance (R L Carhart-Harris et al 2018; McAlpine et al 2024; Pilecki et al 2021; C Robinson et al 2024; Morton et al 2023; Garcia-Romeu and Richards 2018)
2. Psychedelic retreats: Many retreat centers emphasize preparation as a critical component of the experience. These programs typically include informational sessions, opportunities for setting intentions, and measures to create a safe and supportive setting (Baxter et al 2024; McAlpine et al 2024)
3 Harm reduction organizations: Groups like the Zendo Project, which provide support at events, often emphasize preparation through educational materials and workshops on safe psychedelic use practices (Engel, Thal, and Bright 2022a; Hartogsohn 2017; Pilecki et al. 2021).
4
Online guides and forums: Online resources provide preparation guidance, including dosage recommendations, tips on setting and setting, and advice on managing challenging experiences (Baxter et al. 2024; Robinson et al. 2024) as well as guided meditations and exercises to cultivate a positive mindset and intentions (McAlpine et al 2024; 2024; 2024; Pilecki et al 2021)
6.6 Integration
Integration is crucial to help individuals process, make sense of, and apply insights from their psychedelic experiences to their daily lives, reducing the risk of harm and maximizing therapeutic potential (Bathje, Majeski, and Kudowor 2022; Cavarra et al 2022; Evans et al 2023; Gezon 2024; 2024; Hartogsohn 2021; Jivanescu 2022; Lutkajtis and Evans 2023; Walther and van Schie 2024; Garcia-Romeu and Richards 2018; Evens et al. 2023; “Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns - Mitch Earleywine, Fiona Low, Carmen Lau, Joseph De Leo, 2022,” n.d.). Integration can be particularly important when dealing with challenging or difficult experiences, as it provides a framework for understanding and integrating these experiences in a way that promotes healing and growth (Bathje, Majeski, and Kudowor 2022; Evans et al. 2023; Gezon 2024; Lutkajtis and Evans 2023; Argyri et al 2024; Bathje, Majeski, and Kudowor 2022; Breeksema et al 2022; Gorman et al 2021; O Robinson et al 2024; 2024) Some individuals experience integration challenges, often involving social disconnection and existential struggles It is important that these challenges are recognized, normalized, and addressed in a way that is helpful for the individual (Robinson et al 2024)
The Role of Integration in Reducing Psychedelic Risks and Harms
1 Meaning making: Connecting the psychedelic experience to personal values, beliefs, and life goals encourages the application of insights to improve well-being, relationships, and personal growth. (Bathje, Majeski, and Kudowor 2022; Gezon 2024; Jivanescu 2022; Bathje, Majeski, and Kudowor 2022; Cavarra et al. 2022; Gezon 2024; Jivanescu 2022; Walther and van Schie 202; CEvans et al 2023; Gorman et al 2021) Integration therapy offers a structured environment to process challenging experiences and make sense of them in a safe and supportive setting (Evans et al 2023; Gezon 2024; Lutkajtis and Evans 2023; Walther and van Schie 2024; Bathje, Majeski, and Kudowor 2022; 2022).
2. Preventing maladaptive beliefs: Integration reduces the risk of incorporating maladaptive or poorly formed beliefs into their worldviews (Zeller, n d ) The acute "epistemic softening" during a psychedelic experience can lead to a beneficial re-examination of beliefs, but without proper integration, this could lead to poorly formed beliefs (Zeller, n d )
3. Behavioral change: Integration aims to support lasting personal transformation beyond the immediate psychedelic experience, translating insights into positive behavioral changes (Bathje, Majeski, and Kudowor 2022; Cavarra et al 2022; Neitzke-Spruill 2022;
Garcia-Romeu and Richards 2018) This might involve adopting healthier habits, improving relationships, or pursuing new creative endeavors inspired by the experience (Bathje, Majeski, and Kudowor 2022; Cavarra et al 2022; Neitzke-Spruill 2022) Integration is viewed as a bridge between the psychedelic experience and daily life, fostering lasting behavior change (“Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns - Mitch Earleywine, Fiona Low, Carmen Lau, Joseph De Leo, 2022,” n.d.).
4 Addressing challenging experiences: Integration provides a structured way to work through difficult or challenging experiences that may arise during a psychedelic session (Garcia-Romeu and Richards 2018; Robinson et al 2024) Without integration, these challenging experiences can lead to extended difficulties such as derealization or panic attacks (Piercey et al. 2024).
5. Reducing disconnection and loneliness: Psychedelic experiences can sometimes evoke feelings of disconnection and loneliness (Cheung et al , n d ) Integration, especially in group settings or with peer support, provides a supportive community to address these feelings (Cheung et al , n d ; Bathje, Majeski, and Kudowor 2022; Cavarra et al 2022; Gezon 2024; 2024)
6. Promoting emotional and psychological well-being: By supporting the processing of insights, integration can contribute to improved emotional awareness, decreased anxiety, and increased emotional well-being (Garcia-Romeu and Richards 2018; Zeller, n d )
Specific Integration Measures and Techniques
● Early initiation and ongoing process: Integration should begin shortly after the psychedelic experience, typically within 1-2 days, to make the most of the ‘afterglow’ effect (Garcia-Romeu and Richards 2018) It is an ongoing process, not a one-time event, and should continue for weeks or months following the session (Evans et al 2023; Garcia-Romeu and Richards 2018)
● Personalized approach: Integration should be tailored to the individual’s unique experiences and needs, with a focus on what is most relevant to the individual (“Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns - Mitch Earleywine, Fiona Low, Carmen Lau, Joseph De Leo, 2022,” n d )
● Qualified facilitators: Integration should be facilitated by trained professionals who are knowledgeable about psychedelic experiences and integration techniques (“Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns - Mitch Earleywine, Fiona Low, Carmen Lau, Joseph De Leo, 2022,” n d )
● Therapeutic support
○ Individual therapy: Engaging in one-on-one therapy to discuss the psychedelic experience in depth, interpret its contents, and identify key themes aids in the practical application of insights into daily life and in turning those insights into
behavior change, especially after challenging experiences (Garcia-Romeu and Richards 2018).
○ Community support: Connecting with like-minded communities to share experiences, receive support, and learn from others can be particularly beneficial (Cheung et al , n d ; Robinson et al 2024)
● Mind-body practices
○ Contemplative practices: Regular meditation and prayer can aid the integration process.
○ Somatic practices: Engaging in practices such as yoga, qi gong, and breathwork to address somatic effects and facilitate integration
○ Nature: Spending time in nature was cited as a beneficial practice for many to help with integration
● Creative expressions: Creative outlets, such as art, music, writing, or journaling can be used to express and process the experience (Bathje, Majeski, and Kudowor 2022; Cavarra et al. 2022; Gezon 2024; O. Robinson et al. 2024; Piercey et al. 2024).
● Lifestyle adjustments
○ Diet and health: Making positive changes to one’s diet and health practices can be important parts of the integration process (Piercey et al 2024)
○ Regular routines: Working to maintain focus and stability by engaging with work, recreational activities, or creative projects can also facilitate integration (Robinson et al. 2024).
Examples of Effective Implementation
1 Psychedelic Therapy Models:
○ Aftercare meetings: These follow up meetings between the patient and therapists to discuss and reflect on the experience typically begin 1-2 days post-session (Garcia-Romeu and Richards 2018).
○ Ongoing integration sessions: These are weekly or bi-weekly meetings that last 1-3 months after the initial session for ongoing support, monitoring, and assistance in translating insights into behavior change (Garcia-Romeu and Richards 2018).
○ Narrative creation: Patients are invited to generate written narratives or artwork to help them remember and interpret their experiences (Garcia-Romeu and Richards 2018)
○ Mindfulness-based interventions: Combining integration with mindfulness-based therapies, like Acceptance and Commitment Therapy or Mindfulness-Based Relapse Prevention are often effective (Garcia-Romeu and Richards 2018).
2. Ayahuasca Integration:
○ Community integration: Individuals in ayahuasca churches often benefit from pre-existing communities, making integration less challenging Non-church
members need to often build their own supportive communities (Cowley-Court et al., 2023).
○ Somatic integration: There is evidence that somatic/physical integration modalities (e g , somatic-psychotherapy, breathwork, yoga) are particularly important for ayahuasca (Cowley-Court et al , 2023)
3 Peer Support Networks:
○ Online forums: Online forums for sharing harm-reduction information and experiences can be helpful in integration by providing accessible integration resources such as guided meditations, journaling prompts, and online communities to connect with others (O Robinson et al 2024; Baxter et al 2024)
○ Community-based integration groups: Facilitated groups offer peer support for sharing experiences, learning from others, and receiving guidance on integration practices (Gezon 2024; 2024; O. Robinson et al. 2024).
4 Retreat Centers:
○ Structured integration programs: These retreats offer programs specifically designed for integration, providing a supportive environment for reflection, processing, and connecting with others (Gezon 2024; 2024; O. Robinson et al. 2024).
○ Facilitated sharing: The opportunity to share one's experiences and story with a like-minded community can be a significant factor in effective integration(Cheung et al , n d )
● Clinical Trials: Integration is now considered a standard component of psychedelic-assisted therapy trials (Bathje, Majeski, and Kudowor 2022; Cavarra et al. 2022; Evans et al 2023; Walther and van Schie 2024; Gorman et al 2021; O Robinson et al. 2024).
6.7 Crisis Intervention and Emergency Response
Effective crisis intervention and emergency response strategies are crucial for mitigating acute adverse events during psychedelic sessions These strategies aim to ensure participant safety, manage distress, and prevent escalation to more serious situations The core principles involve creating a safe environment, providing reassurance, and having clear protocols for managing challenging experiences (Johnson et al 2019; “Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024)
It goes without saying that appropriate preparation can avoid crises to begin with, ideally eliminating the need for appropriate responses Preparation has been discussed extensively in multiple other sections of this document, most significantly in 6.5 above.
The most effective crisis intervention and emergency response strategies and protocols utilize a combination of non-pharmacological and pharmacological interventions.
Non-pharmacological interventions often serve as the first line of response and are crucial in de-escalating challenging experiences and promoting a sense of safety and support. They include:
1. Monitoring and reassurance:
○ Continuous monitoring: Maintaining continuous observation of participants throughout the session, including regular verbal contact (Carbonaro et al 2016)
○ Reassurance: Providing verbal reassurance that the experience is temporary, related to the drug effect, and that they are safe (Garcia-Romeu and Richards 2018). Empathetic listening, emotional support, and a calming presence can help the individual feel safe and grounded( Davis et al. 2022; Johnson, Richards, and Griffiths 2008) This is often sufficient to manage most cases of acute distress( Johnson, Richards, and Griffiths 2008).
○ Non-judgemental support: Ensuring participants feel accepted and validated, without judgement about their experiences (Robinson et al 2024; Garcia-Romeu and Richards 2018; Robinson et al. 2024). This helps in facilitating a feeling of safety during a difficult experience (Palitsky et al , n d )
2 Staying calm: Maintaining a calm and reassuring demeanor, as this can help reduce the participant's anxiety (“Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024; Garcia-Romeu and Richards 2018) Do not argue with or challenge the participant's altered perceptions, which can escalate distress (“Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024)
3 Providing simple guidance: Offering simple and clear instructions to help the participant focus, such as suggesting slow, deep breaths (“Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024) Encouraging the individual to focus on their breath, engage in guided imagery or meditation, or employ other grounding techniques learned during preparation. This can help shift their attention away from distressing thoughts and sensations (Ching et al 2024; McAlpine et al 2024)
4 Using gentle physical contact: If appropriate, offering gentle physical contact, such as a hand on the shoulder, to provide reassurance, with the participant’s consent (“Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024)
5. Managing the environment: Remove the participant from areas with excessive activity and noise Ensure the setting is quiet, dimly lit, and comfortable to minimize sensory stimulation This is crucial to reducing anxiety and promoting relaxation (Johnson, Richards, and Griffiths 2008; Barnett and Greer 2021; Ching et al. 2024; “Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF” 2024)
Pharmacological Interventions should be considered if non-pharmacological approaches are insufficient to manage the situation Proper medication administration by trained medical personnel can effectively reduce severe symptoms and ensure patient safety These medications can include:
○ Benzodiazepines: These are the preferred medication for managing acute psychological distress. Diazepam, with its rapid onset and shorter duration of action, is often recommended for its effectiveness in reducing anxiety and
agitation (Johnson, Richards, and Griffiths 2008; Barnett and Greer 2021) Another study stated that having benzodiazepine anxiolytics, such as diazepam, readily available as a first-line pharmacological intervention for cases where reassurance alone is not sufficient. An oral dose of 10 mg of diazepam is typically recommended, although higher doses (15-30 mg) may be necessary in emergency settings (Johnson, Richards, and Griffiths 2008)
○ Antipsychotics: Keep antipsychotic medications (e.g., risperidone, olanzapine) available as a last resort for severe cases that escalate to unmanageable psychosis However, these should be used with caution due to potential unpleasant and intense effects (Hughes & Matheson, 2016). They may be considered if the individual is experiencing severe agitation or psychosis that does not respond to benzodiazepines (Johnson, Richards, and Griffiths 2008; Barnett and Greer 2021). Some antipsychotics, like haloperidol, may exacerbate psychosis-like symptoms and should be avoided (Johnson, Richards, and Griffiths 2008).
○ 5-HT2A antagonists: The 5-HT2A antagonist ketanserin has shown promise in attenuating psilocybin effects However, ketanserin is not approved for use in the USA (Johnson, Richards, and Griffiths 2008).
Emergency Medical Services
Be prepared to contact emergency services if the participant’s condition does not improve with the above-listed interventions (Johnson, Richards, and Griffiths 2008) Emergency medical services should have clear protocols for assessing and managing psychedelic-related emergencies. Appropriate medication administration, in consultation with experienced clinicians, can be crucial for preventing escalation and harm (Johnson, Richards, and Griffiths 2008)
Documentation
Documenting all interventions and the participant's response will help inform future protocols and training (Hinkle et al. 2024; Rossi et al. 2022).
Examples of Effective Crisis Intervention and Emergency Response
1 Johns Hopkins University:
○ Safety Guidelines: Adherence to published guidelines for the safe administration of classic hallucinogens (Carbonaro et al 2016)
○ Session Management: Emphasizing that volunteers remain on the couch during sessions, and providing staff escorts to the restroom
○ Monitoring and Support: Staff members of the same gender stay immediately outside the restroom door, with intermittent verbal contact (Carbonaro et al. 2016)
○ Low Incident Rate: Despite administering psilocybin to 250 volunteers in more than 380 sessions, they experienced a very low rate of enduring psychological symptoms and were able to manage all cases of acute distress with reassurance alone(Carbonaro et al. 2016).
2 Clinical Trials:
○ Structured Protocols: Implementing structured preparation, monitoring, and integration protocols in clinical trials to minimize adverse events (O’Donnell, Grigsby, and Grob 2025; Evens et al 2023) In clinical trials, the presence of trained therapists or facilitators during psychedelic sessions allows for immediate and appropriate responses to challenging experiences (Ching et al 2024; Kirlić et al 2025; Neitzke-Spruill et al 2024; White et al 2024)
○ Use of Reassurance: Managing acute psychological distress primarily through verbal reassurance, with medication as a last resort (Johnson, Richards, and Griffiths 2008).
○ Standardized AE Assessment: Using standardized measures to evaluate and report acute and late adverse events, which enhances reliability and comparability of safety data across different studies (Freitas et al. 2024).
○ Low Rates of Serious AEs: Serious adverse events requiring medical or psychiatric attention are rare in monitored clinical settings (Hinkle et al 2024)
3. Psychedelic Helplines: These professionally-staffed helplines have been shown to successfully provide remote support to individuals experiencing psychedelic-related crises (Canady 2023; Kopra et al 2025) The can de-escalate challenging experiences and prevent the need for emergency medical services (Canady 2023).
4 Harm Reduction Organizations: Organizations like the Zendo Project, which provides psychedelic peer support at events, exemplify the effectiveness of trained volunteers in de-escalating challenging experiences(Móró and Rácz 2013)
Prevalence Data
● Emergency medical care: According to a recent survey, in 2020, approximately 1% of people who consumed LSD, 1% who consumed MDMA, 0 6% who consumed ketamine, and 0.6% who consumed psilocybin sought emergency medical care (Canady 2023).
● Serious AEs: Serious adverse events requiring medical or psychiatric attention are rare in monitored clinical settings, around 4% in participants with pre-existing neuropsychiatric disorders and 0% in healthy participants (Hinkle et al. 2024).
● Psychotic reactions: In early research, prolonged psychiatric reactions occurred in 1 out of 1200 non-patient participants, and 1.8 per 1000 psychiatric patients. Rates of developing psychoses following LSD administration have ranged from 08% to 4 6%, with higher rates among psychiatric patients (Johnson et al 2019;
● Suicide attempts and completions: Early research found no suicide attempts among 1200 non-patient participants, with suicide attempts and completed suicides occurring at respective rates of 1 2 and 0 4 per 1000 patients (Cohen, 1960)
● Challenging experiences: Even in controlled research settings, up to almost a third of participants have reported acute anxiety or fear during high dose sessions (Aday et al. 2020)
Important Considerations
● Context matters: The risk of adverse events is significantly higher in unsupervised and non-clinical settings. It's important to consider that these statistics may not translate to unsupervised recreational settings (Hinkle et al 2024)
● Underreporting: Adverse events may be underreported in research, so it’s important to use targeted questions and standardized measures to fully capture the scope of any negative experiences (Freitas et al 2024; Hinkle et al 2024; Palitsky et al , n d )
● “Challenging” vs. “adverse”: It's crucial to distinguish between challenging experiences, which can be a part of the therapeutic process, and true adverse events, which require intervention (Ehrenkranz et al 2024; Palitsky et al , n d ; Hinkle et al 2024).
6.8 Public Education
Public education plays a critical role in reducing risks and harms associated with psychedelic use. It empowers individuals to make informed decisions, encourages responsible use, and helps dispel myths and misinformation (Edwards et al 2023; Haden, Emerson, and Tupper 2016; Hartogsohn 2017; Kopra et al. 2022; Palamar and Acosta 2020). This education is essential because the effects of psychedelics can be profound and unpredictable, and a lack of accurate information can lead to increased risks (Kopra et al 2025)
Specific Educational Measures and Techniques:
● Harm reduction practices: Public education should emphasize harm reduction strategies, which include practices to reduce the likelihood of a challenging experience while under the influence of psychedelics (Baxter et al 2024) This involves education about starting with low doses, avoiding substance mixing, having a trusted "trip sitter," testing substances for purity, and understanding drug interactions (Edwards et al. 2023; Engel et al 2024; Lea, Amada, and Jungaberle 2020)
● Information on risks and benefits: Education efforts should provide accurate information about both the risks and potential benefits of psychedelics as well as their adverse effects (Kopra et al 2025; Ehrenkranz et al 2024) This empowers individuals to decide whether psychedelic use aligns with their needs and how to prioritize
safety(Edwards et al 2023; Haden, Emerson, and Tupper 2016; Palamar and Acosta 2020). It's important to present risks honestly to avoid misleading individuals about the safety of these substances (Ehrenkranz et al. 2024) and to ensure that materials are grounded in scientific evidence (Kopra et al 2025) This means relying on data from clinical trials, epidemiological studies and ensuring transparent and objective reporting of research findings by scientists and journalists is vital (Ehrenkranz et al 2024; Kopra et al 2025)
● Addressing misconceptions: Public education should provide evidence-based information to address myths and misconceptions. This combats fear-mongering and encourages a balanced, realistic view of psychedelic use (Haden, Emerson, and Tupper 2016; Kopra et al 2022; Pilecki et al 2021) It is important to emphasize that classic psychedelics like psilocybin and LSD bear almost no risk of overdose, long-term health effects, or addiction However, there is evidence that non-classical psychedelics like MDMA and Ketamine do have greater risk of overdose, long-term health effects and dependence, than classic psychedelics (Rajwani 2022).
● Importance of set and setting: Education should emphasize the importance of "set" (the user's mindset and expectations) and "setting" (the physical and social environment) in influencing the psychedelic experience (Bremler et al 2023; Henríquez-Hernández et al 2023; Edwards et al 2023; Kopra et al 2022; Robin L Carhart-Harris et al 2018; Garel et al. 2023; Haden, Emerson, and Tupper 2016; Palmer and Maynard 2022). A familiar, comfortable, and relaxed setting where the individual feels secure minimizes the risk of adverse psychological effects (Baxter et al. 2024).
● Targeted education for vulnerable populations: Groups such as young people, those with mental health conditions, or individuals exploring self-treatment might require distinct approaches (Edwards et al 2023; Haden, Emerson, and Tupper 2016; Izmi, Carhart-Harris, and Kettner 2024; Kruger, Glynos, et al. 2023; Bremler et al. 2023; Rajwani 2022). There is evidence that adolescents and young adults who use psychedelic drugs often lack access to medical and mental health services and counselling (Rajwani 2022)
● Accessibility and inclusivity: Educational resources should be easily accessible to the public This may involve using a variety of mediums, including online resources, brochures, community events, and educational programs (Robinson et al. 2024). In addition, educational efforts should be inclusive and address the needs of diverse communities (Haft et al. 2025). This includes accounting for cultural differences, socioeconomic factors, and varying levels of experience with psychedelics
● Clearly articulated guidelines for responsible use: This includes avoiding use during pregnancy or while breastfeeding, refraining from driving under the influence, and understanding the legal ramifications of the use of these substances (Haden, Emerson, and Tupper 2016; Lea, Amada, and Jungaberle 2020)
● Dangers of polydrug use: Education should warn against the dangers of polydrug use with psychedelics, as most psychedelic-related deaths involve multiple implicated drugs (Kopra et al 2025)
Examples of Effective Education:
● Peer-driven information: Utilizing peers as conduits for disseminating harm reduction information is effective, as many first-time users obtain information about LSD from friends This highlights the potential of harnessing peer support networks to promote safer practices and harm reduction Online forums can also be used as platforms for sharing harm reduction information (Baxter et al 2024)
● Training programs for first responders: The city of Denver launched a training program for first responders on “psychedelic crisis assessment and intervention” in partnership with the Multidisciplinary Association for Psychedelic Studies (MAPS) This is an example of an effective program that trains professionals who will be the first on scene for any adverse events (Kopra et al 2025)
● Psychedelic helplines: Providing access to a psychedelic helpline is another way to help de-escalate issues or prevent them altogether( Kopra et al. 2025).
● Drug testing services: Drug testing services can help to prevent adverse effects from unknown substances or impurities in what an individual believes to be a known substance (Kopra et al 2025).
Examples of Effective Implementation:
● Harm reduction organizations: Harm reduction organizations like the Zendo Project, DanceSafe, and the Multidisciplinary Association for Psychedelic Studies (MAPS) provide psychological support and education at events where psychedelics are commonly used. They offer a safe space for individuals experiencing challenging psychedelic experiences, helping to mitigate potential harm (Pilecki et al 2021; Edwards et al. 2023; Pilecki et al. 2021).
● Online platforms: Resources like Erowid and PsychonautWiki offer comprehensive, easily accessible information about different psychedelics This includes details about potential risks, benefits, and harm reduction advice (Pilecki et al. 2021; Palmer and Maynard 2022)
● Public health campaigns: Government-led public health campaigns, modeled after successful campaigns for alcohol and tobacco, can raise broader awareness about responsible psychedelic use These campaigns can also offer valuable resources for support and information(Haden, Emerson, and Tupper 2016) such as the importance of obtaining substances from trusted sources, utilizing test kits, and starting with low doses (Baxter et al 2024)
● Educational for Therapists: Organizations like the Multidisciplinary Association for Psychedelic Studies (MAPS) provide training for therapists and individuals working with psychedelics in clinical trials to equip practitioners with knowledge and skills to promote safe and effective psychedelic use (Pilecki et al. 2021).
Prevalence Data:
● Approximately 8 5 million Americans over the age of 12 endorsed past year psychedelic use in 2022, with 1.4 million individuals initiating use during this time(Piercey et al. 2024).
● In the US, approximately 22% of adults have tried psychedelics(Palitsky, Canby, et al , n d )
● Epidemiological research suggests that 9-13% of non-clinical trial psychedelic users have experienced negative outcomes that involved some degree of functional impairment in the days or weeks after dosing(Palitsky, Canby, et al., n.d.; Palitsky, Kaplan, et al., n.d.).
● 2 6% of non-clinical trial users have required medical, psychiatric, or psychological assistance(Palitsky, Canby, et al , n d ; Palitsky, Kaplan, et al , n d )
● The number of poison control cases involving psilocybin tripled between 2018 and 2022(Palitsky, Canby, et al , n d )
● The number of hallucinogen-related emergency department visits and hospitalizations increased by 54% and 55%, respectively, from 2016 to 2022(Palitsky, Canby, et al., n.d.).
● In a recent Phase IIb trial of psilocybin, approximately 5% of patients experienced serious adverse events, including suicidality(Palitsky, Kaplan, et al , n d )
6.9 Online Communities
Online communities play an important role in reducing psychedelic risks and harms by providing users with information and support (Edwards et al. 2023; Engel, Thal, and Bright 2022a; 2022a; Gezon 2024; 2024; 2024; 2024; Lea, Amada, and Jungaberle 2020; 2020; McAlpine et al 2024; Miller et al 2024; Móró and Rácz 2013; Pedersen and Steglich-Petersen, n d ; Bøhling 2017; Baxter et al. 2024).
Specific Factors and Conditions in Online Communities That Reduce Risk and Harms:
● Harm reduction information sharing: Online communities are vital for disseminating harm reduction techniques. Members frequently share advice on safe dosing, set and setting, and what to do in case of a challenging experience (Baxter et al 2024; Lea, Amada, and Jungaberle 2020) The constant exchange of practical, experience-based advice helps users mitigate risks associated with psychedelic use (Bøhling 2017; Baxter et al 2024; Edwards et al 2023)
● Peer support and experience sharing: Online forums provide supportive environments where users share their experiences, both positive and negative (Baxter et al. 2024; Edwards et al 2023; Engel, Thal, and Bright 2022a; Gezon 2024; 2024; 2024; 2024; Lea, Amada, and Jungaberle 2020; 2020; Móró and Rácz 2013; Engel, Thal, and Bright 2022b) This sharing helps normalize the psychedelic experience and provides a sense of community (Cheung et al , n d ; Baxter et al 2024) For example, individuals experiencing difficulties after psychedelic use can find validation and support, reducing feelings of isolation and disconnect (Cheung et al., n.d.; Evans et al. 2023). These
communities can be particularly beneficial for those who may not have access to traditional support systems (Cheung et al., n.d.).
● "Bottom-up" knowledge and alternatives: Online drug communities function as peer-based, bottom-up technologies that facilitate the construction and diffusion of alternatives to the hegemonic narrative of prohibition This includes promoting the idea that seeking pleasure through drug use is normal and can be compatible with concerns about safety and harm reduction (Bøhling 2017) Online communities can therefore act as a bridge between more official (but potentially less approachable) resources and individuals (Baxter et al. 2024).
● Discussion of drug interactions: Online forums can facilitate the sharing of information regarding drug interactions, including potentially dangerous combinations Members might discuss the potential risks of combining psychedelics with other substances, including alcohol or medications (Polito and Liknaitzky 2022)
● Identification of novel practices: Online communities can act as early detectors of new trends and practices in the use of psychedelics. This allows researchers and harm reduction advocates to monitor and respond to emerging issues quickly (Rosenbaum et al, 2020)
● Information on set and setting: Users within these communities often discuss the importance of “set” (mindset) and “setting” (environment) in influencing the psychedelic experience. These discussions can help guide others in preparing for their experiences to minimize the risk of adverse effects (Baxter et al. 2024).
● Moderation and community guidelines: Some online forums (e.g., PsychonautWiki) have established guidelines and moderation practices that are designed to support harm reduction These practices might include removing posts that promote unsafe practices, sharing inaccurate information, or encourage behavior that could be potentially harmful to others in the community.
● Facilitating access to services: Online communities can also help users access services and connect with professionals that are more difficult to find through other means, such as psychedelic-friendly therapists
● Discussions of challenging experiences: Users can share their experiences of difficult psychedelic trips, and learn from the experiences of others. This can help to reduce the stigma associated with challenging experiences, and to promote healing and integration (Gezon 2024)
Examples of Effective Education Within Online Communities:
● Trip reports: Online communities host trip reports, which are detailed accounts of users’ experiences These reports can offer valuable insights into the range of potential effects of a given substance, help others prepare for their own experiences, and aid integration They can also shed light on both the pleasurable aspects of drugs and on the ways in which these experiences are shaped by the contexts of use and the activities of the users (Bøhling 2017)
● Q&A and discussion threads: Many online forums have specific threads dedicated to harm reduction, dosage guidance, or common questions about psychedelics. These threads allow new users to ask questions and get practical, real-time answers from more experienced users (Baxter et al 2024)
● Visualizations: Some online communities use images and visualizations to help communicate complex concepts related to set, setting and the potential effects of psychedelics (Polito and Liknaitzky 2022)
● Resources for psychedelic users: Online communities can develop resources for psychedelic users, such as guides to safe use, trip sitter guidelines, and integration resources(Lea, Amada, and Jungaberle 2020; McAlpine et al 2024; 2024; Edwards et al 2023) These resources which can include links to other resources for harm reduction, such as websites, articles, and videos can help to empower users to make informed decisions about their use, and to reduce the risks associated with psychedelic use (Baxter et al. 2024). This is especially important given the amount of misinformation that is available online (Pilecki et al. 2021).
Best Practices for Online Communities to Reduce Psychedelic Harms:
● Prioritize moderation: Active moderation helps to ensure that harm reduction advice is accurate and that misinformation is quickly addressed (Cheung et al., n.d.). Moderators should be knowledgeable about psychedelics and committed to safety.
● Promote inclusivity: Online communities should be open and welcoming to all users regardless of their experience level This ensures that newcomers feel comfortable asking questions and seeking help (Baxter et al 2024)
● Encourage diverse perspectives: Communities should strive for diverse viewpoints and acknowledge that not all experiences will be the same. This can be supported by facilitating conversations with a wide range of participants who have varying levels of experience with psychedelics (Cheung et al., n.d.).
● Highlight lived experiences: Online communities should emphasize the importance of lived experiences when communicating about risks and benefits of psychedelic use By leveraging the power of peer support networks, safer practices can be promoted and harm reduction can be increased (Baxter et al. 2024).
● Provide clear guidelines: Clear and easy-to-understand guidelines for community participation should be established. These should include information about acceptable and unacceptable behavior and how the community members treat one another (Cheung et al , n d )
● Integrate official resources: Online communities should be encouraged to integrate official resources such as links to psychedelic helplines, drug testing services, and public health websites. This can help users access additional support services (Canady 2023; Kopra et al. 2025).
● Address misinformation: Steps should be taken to address misinformation or unsafe practices as soon as they are identified This could include removing posts, providing corrections, or highlighting safe use practices (Cheung et al , n d )
● Promote critical thinking: Users should be encouraged to think critically about information they see online. The limitations of anecdotal evidence should be acknowledged while also respecting the value of lived experience (Miceli McMillan 2022)
● Avoid "exceptionalizing" psychedelics: It is important to avoid the perception that psychedelics are unique in their risks or challenges There are many things that can be learned from other types of peer support groups (Cheung et al , n d )
● Monitor trends: Online communities should continuously monitor discussion threads for new trends in substance use or potential safety issues. (Rosenbaum et al 2020)
Limitations of Online Communities:
While online communities offer substantial benefits, there are also risks that should be acknowledged (Cheung et al., n.d.), listed below:
● Misinformation: There is always a risk of exposure to inaccurate or misleading information Not all users are equally knowledgeable, and some may share unsafe practices (Cheung et al , n d )
● Cultic dynamics: Online communities, like any group setting, can potentially develop cultic social dynamics. The suggestibility-enhancing properties of psychedelics can make users vulnerable to manipulation or exploitation (Cheung et al., n.d.).
● Lack of regulation: Many online communities are not regulated and lack oversight, which means that users can be exposed to harmful content and unsafe advice
● Limited verification: It's difficult to verify the information and experiences shared by members, and some users may misrepresent their qualifications (Rosenbaum et al 2020)
● Absence of professional guidance: While peers can offer support, online communities cannot replace professional medical or therapeutic advice (Cheung et al., n.d.).
● Potential for echo chambers: The nature of online communities may lead to echo chambers where participants primarily interact with like-minded people, and where dissenting viewpoints may be disregarded or suppressed, leading to a potential blind spot for new users (Kim, 2023).
Prevalence Data:
● One online microdosing forum on Reddit has almost 40,000 subscribers and doubled its subscriber count in one year (Anderson et al 2019)
6.10 Peer Support Networks
Peer support networks play a crucial role in reducing psychedelic risks and harms by providing accessible, non-judgmental support, practical guidance, and a sense of community for
individuals navigating psychedelic experiences (Cheung et al , n d ; Kopra et al 2025) These networks, often composed of individuals with lived experience, offer unique advantages in harm reduction that complement traditional medical and therapeutic approaches Examples of these peer support networks include the Fireside Project and Zendo Project, both of which offer support in various forms such as phone helplines and on-site assistance at events (Cheung et al , n d ; Kopra et al 2025)
Role of Peer Support Networks in Reducing Psychedelic Risks and Harms:
● Accessible and non-judgmental support: Peer support networks provide a safe and confidential space for individuals to discuss their psychedelic experiences without fear of stigma or judgment (“How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024). This is especially important given the historical criminalization of psychedelics, which can make people hesitant to seek help from traditional sources (“How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe?” 2024; Palitsky et al , n d ) Peers can often build trust more easily and establish rapport due to their shared experience (Cheung et al., n.d.).
● Real-time support and crisis intervention: Peer support networks offer immediate assistance during challenging psychedelic experiences via telephone, offering guidance and de-escalation techniques to individuals experiencing distress (Canady 2023; Kopra et al 2025) This can prevent the escalation of negative experiences and reduce the need for emergency medical services (Canady 2023)
● Integration support: Peer support networks facilitate the integration process by providing a community where individuals can share their experiences and gain support in making sense of them (Cheung et al , n d )
● Community and connection: Psychedelic experiences can sometimes lead to feelings of isolation or disconnection (Evans et al , 2023) Peer support networks address this by fostering a sense of community where individuals can connect with others who understand their experiences, and offering a supportive community of individuals who understand their experiences (Modlin et al., 2025). This sense of belonging can reduce feelings of loneliness and help individuals feel more comfortable navigating the integration process (Cheung et al , n d )
● Harm reduction education and guidance: Peers often share practical advice based on their own experiences, including tips on safe dosing, set and setting, and how to manage challenging experiences. This lived experience provides a valuable complement to formal educational materials and ensures information is communicated in a more approachable manner (Baxter et al 2024; Piercey et al 2024) By fostering a culture of safety, these networks can help reduce harm associated with psychedelic use (Baxter et al 2024; Piercey et al 2024)
● Bridging gaps in services: Peer support can fill gaps in existing healthcare systems by providing support outside of traditional therapeutic settings. This is important because formal psychedelic therapy may not always be accessible or affordable, and/or some
individuals may prefer alternative or supplemental forms of support (Cheung et al , n d ; Robinson et al. 2024).
● Reducing burden on emergency and support services: By providing timely support, peer networks can potentially reduce the number of individuals who might otherwise seek help in emergency rooms This is a valuable benefit to the community overall, since it allows limited resources to be more efficiently allocated (Canady 2023) In addition, collaboration between peer support networks, medical professionals, and harm reduction organizations can enhance the impact of support services (Glynos et al. 2023; Pilecki et al. 2021).
Specific Peer Support Measures and Techniques:
● Active listening and validation: Peers provide a non-judgmental space for individuals to express their experiences and emotions. They often focus on actively listening to validate an individual's feelings This validation can be especially helpful for those who have experienced challenging or unusual effects (Baxter et al 2024)
● De-escalation and reassurance: Peers can provide guidance and reassurance to help individuals navigate the challenging moments This can include using calming techniques, such as breathing exercises and gentle redirection, and providing reassurance that the experience is temporary (Henningfield et al. 2023).
● Sharing of lived experiences: Peers share their own experiences to normalize the psychedelic process and provide context for difficult feelings that may arise This helps individuals feel less alone and more understood (Cheung et al , n d ) These groups offer a platform for individuals to share their experiences, connect with others who understand, and learn from each other (Gezon 2024; O. Robinson et al. 2024).
● Practical guidance on harm reduction: Peers provide advice on practical steps to mitigate risks, such as avoiding co-use of multiple substances, and taking psychedelics in a comfortable, secure setting These practical steps are often based on lived experiences within these communities (Lancelotta and Davis 2020; Baxter et al 2024; Piercey et al 2024)
● Integration support: Peer supporters facilitate the integration process by discussing the experiences and providing tools and techniques for incorporating insights from a psychedelic experience into their daily life (Evans et al. 2023; Gezon 2024; O. Robinson et al 2024)
● Referral to professional services: Peer support networks are aware of their limitations and provide referrals to more formal therapeutic or medical services when needed This helps ensure individuals have access to the appropriate level of care (Cheung et al., n.d.; Kopra et al. 2025; Canady 2023).
● "Trip sitting": Peers are often present during a psychedelic experience to ensure the safety and well-being of the individual, sometimes referred to as trip-sitting Trip sitters act as guides to provide reassurance, assist with practical needs, and help to navigate challenging emotional states( Baxter et al 2024; Edwards et al 2023; Palmer and Maynard 2022).
● Educational resources: Peer support networks help curate or create educational materials to help users become more informed. These materials might be in the form of articles, videos or other useful guidance, and often emphasize the importance of safety, harm reduction, and integration of the psychedelic experience( Cheung et al , n d ; Robinson et al 2024; Gezon 2024; Kruger, Enghoff, et al 2023; Shaw et al 2023)
Examples of Effective Implementation:
● Fireside Project: This non-profit organization operates a peer support telephone helpline for individuals experiencing difficult psychedelic experiences (Kopra et al. 2025; Canady 2023; Pleet et al 2023) Fireside Project's data shows that their helpline successfully de-escalated 65 9% of callers from psychological distress, demonstrating the potential of remote peer support in reducing psychedelic-related harms (Pleet et al 2023). Of the callers, 29.3% reported that they may have been harmed, 12.5% would have potentially called 911, and 10.8% might have gone to the emergency room if they hadn’t had support from Fireside Project (Pleet et al. 2023; Canady 2023).
● Zendo Project: The Zendo Project is a psychedelic harm reduction organization that provides on-site peer support at festivals and events, offering a safe space for individuals experiencing challenging psychedelic states (Ruane 2015) They have been successful at reducing the need for medical or emergency support at these events (Cheung et al., n.d.; Golden et al. 2022). Their volunteers, known as "sitters," have experience with psychedelics and view them as tools for personal growth when used responsibly (Ruane 2015; 2015)
● Integration groups: Many communities offer facilitator-led integration groups, where participants can share experiences with peers These groups can be particularly effective for supporting ongoing integration and building community (Cheung et al., n.d.).
● Online peer forums: Peer support networks are often found within online communities, where members share information on harm reduction, integration, and personal experiences These online forums are an important resource for many individuals who seek information on psychedelic substances (Baxter et al 2024) For more information about these, please see section 6 9 above
Best Practices for Psychedelic Peer Support:
● Training and Supervision: Peer supporters should receive adequate training and ongoing supervision Training should cover topics such as active listening, de-escalation techniques, and harm reduction principles, with an emphasis on ethical practices( Kopra et al 2025; Evans et al 2023)
● Emphasis on Empathy and Non-Judgment: Peer supporters should demonstrate empathy, acceptance, and non-judgment towards individuals. They should be trained to provide support without imposing their own beliefs or values
● Cultural Sensitivity and Inclusion: Peer support networks should strive to be culturally sensitive and inclusive. They should be aware of the unique challenges faced by diverse communities and work to provide culturally appropriate support (Barber and Dike 2023).
● Clear Boundaries and Ethical Guidelines: Peer support networks should establish clear boundaries and ethical guidelines to ensure the safety and well-being of all participants This includes protecting confidentiality, avoiding conflicts of interest, and being aware of potential power dynamics (Cheung et al , n d )
● Collaboration with Professionals: Peer support networks should collaborate with mental health professionals to provide seamless support. This could include providing referrals to therapists, medical providers, or other relevant professionals (Cheung et al , n d ; Kopra et al 2025; Canady 2023)
● Evidence-Based Practices: Peer support networks should be committed to adopting evidence-based best practices This includes monitoring outcomes and adapting techniques based on research and feedback (Cheung et al., n.d.).
● Focus on Integration: Support should not only be during the experience itself, but also post-experience to support integration The focus should be placed on helping individuals apply their experiences to their daily lives (Cheung et al , n d )
● Promote Self-Education: Peers should be trained to help others access resources and information they can use to promote their own self-education This is important to support long-term positive outcomes and individual agency.
● Avoid Misinformation: Peer supporters should be trained to help counter misinformation, and provide evidence-based information. Emphasis should be placed on responsible information sharing (Kopra et al 2025; Piercey et al 2024; Baxter et al 2024)
● Address Systemic Issues: Peer support networks should address systemic issues that may contribute to psychedelic-related harms, such as stigma and limited access to resources. This can be done by promoting policy changes and advocating for the rights of people who use drugs (Cheung et al., n.d.).
● Promote Self-Care: Peer supporters should be aware of the potential for emotional and psychological strain that may accompany this role They should be encouraged to practice self-care to ensure they are able to continue providing support (Cheung et al , n.d.).
● Data Collection and Analysis: To measure effectiveness, peer support networks should systematically collect and analyze data on their activities and outcomes. This can provide insight into ways to improve services and further reduce harms (Cheung et al , n d )
● Continuous Improvement: Peer support networks should adopt an approach of continuous improvement. This could include feedback loops, training, and ongoing learning (Cheung et al., n.d.).
Limitations of Peer Support Networks:
● Lack of regulation: Many peer support networks are not regulated and do not have oversight, which may leave them open to certain risks and harms (Cheung et al., n.d.).
● Variable quality: The quality of peer support may vary depending on the skills and training of the individual involved (Cheung et al , n d )
● Potential for cultic dynamics: Like any group setting, peer support networks can be subject to cultic social dynamics There is a need to address this potential risk by implementing appropriate training, education and oversight (Cheung et al , n d )
● Absence of professional care: While peer support can be valuable, it should not be seen as a replacement for professional medical or therapeutic interventions (Cheung et al , n d ; Kopra et al 2025; Canady 2023)
● Potential for bias: Peer supporters bring their own biases and lived experiences to the process, which could unintentionally influence the guidance or support they provide (Cheung et al , n d )
● Limitations of lived experience: While lived experience is valuable, it's also important that peer supporters do not represent their own experience as universal or generalizable (Cheung et al , n d )
6.11 Accessibility and Inclusion
Accessibility, inclusion, and equity (AIE) are crucial for reducing psychedelic risks and harms by ensuring diverse populations can access safe and culturally sensitive support (Gezon 2024; 2024; Pilecki et al. 2021). Neglecting these considerations could increase the risk of negative outcomes for marginalized communities (Gezon 2024; Pilecki et al 2021)
Accessibility
● Financial barriers: The high cost of psychedelic therapies, often reaching AUD $25,000 per treatment course, can create barriers to access for individuals with limited financial resources (Barber, Gardner, and Carter 2024; 2024) This financial barrier could lead to a system where only wealthy individuals benefit from psychedelic treatments (Barber, Gardner, and Carter 2024; Barnett and Greer 2021; Fonzo, Nemeroff, and Kalin 2025). Some individuals pay out of pocket for psilocybin treatments if they are not covered by insurance or other subsidies (“Longitudinal Experiences of Canadians Receiving Compassionate Access to Psilocybin-Assisted Psychotherapy,” n d ) Equitable access requires innovative solutions like group therapy, exploring insurance coverage, and developing more cost-effective treatment protocols (Barnett and Greer 2021). For example, the time-intensive nature of psychedelic therapies could be addressed through group therapy approaches, which could potentially increase access and reduce costs (Barnett and Greer 2021)
● Logistical barriers: Participation in psychedelic trials can be time-consuming and resource-intensive, which may be prohibitive for those with inflexible work schedules or
lack of transportation Logistical barriers to participation in trials may include language barriers as well, which can impact enrollment and study procedures (Haft et al. 2025.)
● Geographic barriers: Access to psychedelic therapy can be limited by location, with a lack of availability in rural or underserved areas (Golden et al 2022) Addressing geographic disparities could involve integrating telehealth or mobile clinics to reach remote populations (Gezon 2024)
Inclusion
● Racial and ethnic diversity: Clinical trials have historically underrepresented Black and Hispanic/Latino participants Studies show that 82 3% of participants in clinical psychedelic studies between 1993 and 2017 identified as non-Hispanic White This lack of representation limits the generalizability of research findings and may lead to treatments that are not effective or culturally appropriate for all populations (Barber and Dike 2023). In another study, Black/African-American participants made up only 12.2% of trial participants, and Hispanic/Latino participants made up 7.2%. MDMA trials have shown slightly more racial diversity than psilocybin trials (Haft et al 2025)
● Socioeconomic status: Individuals with higher levels of education are overrepresented in psychedelic trials, while those with lower socioeconomic status are underrepresented This can lead to interventions that are not tailored to the needs of disadvantaged communities. (Haft et al. 2025).
● Sexual orientation and gender identity: Sexual orientation and gender identity are frequently unreported in trials, despite the fact that these minority groups are at a higher risk of mental health disorders Only 9 5% of studies reported participant sexual orientation, and no studies reported gender identity This omission makes it difficult to understand the impact of psychedelic interventions on these populations. (Haft et al. 2025).
● Immigrant status: Immigrant status is rarely reported in psychedelic trials (4.8%). Language barriers and cultural differences can create unique challenges for immigrants to participate in and benefit from these therapies (Haft et al 2025)
● Cultural competence: The "set and setting" of a psychedelic experience are heavily influenced by cultural factors (Bremler et al. 2023; Gezon 2024; Pilecki et al. 2021; Breeksema et al. 2022). Ignoring these factors can lead to misinterpretations, inappropriate interventions, and even harm(Breeksema et al. 2022). A lack of cultural sensitivity in therapeutic settings can lead to negative experiences and undermine the potential benefits of psychedelics, and current treatment settings may not promote positive outcomes for racial and ethnic minorities (Jones and Nock 2022) Therefore, training programs and educational resources must emphasize cultural sensitivity and adapt therapeutic approaches to meet the diverse needs of patients (Dupuis and Veissière 2022; Gezon 2024; Pilecki et al. 2021).
● Recognizing and respecting traditional knowledge: The increasing interest in therapeutic applications of psychedelics should acknowledge and respect the long-standing traditions of indigenous cultures that have used these substances for
centuries (Pilecki et al 2021; Dupuis and Veissière 2022; Haden, Emerson, and Tupper 2016). Engaging with indigenous communities, ensuring benefit-sharing, and avoiding cultural appropriation are crucial for ethical and equitable development of psychedelic therapies (Pilecki et al. 2021; Dupuis and Veissière 2022).
Equity
● Historical and systemic factors: Past injustices and systemic oppression, including the War on Drugs, can impact the mindset of individuals from minoritized groups, which may impact clinical outcomes. Historical abuse of minority populations in medical research also affects attitudes toward participation in trials (Jones and Nock 2022).
● Harm reduction: Harm reduction strategies need to be tailored to the specific needs of different communities For example, outreach and education efforts should be designed with an understanding of the unique challenges faced by marginalized groups, including issues of distrust of medical institutions and law enforcement (Jegede et al. - 2024).
● Community engagement: Engaging community members in the design and implementation of psychedelic research can help build trust and ensure that treatments are appropriate and relevant to diverse populations Culturally sensitive and respectful treatment approaches are also critical This includes including voices from target demographic groups early in the research process (Haft et al 2025)
Best Practices for Reducing Harm through Accessibility, Inclusion, and Equity
● Increase diversity in clinical trials: Clinical trials for psychedelic therapies often lack diversity among researchers, therapists, and participants, limiting the generalizability of findings (Pilecki et al 2021; Edelsohn and Sisti 2023; Wang et al 2024) Researchers must actively recruit participants from diverse racial, ethnic, socioeconomic, sexual orientation, and gender identity backgrounds (Barber and Dike 2023; Muthukumaraswamy, Forsyth, and Sumner 2022), in order to ensure research findings are relevant and applicable to diverse populations (Pilecki et al 2021; Edelsohn and Sisti 2023) Financial compensation for participants and reimbursement of study-related costs, a diverse clinical staff, targeted outreach and recruitment strategies, and an addressing of systemic barriers to participation in research can help increase enrollment among minoritized groups (Pilecki et al. 2021; Edelsohn and Sisti 2023).
● Develop culturally adapted interventions: Develop psychedelic-assisted therapies that take into account the cultural, spiritual, and historical backgrounds of participants This may involve adapting the language, therapeutic approach, and integration practices to be more culturally relevant (Piercey et al 2024)
● Promote community engagement: Support community-based programs and harm reduction strategies tailored to the specific needs of different groups (Piercey et al. 2024). This could include peer-to-peer support, culturally relevant education, and accessible resources (Piercey et al 2024)
● Provide accessible information: Develop and disseminate educational materials about psychedelics in multiple languages and formats. Ensure that information is accessible to individuals with varying levels of health literacy, and that it is non-judgmental (Rajwani 2022)
● Address stigma: Acknowledge and address the stigma associated with mental health issues and substance use, particularly within marginalized communities Emphasize a harm reduction approach that respects the autonomy and agency of individuals who use psychedelics (Rajwani 2022).
● Standardized measures: Use standardized measures and data collection methods that are culturally sensitive and inclusive when assessing adverse events (Palitsky et al , n d ; Freitas et al 2024) This includes using tools designed to assess social determinants of health in clinical settings
Examples of Effective Implementation Strategies for AIE:
● Community-based integration groups: Peer-led groups provide affordable, accessible settings for integrating psychedelic experiences (Gezon 2024) by fostering support and the sharing of experiences and promoting understanding. These measures ultimately reduce stigma and increase accessibility (Gezon 2024)
● Culturally adapted therapies: Adapting therapies to specific cultural contexts enhances safety and efficacy (Gezon 2024; Pilecki et al 2021) For instance, modifying MDMA-assisted psychotherapy to acknowledge the potential mistrust of medical systems among marginalized communities can improve patient engagement and outcomes (Pilecki et al 2021) This could involve spending more time during initial screenings to build rapport and address potential concerns (Pilecki et al 2021)
● Harm reduction organizations: Organizations like the Zendo Project and Fireside Project prioritize non-judgemental support and harm reduction (Gorman et al 2021; Palmer and Maynard 2022) For more information about these, see section 6 10 above
7. Research Gaps
A number of significant research gaps exist in the current literature on psychedelic safety and risks, which limit the effectiveness of harm reduction measures (Palitsky et al., n.d.). These gaps, explored below, span multiple areas, including the need for more diverse study populations, standardized reporting of adverse events, a better understanding of long-term effects, and further exploration of the impact of set and setting on outcomes (Golden et al 2022; Palitsky et al , n d ; Golden et al 2022)
1. Limited Diversity in Study Populations:
● A significant research gap is the lack of diversity in psychedelic clinical trials (Aday et al 2020) Most studies predominantly include white, educated, middle-aged participants,
leading to a lack of generalizability of findings This homogeneity fails to account for the varied responses across different racial, ethnic, and socioeconomic groups. For example, a review of psychedelic studies between 1993 and 2017 found that 82.3% of participants identified as non-Hispanic White Haft et al 2025)
● Individuals from marginalized communities experience chronic stress and bear a disproportionate burden of mental illness, which may influence treatment acceptability and outcomes The absence of BIPOC in research creates a vacuum in data that is crucial for understanding ethnoracial factors influencing psychedelic experiences (Fogg et al., 2021).
● There is underrepresentation of low-income individuals, those with diverse sexual orientations, and those with pre-existing conditions, further limiting the scope of current research Less than 4% of RCTs for suicide and self-injury report participant sexual orientation, highlighting this gap (Haft et al 2025)
● This lack of diversity means that the current understanding of psychedelic safety and efficacy may not apply to the broader population (Aday et al. 2020; Aday et al. 2021; Bălăeţ 2022a; Gomez-Escolar et al 2024; Kruger, Glynos, et al 2023; Peterson et al 2023; Raison et al 2022) There is also a critical need to understand how specific identity factors impact the associations between psychedelic use and mental health outcomes
2. Inconsistent and Undereported Adverse Events:
● Current adverse event (AE) reporting in psychedelic research is inconsistent, with many studies focusing only on limited negative effects such as fear, anxiety, paranoia, and depression A detailed, comprehensive study on the phenomenology of enduring psychedelic-related AEs has yet to be conducted (Palitsky et al., n.d.).
● There is a lack of standardized and tailored assessments for adverse events (AEs) in psychedelic research, making it challenging to comprehensively understand and mitigate the risks associated with these therapies (McIntyre et al 2025; Palitsky et al , n d ; Simonsson, Goldberg, and Hendricks 2024). Descriptions of settings and setting-components varied considerably in their specificity and replicability (Golden et al 2022). This inconsistency limits the synthesis of evidence across studies and hinders the development of best practices
● Many studies fail to capture post-acute dosing impacts of psychedelics on subjective states, meaning, and psychosocial health variables Domains such as influences on spirituality, worldviews, and identity, which are often discussed as positive effects, are omitted from AE assessments, despite the possibility of negative impacts (Golden et al. 2022)
● Psychotherapy-related AEs are consistently not assessed or undocumented in psychedelic-assisted therapy (PAT), despite the emphasis on combining psychedelics with psychotherapy There is a need to better understand the risks associated with psychedelics, especially for individuals with pre-existing vulnerabilities (Palitsky et al., n.d.).
Limited Understanding of Long-Term Effects:
● Most research focuses on short-term outcomes, creating a significant knowledge gap regarding long-term effects, including potential persistent perceptual disturbances or mental health issues, the durability of therapeutic effects, and the emergence of delayed AEs (McIntyre et al 2025; Bălăeţ 2022a)
● More research is needed on the potential for Hallucinogen Persisting Perception Disorder (HPPD) and other enduring psychological and perceptual disturbances (Aday et al. 2020).
● It is important to assess potential shifts in worldviews, identity, and spirituality, as these could be both beneficial and distressing (Golden et al 2022)
4. Lack of Understanding of the Impact of "Set and Setting":
● The context, including the psychological and environmental setting, significantly influences the therapeutic action of psychedelics (Carhart-Harris et al. 2018; Aday et al. 2020) Neglecting this context can render psychedelic experiences ineffective or potentially harmful There is, however, a lack of empirical studies rigorously testing the effects of setting (Aday et al 2020; Armstrong and Davis 2024; Bălăeţ 2022a; Dupuis and Veissière 2022; Kishon et al. 2024; Pedersen and Steglich-Petersen, n.d.).
Research systematically examining the impact of set and setting, investigating the influence of various environmental and contextual factors on outcomes, and developing guidelines for creating safe and supportive environments (Bălăeţ 2022b) is needed
● The descriptions of settings in research vary widely and lack specificity, which limits replication of findings A better understanding of how set and setting impact outcomes is needed to develop best practices (Aday et al. 2020; Bremler et al. 2023; Ghaznavi et al. 2025; Golden et al. 2022; Haden, Emerson, and Tupper 2016; Haijen et al. 2018; Hartogsohn 2017; McAlpine et al. 2024; Noorani 2021; Palmer and Maynard 2022).
5. Challenges in Clinical Trial Design:
● There are methodological challenges in designing high-quality clinical trials with psychedelics, including the difficulties in selecting a proper placebo and accounting for expectancy effects (Gukasyan et al. 2022). Yet, the placebo response in psychedelic studies can reach up to 40% Understanding the placebo response is crucial to accurately measure the effectiveness of psychedelic substances (Gukasyan et al 2022)
● There is a lack of adequate control conditions Some experiments use active comparators (e g , amphetamines) or low doses of hallucinogens, making it challenging to assess the efficacy of psychedelics (Gukasyan et al. 2022).
● The influence of "set and setting" on the efficacy of psychedelic substances complicates clinical trial design Adhering to evidence-based regulatory guidelines is essential (Gukasyan et al 2022)
● The subjective nature of psychedelic experiences makes designing rigorous studies with appropriate controls and blinding procedures difficult, impacting the ability to draw definitive conclusions about efficacy and safety (Armstrong and Davis 2024; Pedersen and Steglich-Petersen, n.d.; Fonzo, Nemeroff, and Kalin 2025; Hendy 2018; Gukasyan et al 2022; Aday et al 2022)
6. Gaps in Microdosing Knowledge :
● Despite increasing popularity, research on microdosing's effects, safety, and potential risks remains limited (Anderson et al 2019; GCU, Lahore, Pakistan and Shabir 2024; Gomez-Escolar et al 2024; Petranker et al 2022) Conducting rigorous research on microdosing, exploring its long-term effects, safety profile, optimal dosing strategies, and potential risks (GCU, Lahore, Pakistan and Shabir 2024) is necessary
● While microdosing is gaining popularity, there is a lack of consensus about what constitutes a microdose. The effects of microdosing are difficult to predict and are not directly related to body weight (Kuypers et al., 2019).
● Most research on microdosing relies on self-reporting and is often not placebo-controlled These studies lack experimental control and can be subject to sampling bias (Savides and Outhoff 2024)
● Research on the potential cardiac risks associated with microdosing practices, such as the partial agonism of the 5HT-2B receptor, and its role in drug-induced cardiac fibrosis, valvular heart disease, and QT-prolongation is needed (Savides and Outhoff 2024).
● Variations in the content of psilocybin in mushrooms and the illicit nature of LSD further complicate the development of consistent dosing (Syed et al , n d )
7. Limited Understanding of Risk Factors:
● There is a need to identify factors that predict a negative response to psychedelics, particularly for patients with low-grade psychotic symptoms It is essential to carefully screen patients for vulnerabilities before recommending psychedelic experiences (Barber and Dike 2023)
● More research is needed on the potential risks of psychosis and schizophrenia spectrum disorder associated with hallucinogen use. There is a need to understand if psychedelics may provoke a psychosis or manic episode (Palitsky et al., n.d.).
● There is an uncertainty about how much harm psychedelics can cause at different doses While they are generally considered safe at low doses and not addictive, more research is needed to understand the mechanism of action and their metabolic pathways (Henríquez-Hernández et al 2023)
8. Role of Psychotherapy:
● The interplay between psychedelics and psychotherapy remains unclear More research is needed to differentiate the effects of the drug from the therapeutic process, determine the essential elements of effective psychedelic-assisted therapy, and inform best
practices (Armstrong and Davis 2024; Kishon et al 2024; Campo and Yali 2024; Cavarra et al. 2022; Devenot, Conner, and Doyle 2022; Fonzo, Nemeroff, and Kalin 2025; 2025; Neitzke-Spruill et al. 2024).
9 Crisis Interventions:
● There is a lack of research on effective crisis interventions for managing challenging experiences during psychedelic sessions, hindering the development of comprehensive safety protocols (Barber, Gardner, and Carter 2024; Gorman et al 2021; Marrocu et al , n.d.). It is necessary to investigate effective crisis intervention strategies for managing challenging experiences during psychedelic sessions, including protocols and training for therapists in harm reduction practices (Evans et al 2023)
The above-described gaps significantly limit the effectiveness of harm reduction measures Without a comprehensive understanding of risks, safety protocols for use of these substances are difficult to formulate (Rossi et al 2022) Harm reduction efforts depend on knowing who is most at risk and how to mitigate those risks, but current data does not provide these answers (Piercey et al. 2024). In addition, without a clear understanding of what constitutes a “safe” psychedelic experience, it's difficult to create meaningful guidelines for those who use psychedelics outside of a controlled setting
Substance-Specific Research Gaps
Psilocybin
1 Dose-response studies: It is essential to conduct studies that explore a range of doses and dosing schedules to identify optimal regimens that minimize adverse outcomes (Savides & Outhoff, 2024).
2 Clinical populations: Further research should investigate the safety and tolerability of psilocybin microdosing in clinical populations, such as those with mental health disorders or chronic conditions, to determine how these individuals are impacted (Savides & Outhoff, 2024)
3. Cardiac safety: Given the potential for psilocybin to impact cardiac function, future research should prioritize investigating the effects of microdosing on cardiovascular health This includes exploring risks related to heart rate, blood pressure, and potential cardiac conditions (Savides & Outhoff, 2024).
4 Polydrug use: Further studies are needed to investigate the effects of combining psilocybin microdosing with other substances, especially other psychiatric medications. Understanding drug-drug interactions is crucial for mitigating risks like serotonin syndrome and ensuring safer use (Savides & Outhoff, 2024)
LSD
1 Long-term effects of microdosing: Further research is needed on these, especially concerning cardiovascular health (Bornemann, 2020). It is also essential to develop a standardized questionnaire to better detect and understand the effects of microdosing (Murphy, Muthukumaraswamy, and de Wit, 2024). Clinical trials should explore a broader range of doses and schedules to compare varying effects
2 Harm reduction practices: Test dosing and the use of home testing kits to confirm the presence of LSD, should be encouraged to minimize risks (Lea et al., 2020; Baxter et al., 2024)
DMT
1 Limited data: There is a lack of comprehensive research on the phenomenology of DMT use (Dourron et al 2023) More research into the subjective effects of DMT is needed (Rucker et al 2023)
2. Mechanism of action: Further pre-clinical research is needed to understand how DMT affects 5-HT1A receptors and the brain (Dourron et al. 2023). It is unclear whether DMT is a full or partial agonist at the 5-HT1A receptors (Dourron et al. 2023).
3 Dose response data: There is still a lack of dose response data for therapeutic applications of DMT (Pantoni et al 2022)
Ibogaine
1 Exploring alternative therapeutic compounds derived from iboga, such as noribogaine, 18-MC, and tabernanthalog, which may offer a more favorable safety profile, could be valuable (Cherian et al. 2024; Gomez-Escolar et al. 2024). These synthetic analogs could potentially address the challenges of inconsistent potency and contamination associated with natural ibogaine preparations
Ketamine
1. Further research on the safety of long-term ketamine use on various systems including the cardiovascular system, cognition, genitourinary system, and liver is needed (Riva-Posse et al. 2018).
References
2023 National Survey on Drug Use and Health (NSDUH) Releases. (n.d.). Retrieved January 27, 2025, from https://www.samhsa.gov/data/release/2023-national-survey-drug-use-and-health-nsduh-release s#detailed-tables
A retrospective analysis of the “Neverending Trip” after administration of a potent full agonist of 5-HT2A receptor – 25I-NBOMe. (n.d.). ResearchGate. Retrieved January 14, 2025, from https://www.researchgate.net/publication/357477776 A retrospective analysis of the Nevere nding Trip after administration of a potent full agonist of 5-HT2A receptor - 25I-NBOMe
Aakerøy, R., Brede, W. R., Stølen, S. B., Krabseth, H.-M., Michelsen, L. S., Andreassen, T. N., Ader, T., Frost, J., Slettom, G., Steihaug, O. M., & Slørdal, L. (2021). Severe Neurological Sequelae after a Recreational Dose of LSD Journal of Analytical Toxicology, 45(7), e1–e3 https://doi org/10 1093/jat/bkaa145
Aaronson, S T, Van Der Vaart, A , Miller, T, LaPratt, J , Swartz, K , Shoultz, A , Lauterbach, M , Suppes, T, & Sackeim, H A (2025) Single-Dose Psilocybin for Depression With Severe Treatment Resistance: An Open-Label Trial American Journal of Psychiatry, 182(1), 104–113
https://doi org/10 1176/appi ajp 20231063
Abdullah, M F I L , Singh, D , & Kasinather, B V (2018) CASE REPORT OF RECREATIONAL LYSERGIC-ACID-DIETHYLAMIDE (LSD) USE IN MALAYSIA ASEAN
Journal of Psychiatry, 19(1), 1–1.
Ables, J L , Israel, L , Wood, O , Govindarajulu, U , Fremont, R T, Banerjee, R , Liu, H , Cohen, J., Wang, P., Kumar, K., Lu, G., DeVita, R. J., Garcia-Ocaña, A., Murrough, J. W., & Stewart, A. F. (2024). A Phase 1 single ascending dose study of pure oral harmine in healthy volunteers Journal of Psychopharmacology (Oxford, England), 38(10), 911–923
https://doi org/10 1177/02698811241273772
Abraham, H. D., & Aldridge, A. M. (1993). Adverse consequences of lysergic acid diethylamide. Addiction, 88(10), 1327–1334 https://doi org/10 1111/j 1360-0443 1993 tb02018 x
Abraham, H. D., & Duffy, F. H. (1996). Stable quantitative EEG difference in post-LSD visual disorder by split-half analysis: Evidence for disinhibition Psychiatry Research, 67(3), 173–187 https://doi org/10 1016/0925-4927(96)02833-8
Abrams, S K , Rabinovitch, B S , Zafar, R , Aziz, A S , Cherup, N P, McMillan, D W, Nielson, J L , & Lewis, E C (2023) Persons With Spinal Cord Injury Report Peripherally Dominant Serotonin-Like Syndrome After Use of Serotonergic Psychedelics Neurotrauma Reports, 4(1), 543–550 https://doi org/10 1089/neur2023 0022
Adams, J H (2023a, September 22) Psychedelics and the ethics of suggestibility Ecstatic Integration https://wwwecstaticintegration org/p/psychedelics-and-the-ethics-of-suggestibility
Adams, J H (2023b, September 29) The power of psychedelic-assisted suggestion: Part two of our analysis of the ethics of suggestibility Ecstatic Integration https://www.ecstaticintegration.org/p/the-ethics-of-psychedelic-suggestibility
Aday, J S , Bloesch, E K , & Davoli, C C (2020) Can Psychedelic Drugs Attenuate Age-Related Changes in Cognition and Affect? Journal of Cognitive Enhancement, 4(2), 219–227. https://doi.org/10.1007/s41465-019-00151-6
Aday, J. S., Boehnke, K. F., Herberholz, M., & Kruger, D. J. (2024). Attitudes of psychedelic users regarding cost of treatment and non-hallucinogenic alternatives. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00354
Aday, J. S., Davis, A. K., Mitzkovitz, C. M., Bloesch, E. K., & Davoli, C. C. (2021). Predicting Reactions to Psychedelic Drugs: A Systematic Review of States and Traits Related to Acute Drug Effects ACS Pharmacology & Translational Science, 4(2), 424–435 https://doi org/10 1021/acsptsci 1c00014
Aday, J S , Heifets, B D , Pratscher, S D , Bradley, E , Rosen, R , & Woolley, J D (2022) Great Expectations: Recommendations for improving the methodological rigor of psychedelic clinical trials Psychopharmacology, 239(6), 1989–2010 https://doi org/10 1007/s00213-022-06123-7
Aday, J S , Horton, D , Fernandes-Osterhold, G , O’Donovan, A , Bradley, E R , Rosen, R C , & Woolley, J D (2024) Psychedelic-assisted psychotherapy: Where is the psychotherapy research? Psychopharmacology, 241(8), 1517–1526. https://doi.org/10.1007/s00213-024-06620-x
Aday, J. S., Mitzkovitz, C. M., Bloesch, E. K., Davoli, C. C., & Davis, A. K. (2020). Long-term effects of psychedelic drugs: A systematic review. Neuroscience & Biobehavioral Reviews, 113, 179–189. https://doi.org/10.1016/j.neubiorev.2020.03.017
Aday, J. S., Wood, J. R., Bloesch, E. K., & Davoli, C. C. (2021). Psychedelic drugs and perception: A narrative review of the first era of research. Reviews in the Neurosciences, 32(5), 559–571 https://doi org/10 1515/revneuro-2020-0094
Aixalà, M., Dos Santos, R. G., Hallak, J. E. C., & Bouso, J. C. (2018). Psychedelics and Personality ACS Chemical Neuroscience, 9(10), 2304–2306 https://doi org/10 1021/acschemneuro 8b00237
Aixalá, M., Ona, G., Parés, Ò., & Bouso, J. C. (2020). Patterns of use, desired effects, and mental health status of a sample of natural psychoactive drug users Drugs: Education, Prevention and Policy, 27(3), 191–198 https://doi org/10 1080/09687637 2019 1611739
Ajantaival, T J (2014) Psychedelics and indicators of mental distress in adults: National Survey on Drug Use and Health 2008–2014
Alcántara, A G (1998) Is there a role for the alpha2 antagonism in the exacerbation of hallucinogen-persisting perception disorder with risperidone? Journal of Clinical Psychopharmacology, 18(6), 487–488 https://doi org/10 1097/00004714-199812000-00016
Aleman, J , Crul, M , Voort, P H J van der, & Franssen, E J F (2012) Anticholinergic toxicity after the ingestion of serotonergic “magic mushrooms.” Netherlands Journal of Critical Care, 16(3), 93–96.
Al-Imam, A. (2017). The Preferred Terminology Implemented by Psychedelic Users Existing on Online Platforms: A Cross-sectional Analysis. Global Journal of Health Science, 9(11), 140. https://doi.org/10.5539/gjhs.v9n11p140
Álvarez, C. S., Mazarrasa, J., Faura, R., Bouso, J. C., Domsac, I., Russo, S., & Verdaguer, Á. (n.d.). International Center for Ethnobotanical Education, Research and Service (ICEERS).
Alyahya, N. M., & Al Saleem, E. A. (2024). Therapeutic Use of Psychedelics for Mental Disorders: A Systematized Review. Journal of Nature and Science of Medicine. https://doi org/10 4103/jnsm jnsm 76 24
Ambrose, J., & Zabinski, J. (2023). Psychedelic Renaissance: Clinical Health Justice, Patient Safety, and Equity Need to Be Put First Psychiatric News, 58(03) https://doi org/10 1176/appi pn 2023 03 3 43
Amsterdam, J. van, Opperhuizen, A., & Brink, W. van den. (2011). Harm potential of magic mushroom use: A review Regulatory Toxicology and Pharmacology, 59(3), 423–429 https://doi org/10 1016/j yrtph 2011 01 006
Analysis of Risk Reduction Among Organized Groups That Promote Marijuana and Psychedelic Drugs | Office of Justice Programs (n d ) Retrieved January 4, 2025, from https://wwwojp gov/ncjrs/virtual-library/abstracts/analysis-risk-reduction-among-organized-group s-promote-marijuana
Andersen, K A A , Carhart‐Harris, R , Nutt, D J , & Erritzoe, D (2021) Therapeutic effects of classic serotonergic psychedelics: A systematic review of modern‐era clinical studies Acta Psychiatrica Scandinavica, 143(2), 101–118. https://doi.org/10.1111/acps.13249
Anderson, L , Lake, H , & Walterfang, M (2018) The trip of a lifetime: Hallucinogen persisting perceptual disorder. Australasian Psychiatry, 26(1), 11–12.
https://doi.org/10.1177/1039856217726694
Anderson, T., Petranker, R., Christopher, A., Rosenbaum, D., Weissman, C., Dinh-Williams, L.-A., Hui, K., & Hapke, E. (2019). Psychedelic microdosing benefits and challenges: An empirical codebook. Harm Reduction Journal, 16(1), 43.
https://doi org/10 1186/s12954-019-0308-4
Anderson, T., Petranker, R., Rosenbaum, D., Weissman, C. R., Dinh-Williams, L.-A., Hui, K., Hapke, E , & Farb, N A S (2019) Microdosing psychedelics: Personality, mental health, and creativity differences in microdosers Psychopharmacology, 236(2), 731–740
https://doi org/10 1007/s00213-018-5106-2
Argento, E , Petker, T, Vig, J , Robertson, C , Jaeger, A , Necyk, C , Thielking, P, & Walsh, Z (2024). “This is you teaching you:” Exploring providers’ perspectives on experiential learning and enhancing patient safety and outcomes in ketamine-assisted therapy. PLOS ONE, 19(8), e0306381 https://doi org/10 1371/journal pone 0306381
Argyri, E. K., Evans, J., Luke, D., Michael, P., Michelle, K., Rohani-Shukla, C., Suseelan, S., Prideaux, E., McAlpine, R., Murphy-Beiner, A., & Robinson, O. (2024). Navigating Groundlessness: An interview study on dealing with ontological shock and existential distress following psychedelic experiences (SSRN Scholarly Paper No 4817368) Social Science Research Network https://doi org/10 2139/ssrn 4817368
Arikci, D , Holze, F, Mueller, L , Vizeli, P, Rudin, D , Luethi, D , & Liechti, M E (2025)
Absolute Oral Bioavailability and Bioequivalence of LSD Base and Tartrate in a Double‐Blind, Placebo‐Controlled, Crossover Study Clinical Pharmacology & Therapeutics https://doi.org/10.1002/cpt.3726
Armstrong, S B , & Davis, A K (2024) Psychedelic research at a crossroads Science, 385(6715), 1255–1255. https://doi.org/10.1126/science.adt1024
Ashraf, N (2024) IS PSYCHEDELIC TREATMENT OF MENTAL HEALTH DISORDERS READY FOR PRIME TIME? Journal of Pakistan Psychiatric Society, 21(02). https://doi.org/10.63050/jpps.21.02.935
Asselborn, G., Wennig, R., & Yegles, M. (n.d.). Tragic flying attempt under the influence of “magic mushrooms.”
Atila, C., Straumann, I., Vizeli, P., Beck, J., Monnerat, S., Holze, F., Liechti, M. E., & Christ-Crain, M. (2024a). Oxytocin and the Role of Fluid Restriction in MDMA-Induced Hyponatremia: A Secondary Analysis of 4 Randomized Clinical Trials. JAMA Network Open, 7(11), e2445278 https://doi org/10 1001/jamanetworkopen 2024 45278
Atila, C., Straumann, I., Vizeli, P., Beck, J., Monnerat, S., Holze, F., Liechti, M. E., & Christ-Crain, M (2024b) Oxytocin and the Role of Fluid Restriction in MDMA-Induced Hyponatremia: A Secondary Analysis of 4 Randomized Clinical Trials JAMA Network Open, 7(11), e2445278 https://doi org/10 1001/jamanetworkopen 2024 45278
Bae, S , Vaysblat, M , Bae, E , Dejanovic, I , & Pierce, M (2023) Cardiac Arrest Associated With Psilocybin Use and Hereditary Hemochromatosis Cureus https://doi org/10 7759/cureus 38669
Bagdasarian, F A , Hansen, H D , Chen, J , Yoo, C -H , Placzek, M S , Hooker, J M , & Wey, H -Y (2024) Acute Effects of Hallucinogens on Functional Connectivity: Psilocybin and Salvinorin-A. ACS Chemical Neuroscience, 15(14), 2654–2661. https://doi.org/10.1021/acschemneuro.4c00245
Baggott, M J (n d ) Other Times I Can Barely See: The Effects of Hallucinogens on Vision and Attention.
Baggott, M J , Coyle, J R , Erowid, E , Erowid, F, & Robertson, L C (2011a) Abnormal visual experiences in individuals with histories of hallucinogen use: A Web-based questionnaire. Drug and Alcohol Dependence, 114(1), 61–67. https://doi.org/10.1016/j.drugalcdep.2010.09.006
Baggott, M. J., Coyle, J. R., Erowid, E., Erowid, F., & Robertson, L. C. (2011b). Abnormal visual experiences in individuals with histories of hallucinogen use: A Web-based questionnaire. Drug and Alcohol Dependence, 114(1), 61–67. https://doi.org/10.1016/j.drugalcdep.2010.09.006
Baggott, M. J., Garrison, K. J., Coyle, J. R., Galloway, G. P., Barnes, A. J., Huestis, M. A., & Mendelson, J. E. (2019). Effects of the Psychedelic Amphetamine MDA (3,4-Methylenedioxyamphetamine) in Healthy Volunteers Journal of Psychoactive Drugs, 51(2), 108–117 https://doi org/10 1080/02791072 2019 1593560
Bakshi, B , Yerraguntla, S , Armon, C , Barkhaus, P, Bertorini, T, Bowser, R , Breevoort, S , Bromberg, M , Brown, A , Carter, G T, Chang, V, Crayle, J , Fullam, T, Greene, M , Heiman-Patterson, T, Jackson, C , Jhooty, S , Mallon, E , Cadavid, J M , Bedlack, R (n d )
ALSUntangled #77: Psilocybin Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 0(0), 1–4. https://doi.org/10.1080/21678421.2024.2441274
Bălăeţ, M (2022) Psychedelic Cognition The Unreached Frontier of Psychedelic Science Frontiers in Neuroscience, 16, 832375. https://doi.org/10.3389/fnins.2022.832375
Baldo, B A (2024) The entactogen 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) as a treatment aid in psychotherapy and its safety concerns Archives of Toxicology, 98(8), 2409–2427. https://doi.org/10.1007/s00204-024-03765-8
Ballard, E D , Farmer, C A , Gerner, J , Bloomfield-Clagett, B , Park, L T, & Zarate, C A (2022). Prospective association of psychological pain and hopelessness with suicidal thoughts. Journal of Affective Disorders, 308, 243–248. https://doi.org/10.1016/j.jad.2022.04.033
Banta-Green, C., Goldbaum, G., Kingston, S., Golden, M., Harruff, R., & Logan, B. K. (2005). Epidemiology of MDMA and Associated Club Drugs in the Seattle Area. Substance Use & Misuse, 40(9–10), 1295–1315. https://doi.org/10.1081/JA-200066793
Barber, G., Nemeroff, C. B., & Siegel, S. (2022). A Case of Prolonged Mania, Psychosis, and Severe Depression After Psilocybin Use: Implications of Increased Psychedelic Drug
Availability American Journal of Psychiatry, 179(12), 892–896
https://doi org/10 1176/appi ajp 22010073
Barber, G S , & Dike, C C (2023) Ethical and Practical Considerations for the Use of Psychedelics in Psychiatry Psychiatric Services (Washington, D C ), 74(8), 838–846
https://doi org/10 1176/appi ps 20220525
Barber, M , Gardner, J , & Carter, A (2024) History, Hype, and Responsible Psychedelic Medicine: A Qualitative Study of Psychedelic Researchers. Journal of Bioethical Inquiry. https://doi.org/10.1007/s11673-024-10386-4
Barker, S. A. (2022). Administration of N,N-dimethyltryptamine (DMT) in psychedelic therapeutics and research and the study of endogenous DMT. Psychopharmacology, 239(6), 1749–1763. https://doi.org/10.1007/s00213-022-06065-0
Barnett, B. S. (2022). Deepening our understanding of psychedelics by expanding psychedelic data collection in the United States National Survey on Drug Use and Health. Journal of Psychopharmacology, 36(10), 1097–1099 https://doi org/10 1177/02698811221123051
Barnett, B. S., Anand, A., Dewey, E. N., Smith, D., Nayak, S. M., Bruckman, D., & Weleff, J. (2024) Perceived Risk of Trying Lysergic Acid Diethylamide in the United States from 2015 to 2019: Are Americans Assessing Lysergic Acid Diethylamide’s Risk Profile More Favorably? Psychedelic Medicine, 2(2), 74–86 https://doi org/10 1089/psymed 2023 0027
Barnett, B S , & Greer, G R (2021) Psychedelic Psychiatry and the Consult-Liaison Psychiatrist: A Primer Journal of the Academy of Consultation-Liaison Psychiatry, 62(4), 460–471 https://doi org/10 1016/j jaclp 2020 12 011
Barnett, B S , Ziegler, K , Doblin, R , & Carlo, A D (2022) Is psychedelic use associated with cancer?: Interrogating a half-century-old claim using contemporary population-level data Journal of Psychopharmacology (Oxford, England), 36(10), 1118–1128. https://doi.org/10.1177/02698811221117536
Barrett, F. S., Bradstreet, M. P., Leoutsakos, J.-M. S., Johnson, M. W., & Griffiths, R. R. (2016). The Challenging Experience Questionnaire: Characterization of challenging experiences with psilocybin mushrooms. Journal of Psychopharmacology, 30(12), 1279–1295. https://doi org/10 1177/0269881116678781
Barrett, F. S., Carbonaro, T. M., Hurwitz, E., Johnson, M. W., & Griffiths, R. R. (2018). Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: Effects on cognition Psychopharmacology, 235(10), 2915–2927
https://doi org/10 1007/s00213-018-4981-x
Barrett, F S , Doss, M K , Sepeda, N D , Pekar, J J , & Griffiths, R R (2020) Emotions and brain function are altered up to one month after a single high dose of psilocybin Scientific Reports, 10(1), 2214 https://doi org/10 1038/s41598-020-59282-y
Barrett, F S , Johnson, M W, & Griffiths, R R (2017) Neuroticism is associated with challenging experiences with psilocybin mushrooms Personality and Individual Differences, 117, 155–160. https://doi.org/10.1016/j.paid.2017.06.004
Barrios, K P, Connolly, D J , Ferris, J A , Maier, L J , Barratt, M J , Winstock, A R , Puljević, C , & Gilchrist, G (2024) Ketamine use in a large global sample: Characteristics, patterns of
use and emergency medical treatment Journal of Psychopharmacology, 02698811241273850
https://doi.org/10.1177/02698811241273850
Basedow, L A , & Kuitunen-Paul, S (2022) Motives for the use of serotonergic psychedelics: A systematic review. Drug and Alcohol Review, 41(6), 1391–1403.
https://doi.org/10.1111/dar.13480
Basedow, L. A., Majić, T., Hafiz, N. J., Algharably, E. A. E., Kreutz, R., & Riemer, T. G. (2024). Cognitive functioning associated with acute and subacute effects of classic psychedelics and MDMA - a systematic review and meta-analysis. Scientific Reports, 14(1), 14782.
https://doi org/10 1038/s41598-024-65391-9
Bathje, G. J., Majeski, E., & Kudowor, M. (2022). Psychedelic integration: An analysis of the concept and its practice Frontiers in Psychology, 13, 824077
https://doi org/10 3389/fpsyg 2022 824077
Baumann, S , Carhart-Harris, R , Nutt, D , Erritzoe, D , & Szigeti, B (2022) Evidence for tolerance in psychedelic microdosing from the self-blinding microdose trial PsyArXiv https://doi org/10 31234/osf io/s4qhf
Baumeister, D , Tojo, L M , & Tracy, D K (2015) Legal highs: Staying on top of the flood of novel psychoactive substances Therapeutic Advances in Psychopharmacology, 5(2), 97–132
https://doi org/10 1177/2045125314559539
Baxter, L , Puljević, C , Piatkowski, T, Ferris, J , Davies, E L , Barratt, M J , & Winstock, A (2024a) Tripping into the unknown: Exploring the experiences of first-time LSD users through global drug survey insights. Journal of Psychopharmacology, 38(8), 735–748. https://doi.org/10.1177/02698811241254837
Baxter, L , Puljević, C , Piatkowski, T, Ferris, J , Davies, E L , Barratt, M J , & Winstock, A (2024b). Tripping into the unknown: Exploring the experiences of first-time LSD users through global drug survey insights. Journal of Psychopharmacology, 38(8), 735–748. https://doi org/10 1177/02698811241254837
Becker, A. M., Klaiber, A., Holze, F., Istampoulouoglou, I., Duthaler, U., Varghese, N., Eckert, A., & Liechti, M. E. (2023). Ketanserin Reverses the Acute Response to LSD in a Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Participants The International Journal of Neuropsychopharmacology, 26(2), 97–106 https://doi org/10 1093/ijnp/pyac075
Bender, D , & Hellerstein, D J (2022) Assessing the risk–benefit profile of classical psychedelics: A clinical review of second-wave psychedelic research Psychopharmacology, 239(6), 1907–1932 https://doi org/10 1007/s00213-021-06049-6
Bennett, J N , Blough, M D , Mitchell, I , Galloway, L , & Bains, R (2023) A Phase I trial to inform clinical protocols for the safe administration of psilocybin-assisted psychotherapy Psychiatry and Clinical Psychology https://doi org/10 1101/2023 04 12 23288325
Bienemann, B , Ruschel, N S , Campos, M L , Negreiros, M A , & Mograbi, D C (2020) Self-reported negative outcomes of psilocybin users: A quantitative textual analysis. PLOS ONE, 15(2), e0229067. https://doi.org/10.1371/journal.pone.0229067
Black, J. C., Monte, A. A., Dasgupta, N., Jewell, J. S., Rockhill, K. M., Olson, R. A., & Dart, R. C. (2024). Optimizing real-world benefit and risk of new psychedelic medications: The need for innovative postmarket surveillance. Nature Mental Health, 2(5), 469–477. https://doi org/10 1038/s44220-024-00233-1
Blaho, K., Merigian, K., Winbery, S., Geraci, S. A., & Smartt, C. (1997). Clinical pharmacology of lysergic acid diethylamide: Case reports and review of the treatment of intoxication American Journal of Therapeutics, 4(5–6), 211–221 https://doi org/10 1097/00045391-199705000-00008
Blest-Hopley, G , Amit, B H , O’Neill, A , & Ruffell, S G D (2023) Editorial: Appropriateness and safety of using cannabinoid and psychedelic medicines as treatments for psychiatric disorders Frontiers in Psychiatry, 14, 1191970 https://doi org/10 3389/fpsyt 2023 1191970
Blond, B N , & Schindler, E A D (2023) Case report: Psychedelic-induced seizures captured by intracranial electrocorticography Frontiers in Neurology, 14, 1214969 https://doi org/10 3389/fneur2023 1214969
Bodnár, K J , & Kakuk, P (2019) Research ethics aspects of experimentation with LSD on human subjects: A historical and ethical review Medicine, Health Care and Philosophy, 22(2), 327–337. https://doi.org/10.1007/s11019-018-9871-9
Bogenschutz, M P, Forcehimes, A A , Pommy, J A , Wilcox, C E , Barbosa, P, & Strassman, R J (2015) Psilocybin-assisted treatment for alcohol dependence: A proof-of-concept study Journal of Psychopharmacology, 29(3), 289–299. https://doi.org/10.1177/0269881114565144
Bøhling, F (2017) Psychedelic pleasures: An affective understanding of the joys of tripping The International Journal on Drug Policy, 49, 133–143. https://doi.org/10.1016/j.drugpo.2017.07.017
Bonson, K R (2018) Regulation of human research with LSD in the United States (1949-1987). Psychopharmacology, 235(2), 591–604. https://doi.org/10.1007/s00213-017-4777-4
Bonson, K. R., Buckholtz, J. W., & Murphy, D. L. (1996). Chronic administration of serotonergic antidepressants attenuates the subjective effects of LSD in humans. Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 14(6), 425–436 https://doi org/10 1016/0893-133X(95)00145-4
Bormann, N. L., Weber, A. N., Miskle, B., Woodson-DeFauw, N., Arndt, S., & Lynch, A. C. (2023) Perceived risk of LSD varies with age and race: Evidence from 2019 United States cross-sectional data Social Psychiatry and Psychiatric Epidemiology, 58(10), 1503–1508 https://doi org/10 1007/s00127-023-02448-6
Bornemann, J (2020) The Viability of Microdosing Psychedelics as a Strategy to Enhance Cognition and Well-being An Early Review. Journal of Psychoactive Drugs, 52(4), 300–308. https://doi.org/10.1080/02791072.2020.1761573
Bouchet, L., Sager, Z., Yrondi, A., Nigam, K. B., Anderson, B. T., Ross, S., Petridis, P. D., & Beaussant, Y. (2024). Older adults in psychedelic-assisted therapy trials: A systematic review. Journal of Psychopharmacology, 38(1), 33–48 https://doi org/10 1177/02698811231215420
Bouso, J. C., Andión, Ó., Sarris, J. J., Scheidegger, M., Tófoli, L. F., Opaleye, E. S., Schubert, V., & Perkins, D. (2022). Adverse effects of ayahuasca: Results from the Global Ayahuasca Survey PLOS Global Public Health, 2(11), e0000438
https://doi org/10 1371/journal pgph 0000438
Braun, V, & Clarke, V (2006) Using thematic analysis in psychology Qualitative Research in Psychology, 3(2), 77–101 https://doi org/10 1191/1478088706qp063oa
Breeksema, J J , Kuin, B W, Kamphuis, J , Van Den Brink, W, Vermetten, E , & Schoevers, R A (2022) Adverse events in clinical treatments with serotonergic psychedelics and MDMA: A mixed-methods systematic review Journal of Psychopharmacology, 36(10), 1100–1117 https://doi org/10 1177/02698811221116926
Breeksema, J J , Niemeijer, A , Krediet, E , Karsten, T, Kamphuis, J , Vermetten, E , Van Den Brink, W, & Schoevers, R (2024) Patient perspectives and experiences with psilocybin treatment for treatment-resistant depression: A qualitative study. Scientific Reports, 14(1), 2929. https://doi.org/10.1038/s41598-024-53188-9
Breeksema, J. J., Niemeijer, A., Kuin, B., Veraart, J., Kamphuis, J., Schimmel, N., van den Brink, W., Vermetten, E., & Schoevers, R. (2022). Holding on or letting go? Patient experiences of control, context, and care in oral esketamine treatment for treatment-resistant depression: A qualitative study Frontiers in Psychiatry, 13, 948115 https://doi org/10 3389/fpsyt 2022 948115
Bremler, R., Katati, N., Shergill, P., Erritzoe, D., & Carhart-Harris, R. (2023a). Focusing on the negative: Cases of long-term negative psychological responses to psychedelics PsyArXiv https://doi org/10 31234/osf io/yzmcj
Bremler, R., Katati, N., Shergill, P., Erritzoe, D., & Carhart-Harris, R. L. (2023b). Case analysis of long-term negative psychological responses to psychedelics Scientific Reports, 13(1), 15998 https://doi org/10 1038/s41598-023-41145-x
Brodrick, J , & Mitchell, B G (2016) Hallucinogen Persisting Perception Disorder and Risk of Suicide Journal of Pharmacy Practice, 29(4), 431–434
https://doi org/10 1177/0897190014566314
Bruce, L (2025) Psychedelics in a Deregulated Policy Climate: What Might 2025 Bring? The American Journal of Bioethics
https://wwwtandfonline com/doi/abs/10 1080/15265161 2024 2433420
Butler, M , Seynaeve, M , Nicholson, T R , Pick, S , Kanaan, R A A , Lees, A , Young, A H , & Rucker, J. (n.d.). Psychedelic treatment of functional neurological disorder: A systematic review. Therapeutic Advances in Psychopharmacology.
Byrne, K. J., Lindsay, S., Baker, N., Schmutz, C., & Lewis, B. (2023). In naturalistic psychedelic use, group use is common and acceptable. Journal of Psychedelic Studies, 7(2), 100–113. https://doi org/10 1556/2054 2023 00261
Calder, A. E., & Hasler, G. (2024a). Validation of the Swiss Psychedelic Side Effects Inventory: Standardized assessment of adverse effects in studies of psychedelics and MDMA. Journal of Affective Disorders, 365, 258–264 https://doi org/10 1016/j jad 2024 08 091
Calder, A. E., & Hasler, G. (2024b). Validation of the Swiss Psychedelic Side Effects Inventory: Standardized assessment of adverse effects in studies of psychedelics and MDMA Journal of Affective Disorders, 365, 258–264 https://doi org/10 1016/j jad 2024 08 091
Calder, A E , Rausch, B , Liechti, M E , Holze, F, & Hasler, G (2024) Naturalistic psychedelic therapy: The role of relaxation and subjective drug effects in antidepressant response Journal of Psychopharmacology, 38(10), 873–886 https://doi org/10 1177/02698811241278873
Calder, A , & Hasler, G (2023) Extrapharmacological Safety Topics in Psychedelic-Assisted Psychotherapy JAMA Psychiatry, 80(8), 761 https://doi org/10 1001/jamapsychiatry2023 1031
Calina, D , Carvalho, F, & Oana Docea, A (2021) Chapter 43 Toxicity of psychedelic drugs In A M Tsatsakis (Ed ), Toxicological Risk Assessment and Multi-System Health Impacts from Exposure (pp 545–556) Academic Press https://doi org/10 1016/B978-0-323-85215-9 00022-2
Callon, C , Williams, M , & Lafrance, A (2021) “Meeting the Medicine Halfway”: Ayahuasca Ceremony Leaders’ Perspectives on Preparation and Integration Practices for Participants Journal of Humanistic Psychology, 00221678211043300 https://doi.org/10.1177/00221678211043300
Cameron, L P (2021) Asking questions of psychedelic microdosing eLife, 10, e66920 https://doi.org/10.7554/eLife.66920
Cameron, L P, Nazarian, A , & Olson, D E (2020) Psychedelic Microdosing: Prevalence and Subjective Effects. Journal of Psychoactive Drugs, 52(2), 113–122. https://doi.org/10.1080/02791072.2020.1718250
Campo, W M , & Yali, A M (2024) Psychedelic use and psychological flexibility: The role of meaningful intention and decentering. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00350
Canady, V. A. (2023a). FDA issues first draft guidance on psychedelic research. Mental Health Weekly, 33(26), 3–5. https://doi.org/10.1002/mhw.33697
Canady, V A (2023b) Report finds psychedelic helpline may avert harmful outcomes Mental Health Weekly, 33(25), 5–6. https://doi.org/10.1002/mhw.33691
Carbonaro, T M , Bradstreet, M P, Barrett, F S , MacLean, K A , Jesse, R , Johnson, M W, & Griffiths, R. R. (2016). Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences. Journal of Psychopharmacology, 30(12), 1268–1278 https://doi org/10 1177/0269881116662634
Carbonaro, T. M., Johnson, M. W., Hurwitz, E., & Griffiths, R. R. (2018). Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: Similarities and differences in subjective experiences Psychopharmacology, 235(2), 521–534
https://doi org/10 1007/s00213-017-4769-4
Carhart-Harris, R , Giribaldi, B , Watts, R , Baker-Jones, M , Murphy-Beiner, A , Murphy, R , Martell, J , Blemings, A , Erritzoe, D , & Nutt, D J (2021) Trial of Psilocybin versus Escitalopram for Depression New England Journal of Medicine, 384(15), 1402–1411
https://doi org/10 1056/NEJMoa2032994
Carhart-Harris, R L , Bolstridge, M , Day, C M J , Rucker, J , Watts, R , Erritzoe, D E , Kaelen, M , Giribaldi, B , Bloomfield, M , Pilling, S , Rickard, J A , Forbes, B , Feilding, A , Taylor, D , Curran, H. V., & Nutt, D. J. (2018). Psilocybin with psychological support for treatment-resistant depression: Six-month follow-up. Psychopharmacology, 235(2), 399–408.
https://doi org/10 1007/s00213-017-4771-x
Carhart-Harris, R. L., & Goodwin, G. M. (2017). The Therapeutic Potential of Psychedelic Drugs: Past, Present, and Future. Neuropsychopharmacology, 42(11), 2105–2113. https://doi org/10 1038/npp 2017 84
Carhart-Harris, R. L., & Nutt, D. J. (2010). User perceptions of the benefits and harms of hallucinogenic drug use: A web-based questionnaire study Journal of Substance Use, 15(4), 283–300 https://doi org/10 3109/14659890903271624
Carhart-Harris, R L , & Nutt, D J (2013) Experienced drug users assess the relative harms and benefits of drugs: A web-based survey Journal of Psychoactive Drugs, 45(4), 322–328 https://doi org/10 1080/02791072 2013 825034
Carhart-Harris, R L , Roseman, L , Haijen, E , Erritzoe, D , Watts, R , Branchi, I , & Kaelen, M (2018a) Psychedelics and the essential importance of context Journal of Psychopharmacology (Oxford, England), 32(7), 725–731 https://doi org/10 1177/0269881118754710
Carhart-Harris, R L , Roseman, L , Haijen, E , Erritzoe, D , Watts, R , Branchi, I , & Kaelen, M (2018b) Psychedelics and the essential importance of context Journal of Psychopharmacology, 32(7), 725–731. https://doi.org/10.1177/0269881118754710
Carhart-Harris, R L , Williams, T M , Sessa, B , Tyacke, R J , Rich, A S , Feilding, A , & Nutt, D J (2011) The administration of psilocybin to healthy, hallucinogen-experienced volunteers in
a mock-functional magnetic resonance imaging environment: A preliminary investigation of tolerability. Journal of Psychopharmacology (Oxford, England), 25(11), 1562–1567. https://doi.org/10.1177/0269881110367445
Carvalho, M. C., de Sousa, M. P., Frango, P., Dias, P., Carvalho, J., Rodrigues, M., & Rodrigues, T. (2014). Crisis intervention related to the use of psychoactive substances in recreational settings Evaluating the Kosmicare Project at Boom Festival Current Drug Abuse Reviews, 7(2), 81–100 https://doi org/10 2174/1874473708666150107115515
Case analysis of long-term negative psychological responses to psychedelics | Scientific Reports (n d ) Retrieved January 12, 2025, from https://wwwnature com/articles/s41598-023-41145-x
Caudevilla-Gálligo, F, Riba, J , Ventura, M , González, D , Farré, M , Barbanoj, M J , & Bouso, J C (2012) 4-Bromo-2,5-dimethoxyphenethylamine (2C-B): Presence in the recreational drug market in Spain, pattern of use and subjective effects Journal of Psychopharmacology, 26(7), 1026–1035 https://doi org/10 1177/0269881111431752
Cavanna, F, Muller, S , De La Fuente, L A , Zamberlan, F, Palmucci, M , Janeckova, L , Kuchar, M , Pallavicini, C , & Tagliazucchi, E (2022) Microdosing with psilocybin mushrooms: A double-blind placebo-controlled study. Translational Psychiatry, 12(1), 307. https://doi.org/10.1038/s41398-022-02039-0
Cavarra, M., Falzone, A., Ramaekers, J. G., Kuypers, K. P. C., & Mento, C. (2022). Psychedelic-Assisted Psychotherapy A Systematic Review of Associated Psychological Interventions. Frontiers in Psychology, 13, 887255. https://doi.org/10.3389/fpsyg.2022.887255
Chadwick, B., Waller, D. G., & Edwards, J. G. (2005). Potentially hazardous drug interactions with psychotropics. Advances in Psychiatric Treatment, 11(6), 440–449. https://doi org/10 1192/apt 11 6 440
Charilaos, L. A., & Sofou, L. (2012). Psychedelic drugs as treatment: A look into the future of psychotherapy
Chary, M., Yi, D., & Manini, A. F. (2018). Candyflipping and Other Combinations: Identifying Drug–Drug Combinations from an Online Forum. Frontiers in Psychiatry, 9, 135. https://doi org/10 3389/fpsyt 2018 00135
Cherian, K., Shinozuka, K., Tabaac, B. J., Arenas, A., Beutler, B. D., Evans, V. D., Fasano, C., & Muir, O S (2024) Psychedelic Therapy: A Primer for Primary Care Clinicians Ibogaine American Journal of Therapeutics, 31(2), e133–e140
https://doi org/10 1097/MJT0000000000001723
Cherniak, A D , Mikulincer, M , Gruneau Brulin, J , & Granqvist, P (2024) Perceived attachment history predicts psychedelic experiences: A naturalistic study Journal of Psychedelic Studies, 8(1), 82–91 https://doi org/10 1556/2054 2024 00330
Cheung, K , Ehrenkranz, R , Hinkle, J T, & Yaden, D B (2024) Commentary: A framework for assessment of adverse events in psychedelic research. Journal of Psychopharmacology, 02698811241309623. https://doi.org/10.1177/02698811241309623
Cheung, K., Propes, C., Jacobs, E., Earp, B. D., & Yaden, D. B. (n.d.). Psychedelic group-based integration: Ethical assessment and initial recommendations. International Review of Psychiatry, 0(0), 1–11 https://doi org/10 1080/09540261 2024 2357678
Chi, Y., & Chen, H. (2023). Investigating Substance Use via Reddit: Systematic Scoping Review. Journal of Medical Internet Research, 25, e48905. https://doi.org/10.2196/48905
Ching, T. H. W., Amoroso, L., Bohner, C., D’Amico, E., Eilbott, J., Entezar, T., Fitzpatrick, M., Fram, G., Grazioplene, R., Hokanson, J., Jankovsky, A., Kichuk, S. A., Martins, B., Patel, P., Schaer, H , Shnayder, S , Witherow, C , Pittenger, C , & Kelmendi, B (2024) Safety, feasibility, tolerability, and clinical effects of repeated psilocybin dosing combined with non-directive support in the treatment of obsessive-compulsive disorder: Protocol for a randomized, waitlist-controlled trial with blinded ratings Frontiers in Psychiatry, 14, 1278823
https://doi.org/10.3389/fpsyt.2023.1278823
Ching, T H W, & Kelmendi, B (2025) A primer for culturally attuned psychedelic clinical trials https://doi.org/10.1556/2054.2025.00394
Christensen, J A , Fipps, D C , & Bostwick, J M (2023) To treat or not to treat? High-potency benzodiazepine use in a case of comorbid hallucinogen persisting perception disorder and alcohol use disorder. Experimental and Clinical Psychopharmacology, 31(2), 300–304. https://doi.org/10.1037/pha0000597
Ciaunica, A., & Safron, A. (2022). Disintegrating and Reintegrating the Self – (In)Flexible Self-Models in Depersonalisation and Psychedelic Experiences. PsyArXiv. https://doi org/10 31234/osf io/mah78
Cohen, S. (1960). Lysergic acid diethylamide: Side effects and complications. The Journal of Nervous and Mental Disease, 130, 30–40 https://doi org/10 1097/00005053-196001000-00005
Colcott, J., Guerin, A. A., Carter, O., Meikle, S., & Bedi, G. (2024). Side-effects of mdma-assisted psychotherapy: A systematic review and meta-analysis. Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 49(8), 1208–1226 https://doi org/10 1038/s41386-024-01865-8
Collins, H M (2024) Psychedelics for the Treatment of Obsessive–Compulsive Disorder: Efficacy and Proposed Mechanisms International Journal of Neuropsychopharmacology, 27(12), pyae057 https://doi org/10 1093/ijnp/pyae057
Coppola, M , & Mondola, R (2017) JWH-122 Consumption Adverse Effects: A Case of Hallucinogen Persisting Perception Disorder Five-Year Follow-Up Journal of Psychoactive Drugs, 49(3), 262–265 https://doi org/10 1080/02791072 2017 1316431
Cornfield, M , McBride, S , La Torre, J T, Zalewa, D , Gallo, J , Mahammadli, M , & Williams, M T. (2024). Exploring effects and experiences of ketamine in group couples therapy. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00302
Cowley-Court, T., Chenhall, R., Sarris, J., Bouso, J. C., Tófoli, L. F., Opaleye, E. S., Schubert, V., & Perkins, D. (2023). Life after Ayahuasca: A Qualitative Analysis of the Psychedelic Integration Experiences of 1630 Ayahuasca Drinkers from a Global Survey Psychoactives, 2(2), Article 2 https://doi org/10 3390/psychoactives2020014
Coyle, J. R., Presti, D. E., & Baggott, M. J. (n.d.). Quantitative Analysis of Narrative Reports of Psychedelic Drugs
Croarkin, P. E., Sutherland, I., & Ho, M.-F. (2024). Psychedelic Therapeutics for Adolescents: Safety, Opportunities, and Equipoise Journal of the American Academy of Child and Adolescent Psychiatry, S0890-8567(24)02061-6 https://doi org/10 1016/j jaac 2024 12 003
Curry, D W, Young, M B , Tran, A N , Daoud, G E , & Howell, L L (2018) Separating the agony from ecstasy: R(-)-3,4-methylenedioxymethamphetamine has prosocial and therapeutic-like effects without signs of neurotoxicity in mice Neuropharmacology, 128, 196–206 https://doi org/10 1016/j neuropharm 2017 10 003
Davis, A K , Agin-Liebes, G , España, M , Pilecki, B , & Luoma, J (2022) Attitudes and Beliefs about the Therapeutic Use of Psychedelic Drugs among Psychologists in the United States Journal of Psychoactive Drugs, 54(4), 309–318. https://doi.org/10.1080/02791072.2021.1971343
Davis, A. K., Barsuglia, J. P., Lancelotta, R., Grant, R. M., & Renn, E. (2018). The epidemiology of 5-methoxy-N, N-dimethyltryptamine (5-MeO-DMT) use: Benefits, consequences, patterns of use, subjective effects, and reasons for consumption. Journal of Psychopharmacology, 32(7), 779–792 https://doi org/10 1177/0269881118769063
Davis, A. K., Bates, M., Lund, E. M., Sepeda, N. D., Levin, A. W., Armstrong, S. B., Koffman, R., Hooyer, K , & Yehuda, R (n d ) The Epidemiology of Psychedelic Use Among United States Military Veterans Journal of Psychoactive Drugs, 0(0), 1–14 https://doi org/10 1080/02791072 2024 2401977
Davis, A K , Timmermann, C , Ortiz Bernal, A M , Lancelotta, R , Nayak, S , Sepeda, N D , Nikolaidis, A , & Griffiths, R R (2024) Translation and Initial Psychometric Evaluation of Spanish Versions of Three Psychedelic Acute Effects Measures: Mystical, Challenging, and Insight Experiences. Journal of Psychoactive Drugs, 56(4), 456–466. https://doi.org/10.1080/02791072.2023.2232379
Dawson, K., Carangan, A. M. J. M., Klunder, J., Carreras-Gallo, N., Sehgal, R., Megilligan, S., Askins, B. C., Perkins, N., Mendez, T. L., Smith, R., Dawson, M., Mallin, M., Higgins-Chen, A. T., & Dwaraka, V. B. (2024). Ketamine treatment effects on DNA methylation and Epigenetic
Biomarkers of aging (p 2024 09 10 24313258) medRxiv https://doi.org/10.1101/2024.09.10.24313258
Deane, G (2020) Dissolving the self: Active inference, psychedelics, and ego-dissolution Philosophy and the Mind Sciences, 1(I), 1–27. https://doi.org/10.33735/phimisci.2020.I.39
Denson, R (1969) Complications of therapy with lysergide Canadian Medical Association Journal, 101(11), 53–57.
Developing Guidelines and Competencies for the Training of Psychedelic Therapists (n d ) ResearchGate Retrieved January 14, 2025, from https://www.researchgate.net/publication/318022461 Developing Guidelines and Competenci es for the Training of Psychedelic Therapists
Devenot, N., Conner, T., & Doyle, R. (2022). Dark Side of the Shroom: Erasing Indigenous and Counterculture Wisdoms with Psychedelic Capitalism, and the Open Source Alternative: A Manifesto for Psychonauts† Anthropology of Consciousness, 33(2), 476–505 https://doi org/10 1111/anoc 12154
Devenot, N., Seale-Feldman, A., Smith, E., Noorani, T., Garcia-Romeu, A., & Johnson, M. W. (2022) Psychedelic Identity Shift: A Critical Approach to Set And Setting Kennedy Institute of Ethics Journal, 32(4), 359–399 https://doi org/10 1353/ken 2022 0022
Dollar, C B (2021) Recreation and Realization: Reported Motivations of Use Among Persons Who Consume Psychedelics in Non-Clinical Settings Journal of Qualitative Criminal Justice & Criminology https://doi org/10 21428/88de04a1 cb6fef95
Dos Santos, R G , Bouso, J C , Alcázar-Córcoles, M Á , & Hallak, J E C (2018) Efficacy, tolerability, and safety of serotonergic psychedelics for the management of mood, anxiety, and substance-use disorders: A systematic review of systematic reviews Expert Review of Clinical Pharmacology, 11(9), 889–902. https://doi.org/10.1080/17512433.2018.1511424
Dos Santos, R G , & Hallak, J E C (2024) Ayahuasca: Pharmacology, safety, and therapeutic effects. CNS Spectrums, 1–9. https://doi.org/10.1017/S109285292400213X
Dourron, H , Bradley, M , & Hendricks, P (2024) Psychedelics’ Uncertain Risks: A Reply to Myran et al. PsyArXiv. https://doi.org/10.31234/osf.io/vujpk
Dourron, H M , Nichols, C D , Simonsson, O , Bradley, M , Carhart-Harris, R , & Hendricks, P S (2023) 5-MeO-DMT: An atypical psychedelic with unique pharmacology, phenomenology & risk? Psychopharmacology. https://doi.org/10.1007/s00213-023-06517-1
Doyle, M A , Ling, S , Lui, L M W, Fragnelli, P, Teopiz, K M , Ho, R , Di Vincenzo, J D , Rosenblat, J. D., Gillissie, E. S., Nogo, D., Ceban, F., Jawad, M. Y., & McIntyre, R. S. (2022a). Hallucinogen persisting perceptual disorder: A scoping review covering frequency, risk factors,
prevention, and treatment Expert Opinion on Drug Safety, 21(6), 733–743
https://doi.org/10.1080/14740338.2022.2063273
Doyle, M A , Ling, S , Lui, L M W, Fragnelli, P, Teopiz, K M , Ho, R , Di Vincenzo, J D , Rosenblat, J. D., Gillissie, E. S., Nogo, D., Ceban, F., Jawad, M. Y., & McIntyre, R. S. (2022b). Hallucinogen persisting perceptual disorder: A scoping review covering frequency, risk factors, prevention, and treatment Expert Opinion on Drug Safety, 21(6), 733–743
https://doi org/10 1080/14740338 2022 2063273
DPS en HPPD: Signalering, diagnostiek en behandeling van persistente waarnemingsstoornissen na partydrugs (2024) ResearchGate
https://doi org/10 1007/s12501-016-0074-x
Dupuis, D (2021) Psychedelics as Tools for Belief Transmission Set, Setting, Suggestibility, and Persuasion in the Ritual Use of Hallucinogens Frontiers in Psychology, 12, 730031
https://doi org/10 3389/fpsyg 2021 730031
Dupuis, D , & Veissière, S (2022) Culture, context, and ethics in the therapeutic use of hallucinogens: Psychedelics as active super-placebos? Transcultural Psychiatry, 59(5), 571–578 https://doi org/10 1177/13634615221131465
Dyck, E (2018) Who Is Keeping Tabs? LSD Lessons from the Past for the Future In B C Labate & C Cavnar (Eds ), Plant Medicines, Healing and Psychedelic Science (pp 1–17) Springer International Publishing. https://doi.org/10.1007/978-3-319-76720-8 1
Dyck, E , & Dixon, J (2024) Completing the Circle: A History of Psychedelics and Harm Reduction. Current Topics in Behavioral Neurosciences. https://doi.org/10.1007/7854 2024 511
Dyck, E , & Elcock, C (2020) Reframing Bummer Trips: Scientific and Cultural Explanations to Adverse Reactions to Psychedelic Drug Use The Social History of Alcohol and Drugs, 34(2), 271–296. https://doi.org/10.1086/707512
Earleywine, M , Falabella, G S , Oliva, A B , & Low, F (2024) Acute Psychedelic Reactions, Post-Acute Changes in Dysfunctional Attitudes, and Psychedelic-Associated Changes in Wellbeing. Journal of Psychoactive Drugs, 1–10. https://doi.org/10.1080/02791072.2024.2421892
Earleywine, M., & Gomez, S. G. (2024). Is Personal Experience Essential for Effective Psychedelic Therapists?: The Challenges of Small, Accumulating Therapist Effects. Psychedelic Medicine, 2(3), 138–145 https://doi org/10 1089/psymed 2023 0054
Earleywine, M., & Herrmann, Z. M. (2022). Psychedelics for Psychiatric Disorders: Promise, Not Panacea Psychiatric Annals, 52(9), 354–358 https://doi org/10 3928/00485713-20220810-01
Eckernäs, E., Timmermann, C., Carhart-Harris, R., Röshammar, D., & Ashton, M. (2022). Population pharmacokinetic/pharmacodynamic modeling of the psychedelic experience induced
by N,N-dimethyltryptamine Implications for dose considerations Clinical and Translational Science, 15(12), 2928–2937. https://doi.org/10.1111/cts.13410
Edelsohn, G A , & Sisti, D (2023) Past Is Prologue: Ethical Issues in Pediatric Psychedelics Research and Treatment. Perspectives in Biology and Medicine, 66(1), 129–144. https://doi.org/10.1353/pbm.2023.0007
Edwards, D., Csontos, J., Pascoe, M. J., Westwell, A., Gillen, E., Bennett, C., Hannigan, B., Carrier, J., & Harden, J. (2023). A rapid scoping review of self-initiated harm reduction strategies for ecstasy (MDMA) users in recreational settings. In Review.
https://doi org/10 21203/rs 3 rs-2178425/v2
Ehrenkranz, R., Agrawal, M., Nayak, S. M., & Yaden, D. B. (2024). Adverse Events Should Not Be Surprising in Psychedelic Research Psychedelic Medicine
https://doi org/10 1089/psymed 2024 0006
Eisner, B (1997) Set, setting, and matrix Journal of Psychoactive Drugs, 29(2), 213–216
https://doi org/10 1080/02791072 1997 10400190
Ellison‐Wright, Z., & Sessa, B. (2015). A persisting perception disorder after cannabis use. Progress in Neurology and Psychiatry, 19(1), 10–13 https://doi org/10 1002/pnp 363
Elsey, J. W. B. (2017). Psychedelic drug use in healthy individuals: A review of benefits, costs, and implications for drug policy Drug Science, Policy and Law, 3, 2050324517723232 https://doi org/10 1177/2050324517723232
Emergency Department Visits Involving Hallucinogen Use and Risk of Schizophrenia Spectrum Disorder | Substance Use and Addiction Medicine | JAMA Psychiatry | JAMA Network (n d )
Retrieved January 12, 2025, from https://jamanetwork com/journals/jamapsychiatry/article-abstract/2825649
Engel, L B , Thal, S B , & Bright, S J (2022) Psychedelic Forum Member Preferences for Carer Experience and Consumption Behavior: Can “Trip Sitters” Help Inform Psychedelic Harm Reduction Services? Contemporary Drug Problems, 49(4), 356–368. https://doi.org/10.1177/00914509221121420
Engel, L. B., Thal, S., Bright, S. J., & Low, M. (2024). Psychedelic trip sitting, dosages and intensities: Supplementing clinical studies with anecdotal reports. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00377
Erritzoe, D., & Richards, W. A. (2017). Lessons to be learned from early psychedelic therapy in Denmark. Nordic Journal of Psychiatry, 71(7), 487–488.
https://doi org/10 1080/08039488 2017 1336252
Evans, J., & Joseph Holcomb, A. (n.d.). Guruism and Cultic Social Dynamics in Psychedelic Organisations pdf Dropbox Retrieved January 9, 2025, from
https://wwwdropbox com/scl/fi/qyi2rmw2gxlirpzpuuyde/Guruism-and-Cultic-Social-Dynamics-inPsychedelic-Organisations.pdf?dl=0&rlkey=czgo0yl96tulii9xjbbqoveb2
Evans, J , Robinson, O C , Argyri, E K , Suseelan, S , Murphy-Beiner, A , McAlpine, R , Luke, D., Michelle, K., & Prideaux, E. (2023). Extended difficulties following the use of psychedelic drugs: A mixed methods study. PLOS ONE, 18(10), e0293349.
https://doi org/10 1371/journal pone 0293349
Evans, V. D., Arenas, A., Shinozuka, K., Tabaac, B. J., Beutler, B. D., Cherian, K., Fasano, C., & Muir, O. S. (2024). Psychedelic Therapy: A Primer for Primary Care Clinicians Ketamine. American Journal of Therapeutics, 31(2), e155 https://doi org/10 1097/MJT0000000000001721
Eveloff, H. H. (1968). The LSD syndrome. A review. California Medicine, 109(5), 368–373.
Evens, R., Schmidt, M. E., Majić, T., & Schmidt, T. T. (2023). The psychedelic afterglow phenomenon: A systematic review of subacute effects of classic serotonergic psychedelics. Therapeutic Advances in Psychopharmacology, 13, 20451253231172254
https://doi org/10 1177/20451253231172254
Expert Opinion on Psychedelic-Assisted Psychotherapy for People with Psychotic Symptoms. (n d ) ResearchGate Retrieved January 14, 2025, from https://wwwresearchgate net/publication/358112937 Expert Opinion on Psychedelic-Assisted Psychotherapy for People with Psychotic Symptoms
Fadiman, J , & Korb, S (2019) Might Microdosing Psychedelics Be Safe and Beneficial? An Initial Exploration Journal of Psychoactive Drugs, 51(2), 118–122 https://doi.org/10.1080/02791072.2019.1593561
Falchi-Carvalho, M , Wießner, I , Silva, S R B , O Maia, L , Barros, H , Laborde, S , Arichelle, F, Tullman, S , Silva-Costa, N , Assunção, A , Almeida, R , Pantrigo, É J , Bolcont, R , Costa-Macedo, J. V., Arcoverde, E., Galvão-Coelho, N., Araujo, D. B., & Palhano-Fontes, F. (2024). Safety and tolerability of inhaled N,N-Dimethyltryptamine (BMND01 candidate): A phase I clinical trial European Neuropsychopharmacology: The Journal of the European College of Neuropsychopharmacology, 80, 27–35 https://doi org/10 1016/j euroneuro 2023 12 006
Family, N., Hendricks, P. S., Williams, L. T., Luke, D., Krediet, E., Maillet, E. L., & Raz, S. (2022). Safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg LSD in healthy participants within a novel intervention paradigm: A proof-of-concept study Journal of Psychopharmacology (Oxford, England), 36(3), 321–336 https://doi.org/10.1177/02698811211069103
Family, N , Maillet, E L , Williams, L T J , Krediet, E , Carhart-Harris, R L , Williams, T M , Nichols, C. D., Goble, D. J., & Raz, S. (2020). Safety, tolerability, pharmacokinetics, and pharmacodynamics of low dose lysergic acid diethylamide (LSD) in healthy older volunteers. Psychopharmacology, 237(3), 841–853. https://doi.org/10.1007/s00213-019-05417-7
Fang, S , Yang, X , & Zhang, W (2024) Efficacy and acceptability of psilocybin for primary or secondary depression: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Psychiatry, 15, 1359088. https://doi.org/10.3389/fpsyt.2024.1359088
Feduccia, A. A., Jerome, L., Mithoefer, M. C., & Holland, J. (2021). Discontinuation of medications classified as reuptake inhibitors affects treatment response of MDMA-assisted psychotherapy Psychopharmacology, 238(2), 581–588
https://doi org/10 1007/s00213-020-05710-w
Fernández-Calderón, F., Vidal-Giné, C., Rojas-Tejada, A. J., & Lozano-Rojas, Ó. M. (2020). Patterns of Simultaneous Polysubstance Use among Partygoers: Correlates and Differences in Adverse Acute Effects Experienced Journal of Psychoactive Drugs, 52(4), 344–356 https://doi org/10 1080/02791072 2020 1752959
Fogg, C , Michaels, T I , de la Salle, S , Jahn, Z W, & Williams, M T (2021) Ethnoracial health disparities and the ethnopsychopharmacology of psychedelic-assisted psychotherapies Experimental and Clinical Psychopharmacology, 29(5), 539–554 https://doi.org/10.1037/pha0000490
Fonzo, G A , Nemeroff, C B , & Kalin, N (2025) Psychedelics in Psychiatry: Oh, What A Trip! American Journal of Psychiatry, 182(1), 1–5. https://doi.org/10.1176/appi.ajp.20241025
Fonzo, G A , Wolfgang, A S , Barksdale, B R , Krystal, J H , Carpenter, L L , Kraguljac, N V, Grzenda, A., McDonald, W. M., Widge, A. S., Rodriguez, C. I., & Nemeroff, C. B. (2025). Psilocybin: From Psychiatric Pariah to Perceived Panacea. American Journal of Psychiatry, 182(1), 54–78. https://doi.org/10.1176/appi.ajp.20230682
Ford, H., Fraser, C. L., Solly, E., Clough, M., Fielding, J., White, O., & Van Der Walt, A. (2022). Hallucinogenic Persisting Perception Disorder: A Case Series and Review of the Literature. Frontiers in Neurology, 13, 878609 https://doi org/10 3389/fneur2022 878609
Ford, H. H., Fraser, C. C., Solly, E. E., Fielding, J. J., White, O., Rudaks, L. I., Watson, E., Lubomski, M , Edema-Hildebrand, F, Ahmad, K , Liang, C , Davis, R , Sue, C , & Leonards, S (n d ) 079 HALLUCINOGENIC PERSISTING PERCEPTION DISORDER: A CASE SERIES AND REVIEW OF THE LITERATURE
Forstmann, M , & Sagioglou, C (2021) New insights into the clinical and nonclinical effects of psychedelic substances: An integrative review PsyArXiv https://doi org/10 31234/osf io/2489x
Fradkin, D (2024) Breaking through the doors of perception, consciousness, and existence: To what extent does psychedelic phenomenology ontologically depend on external factors? Journal of Psychedelic Studies, 8(1), 122–141 https://doi org/10 1556/2054 2022 00168
Freitas, R R , Gotsis, E S , Gallo, A T, Fitzgibbon, B M , Bailey, N W, & Fitzgerald, P B (2024) The safety of psilocybin-assisted psychotherapy: A systematic review The Australian
and New Zealand Journal of Psychiatry, 48674241289024
https://doi.org/10.1177/00048674241289024
Friedman, M L , Malakooti, M , Smith, C , Harris, Z L , & Wainwright, M (2015) Ingestion of Synthetic Street Drug “25-I” (25I-NBOMe) Causing Type B Lactic Acidosis and Multi-Organ Dysfunction. Journal of Medical Cases, 6(3), 125–127. https://doi.org/10.14740/jmc2023w
Fuentes, J. J., Fonseca, F., Elices, M., Farré, M., & Torrens, M. (2020). Therapeutic Use of LSD in Psychiatry: A Systematic Review of Randomized-Controlled Clinical Trials. Frontiers in Psychiatry, 10. https://doi.org/10.3389/fpsyt.2019.00943
G Lerner, A., & Lev-Ran, S. (2015). LSD-associated “Alice in Wonderland Syndrome”(AIWS): A Hallucinogen Persisting Perception Disorder (HPPD) Case Report. The Israel Journal of Psychiatry and Related Sciences, 52(1), 67–68
G Lerner, A., Rudinski, D., Bor, O., & Goodman, C. (2014). Flashbacks and HPPD: A Clinical-oriented Concise Review The Israel Journal of Psychiatry and Related Sciences, 51(4), 296–301
Gandy, S., Forstmann, M., Carhart-Harris, R. L., Timmermann, C., Luke, D., & Watts, R. (2020). The potential synergistic effects between psychedelic administration and nature contact for the improvement of mental health Health Psychology Open, 7(2), 2055102920978123 https://doi org/10 1177/2055102920978123
Garcia-Romeu, A , Davis, A K , Erowid, E , Erowid, F, Griffiths, R R , & Johnson, M W (2020) Persisting Reductions in Cannabis, Opioid, and Stimulant Misuse After Naturalistic Psychedelic Use: An Online Survey. Frontiers in Psychiatry, 10, 955. https://doi.org/10.3389/fpsyt.2019.00955
Garcia-Romeu, A , & Richards, W A (2018) Current perspectives on psychedelic therapy: Use of serotonergic hallucinogens in clinical interventions. International Review of Psychiatry, 30(4), 291–316. https://doi.org/10.1080/09540261.2018.1486289
Garel, N., Thibault Lévesque, J., Sandra, D. A., Lessard-Wajcer, J., Solomonova, E., Lifshitz, M., Richard-Devantoy, S., & Greenway, K. T. (2023). Imprinting: Expanding the extra-pharmacological model of psychedelic drug action to incorporate delayed influences of sets and settings Frontiers in Human Neuroscience, 17, 1200393 https://doi org/10 3389/fnhum 2023 1200393
Gashi, L , Sandberg, S , & Pedersen, W (2021) Making “bad trips” good: How users of psychedelics narratively transform challenging trips into valuable experiences International Journal of Drug Policy, 87, 102997 https://doi org/10 1016/j drugpo 2020 102997
Gasser, P, Holstein, D , Michel, Y, Doblin, R , Yazar-Klosinski, B , Passie, T, & Brenneisen, R (2014) Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety
Associated With Life-threatening Diseases Journal of Nervous & Mental Disease, 202(7), 513–520. https://doi.org/10.1097/NMD.0000000000000113
Gatch, M B , Hoch, A , & Carbonaro, T M (2021) Discriminative Stimulus Effects of Substituted Tryptamines in Rats. ACS Pharmacology & Translational Science, 4(2), 467–471. https://doi.org/10.1021/acsptsci.0c00173
GCU, Lahore, Pakistan, & Shabir, K. (2024). Psilocybin Microdosing for Anxiety Relief in Young Adults: A Comparative Review of Emerging Evidence. Premier Journal of Science.
https://doi.org/10.70389/PJS.100036
Geller, J., & Whitney, E. (2024). Therapeutic Potential of MDMA- and Psychedelic-Assisted Psychotherapy for Adolescent Depression and Trauma. Current Psychiatry Reports.
https://doi org/10 1007/s11920-024-01577-2
George, D. R., Hanson, R., Wilkinson, D., & Garcia-Romeu, A. (2022). Ancient Roots of Today’s Emerging Renaissance in Psychedelic Medicine Culture, Medicine, and Psychiatry, 46(4), 890–903 https://doi org/10 1007/s11013-021-09749-y
Geppert, C. (2022). Psychedelics and the Military: What a Long, Strange Trip It’s Been. Federal Practitioner, 39(10) https://doi org/10 12788/fp 0332
Gezon, L. L. (2024). Community-based psychedelic integration and social efficacy: An ethnographic study in the Southeastern United States Journal of Psychedelic Studies https://doi org/10 1556/2054 2024 00381
Ghaznavi, S , Ruskin, J N , Haggerty, S J , King, F, & Rosenbaum, J F (2025) Primum Non Nocere: The Onus to Characterize the Potential Harms of Psychedelic Treatment American Journal of Psychiatry, 182(1), 47–53 https://doi org/10 1176/appi ajp 20230914
Girn, M , Roseman, L , Bernhardt, B , Smallwood, J , Carhart-Harris, R , & Spreng, R N (2020) Serotonergic psychedelic drugs LSD and psilocybin reduce the hierarchical differentiation of unimodal and transmodal cortex Neuroscience https://doi org/10 1101/2020 05 01 072314
Glue, P, Cape, G , Tunnicliff, D , Lockhart, M , Lam, F, Hung, N , Hung, C T, Harland, S , Devane, J , Crockett, R S , Howes, J , Darpo, B , Zhou, M , Weis, H , & Friedhoff, L (2016) Ascending Single-Dose, Double-Blind, Placebo-Controlled Safety Study of Noribogaine in Opioid-Dependent Patients. Clinical Pharmacology in Drug Development, 5(6), 460–468. https://doi.org/10.1002/cpdd.254
Glue, P., Lockhart, M., Lam, F., Hung, N., Hung, C.-T., & Friedhoff, L. (2015). Ascending-dose study of noribogaine in healthy volunteers: Pharmacokinetics, pharmacodynamics, safety, and tolerability Journal of Clinical Pharmacology, 55(2), 189–194 https://doi org/10 1002/jcph 404
Glue, P., Winter, H., Garbe, K., Jakobi, H., Lyudin, A., Lenagh-Glue, Z., & Hung, C. T. (2015). Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20mg
dose of ibogaine in healthy volunteers Journal of Clinical Pharmacology, 55(6), 680–687 https://doi.org/10.1002/jcph.471
Glynos, N G , Aday, J S , Kruger, D , Boehnke, K F, Lake, S , & Lucas, P (2024) Psychedelic substitution: Altered substance use patterns following psychedelic use in a global survey. Frontiers in Psychiatry, 15, 1349565. https://doi.org/10.3389/fpsyt.2024.1349565
Glynos, N. G., Fields, C. W., Barron, J., Herberholz, M., Kruger, D. J., & Boehnke, K. F. (2023). Naturalistic Psychedelic Use: A World Apart from Clinical Care. Journal of Psychoactive Drugs, 55(4), 379–388. https://doi.org/10.1080/02791072.2022.2108356
Goldberg, S. B., Shechet, B., Nicholas, C. R., Ng, C. W., Deole, G., Chen, Z., & Raison, C. L. (2020). Post-acute psychological effects of classical serotonergic psychedelics: A systematic review and meta-analysis Psychological Medicine, 50(16), 2655–2666
https://doi org/10 1017/S003329172000389X
Golden, T L , Magsamen, S , Sandu, C C , Lin, S , Roebuck, G M , Shi, K M , & Barrett, F S (2022a) Effects of Setting on Psychedelic Experiences, Therapies, and Outcomes: A Rapid Scoping Review of the Literature Current Topics in Behavioral Neurosciences, 56, 35–70
https://doi org/10 1007/7854 2021 298
Golden, T L , Magsamen, S , Sandu, C C , Lin, S , Roebuck, G M , Shi, K M , & Barrett, F S (2022b) Effects of Setting on Psychedelic Experiences, Therapies, and Outcomes: A Rapid Scoping Review of the Literature. In F. S. Barrett & K. H. Preller (Eds.), Disruptive Psychopharmacology (Vol. 56, pp. 35–70). Springer International Publishing. https://doi.org/10.1007/7854 2021 298
Goldy, S. P., Du, B. A., Rohde, J. S., Nayak, S. M., Strickland, J. C., Ehrenkranz, R., Levine, M., Barrett, F. S., & Yaden, D. B. (2024). Psychedelic risks and benefits: A cross-sectional survey study Journal of Psychopharmacology, 02698811241292951
https://doi org/10 1177/02698811241292951
Gomez-Escolar, A , Folch-Sanchez, D , Stefaniuk, J , Swithenbank, Z , Nisa, A , Braddick, F, Idrees Chaudhary, N , Van Der Meer, P B , & Batalla, A (2024) Current Perspectives on the Clinical Research and Medicalization of Psychedelic Drugs for Addiction Treatments: Safety, Efficacy, Limitations and Challenges CNS Drugs, 38(10), 771–789 https://doi.org/10.1007/s40263-024-01101-3
Gorman, I , Nielson, E M , Molinar, A , Cassidy, K , & Sabbagh, J (2021) Psychedelic Harm Reduction and Integration: A Transtheoretical Model for Clinical Practice. Frontiers in Psychology, 12, 645246. https://doi.org/10.3389/fpsyg.2021.645246
Gotvaldová, K., Hájková, K., Borovička, J., Jurok, R., Cihlářová, P., & Kuchař, M. (2021).
Stability of psilocybin and its four analogs in the biomass of the psychotropic mushroom
Psilocybe cubensis Drug Testing and Analysis, 13(2), 439–446 https://doi.org/10.1002/dta.2950
Griffin, C , & Knight, A (2024) Treatment and therapy of mental health conditions in the Global South using psychedelics: A scoping review and narrative synthesis. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00333
Griffiths, R. R., Hurwitz, E. S., Davis, A. K., Johnson, M. W., & Jesse, R. (2019). Survey of subjective “God encounter experiences”: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT. PLOS ONE, 14(4), e0214377 https://doi org/10 1371/journal pone 0214377
Griffiths, R. R., Johnson, M. W., Carducci, M. A., Umbricht, A., Richards, W. A., Richards, B. D., Cosimano, M P, & Klinedinst, M A (2016) Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial Journal of Psychopharmacology, 30(12), 1181–1197 https://doi org/10 1177/0269881116675513
Griffiths, R R , Richards, W A , McCann, U , & Jesse, R (2006) Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology, 187(3), 268–283. https://doi.org/10.1007/s00213-006-0457-5
Grob, C. S., Bossis, A. P., & Griffiths, R. R. (2022). Use of the Classic Hallucinogen Psilocybin for Treatment of Existential Distress Associated with Cancer. In J. L. Steel & B. I. Carr (Eds.), Psychological Aspects of Cancer (pp. 69–89). Springer International Publishing. https://doi org/10 1007/978-3-030-85702-8 5
Gross, S. R., Barrett, S. P., Shestowsky, J. S., & Pihl, R. O. (2002). Ecstasy and Drug Consumption Patterns: A Canadian Rave Population Study The Canadian Journal of Psychiatry, 47(6), 546–551 https://doi org/10 1177/070674370204700606
Gründer, G , & Jungaberle, H (2021) The Potential Role of Psychedelic Drugs in Mental Health Care of the Future Pharmacopsychiatry, 54(4), 191–199 https://doi org/10 1055/a-1486-7386
Gukasyan, N., Davis, A. K., Barrett, F. S., Cosimano, M. P., Sepeda, N. D., Johnson, M. W., & Griffiths, R R (2022) Efficacy and safety of psilocybin-assisted treatment for major depressive disorder: Prospective 12-month follow-up Journal of Psychopharmacology (Oxford, England), 36(2), 151–158 https://doi org/10 1177/02698811211073759
Gukasyan, N , Griffiths, R R , Yaden, D B , Antoine, D G , & Nayak, S M (2023) Attenuation of psilocybin mushroom effects during and after SSRI/SNRI antidepressant use Journal of Psychopharmacology (Oxford, England), 37(7), 707–716. https://doi.org/10.1177/02698811231179910
Gukasyan, N , & Nayak, S M (2022) Psychedelics, placebo effects, and set and setting: Insights from common factors theory of psychotherapy. Transcultural Psychiatry, 59(5), 652–664. https://doi.org/10.1177/1363461520983684
Guo, H., Wang, B., Yuan, S., Wu, S., Liu, J., He, M., & Wang, J. (2022). Neurological Adverse Events Associated With Esketamine: A Disproportionality Analysis for Signal Detection Leveraging the FDA Adverse Event Reporting System Frontiers in Pharmacology, 13, 849758 https://doi org/10 3389/fphar2022 849758
Hackl, B., Todt, H., Kubista, H., Hilber, K., & Koenig, X. (2022). Psilocybin Therapy of Psychiatric Disorders Is Not Hampered by hERG Potassium Channel-Mediated Cardiotoxicity The International Journal of Neuropsychopharmacology, 25(4), 280–282 https://doi org/10 1093/ijnp/pyab085
Haden, M , Emerson, B , & Tupper, K W (2016) A Public-Health-Based Vision for the Management and Regulation of Psychedelics Journal of Psychoactive Drugs, 48(4), 243–252 https://doi org/10 1080/02791072 2016 1202459
Haden, M , & Woods, B (2020) LSD Overdoses: Three Case Reports Journal of Studies on Alcohol and Drugs, 81(1), 115–118 https://doi org/10 15288/jsad 2020 81 115
Haft, S L , Downey, A E , Raymond-Flesch, M , Fernandes-Osterhold, G , Bradley, E R , O’Donovan, A , & Woolley, J (2025) A systematic review of participant diversity in psychedelic-assisted psychotherapy trials. Psychiatry Research, 345, 116359. https://doi.org/10.1016/j.psychres.2025.116359
Haijen, E. C. H. M., Kaelen, M., Roseman, L., Timmermann, C., Kettner, H., Russ, S., Nutt, D., Daws, R. E., Hampshire, A. D. G., Lorenz, R., & Carhart-Harris, R. L. (2018). Predicting Responses to Psychedelics: A Prospective Study. Frontiers in Pharmacology, 9, 897. https://doi org/10 3389/fphar2018 00897
Halpern, J. H., Lerner, A. G., & Passie, T. (2018). A Review of Hallucinogen Persisting Perception Disorder (HPPD) and an Exploratory Study of Subjects Claiming Symptoms of HPPD Current Topics in Behavioral Neurosciences, 36, 333–360 https://doi org/10 1007/7854 2016 457
Halpern, J H , & Pope, H G (1999) Do hallucinogens cause residual neuropsychological toxicity? Drug and Alcohol Dependence, 53(3), 247–256
https://doi org/10 1016/s0376-8716(98)00129-x
Halpern, J H , & Pope, H G (2003a) Hallucinogen persisting perception disorder: What do we know after 50 years? Drug and Alcohol Dependence, 69(2), 109–119
https://doi.org/10.1016/s0376-8716(02)00306-x
Halpern, J H , & Pope, H G (2003b) Hallucinogen persisting perception disorder: What do we know after 50 years? Drug and Alcohol Dependence, 69(2), 109–119.
https://doi.org/10.1016/S0376-8716(02)00306-X
Halpern, J. H., Sherwood, A. R., Hudson, J. I., Gruber, S., Kozin, D., & Pope, H. G. (2011).
Residual neurocognitive features of long-term ecstasy users with minimal exposure to other drugs Addiction (Abingdon, England), 106(4), 777–786
https://doi org/10 1111/j 1360-0443 2010 03252 x
Halpern, J. H., Sherwood, A. R., Passie, T., Blackwell, K. C., & Ruttenber, A. J. (2008). Evidence of health and safety in American members of a religion who use a hallucinogenic sacrament
Medical Science Monitor: International Medical Journal of Experimental and Clinical Research, 14(8), SR15-22
Hartogsohn, I (2016) Set and setting, psychedelics and the placebo response: An extra-pharmacological perspective on psychopharmacology Journal of Psychopharmacology (Oxford, England), 30(12), 1259–1267 https://doi org/10 1177/0269881116677852
Hartogsohn, I (2017) Constructing drug effects: A history of set and setting Drug Science, Policy and Law, 3, 2050324516683325 https://doi org/10 1177/2050324516683325
Hartogsohn, I (2021) Set and Setting in the Santo Daime Frontiers in Pharmacology, 12, 651037 https://doi org/10 3389/fphar2021 651037
Hartogsohn, I (2022) Modalities of the psychedelic experience: Microclimates of set and setting in hallucinogen research and culture Transcultural Psychiatry, 59(5), 579–591 https://doi.org/10.1177/13634615221100385
Hartogsohn, I (2024) Set and Setting for Psychedelic Harm Reduction Current Topics in Behavioral Neurosciences https://doi org/10 1007/7854 2024 509
Hartogsohn, I , & Petranker, R (2022) Set and setting in microdosing: An oft-overlooked principle Psychopharmacology, 239(12), 3771–3777 https://doi.org/10.1007/s00213-022-06249-8
Hase, A , Erdmann, M , Limbach, V, & Hasler, G (2022) Analysis of recreational psychedelic substance use experiences classified by substance. Psychopharmacology, 239(2), 643–659. https://doi.org/10.1007/s00213-022-06062-3
Haslacher, D , Novkovic, N , Buthut, M , Heinz, A , & Soekadar, S R (2022) Pathological Delta Oscillations in Hallucinogen Persisting Perception Disorder: A Case Report. Frontiers in Psychiatry, 13, 867314. https://doi.org/10.3389/fpsyt.2022.867314
Hasler, F., Grimberg, U., Benz, M. A., Huber, T., & Vollenweider, F. X. (2004). Acute psychological and physiological effects of psilocybin in healthy humans: A double-blind,
placebo-controlled dose-effect study Psychopharmacology, 172(2), 145–156 https://doi.org/10.1007/s00213-003-1640-6
Healy, C J (2021) The acute effects of classic psychedelics on memory in humans Psychopharmacology, 238(3), 639–653. https://doi.org/10.1007/s00213-020-05756-w
Hendin, H M , & Penn, A D (2021) An episode of mania following self‐reported ingestion of psilocybin mushrooms in a woman previously not diagnosed with bipolar disorder: A case report. Bipolar Disorders, 23(7), 733–735. https://doi.org/10.1111/bdi.13095
Hendricks, P S , Copes, H , Family, N , Williams, L T, Luke, D , & Raz, S (2022) Perceptions of safety, subjective effects, and beliefs about the clinical utility of lysergic acid diethylamide in healthy participants within a novel intervention paradigm: Qualitative results from a proof-of-concept study Journal of Psychopharmacology (Oxford, England), 36(3), 337–347 https://doi org/10 1177/02698811211055855
Hendricks, P S , Crawford, M S , Cropsey, K L , Copes, H , Sweat, N W, Walsh, Z , & Pavela, G (2018) The relationships of classic psychedelic use with criminal behavior in the United States adult population Journal of Psychopharmacology (Oxford, England), 32(1), 37–48
https://doi org/10 1177/0269881117735685
Hendricks, P S , Thorne, C B , Clark, C B , Coombs, D W, & Johnson, M W (2015) Classic psychedelic use is associated with reduced psychological distress and suicidality in the United States adult population. Journal of Psychopharmacology, 29(3), 280–288. https://doi.org/10.1177/0269881114565653
Hendy, K. (2018). Placebo Problems: Boundary Work in the Psychedelic Science Renaissance. In B. C. Labate & C. Cavnar (Eds.), Plant Medicines, Healing and Psychedelic Science (pp. 151–166). Springer International Publishing. https://doi.org/10.1007/978-3-319-76720-8 9
Henningfield, J. E., Ashworth, J., Heal, D. J., & Smith, S. L. (2023). Psychedelic drug abuse potential assessment for new drug applications and controlled substance scheduling: A United States perspective Journal of Psychopharmacology (Oxford, England), 37(1), 33–44
https://doi org/10 1177/02698811221140004
Henningfield, J. E., Wang, D. W., & Huestis, M. A. (2021). Kratom Abuse Potential 2021: An Updated Eight Factor Analysis Frontiers in Pharmacology, 12, 775073
https://doi org/10 3389/fphar2021 775073
Henríquez-Hernández, L A , Rojas-Hernández, J , Quintana-Hernández, D J , & Borkel, L F (2023) Hofmann vs Paracelsus: Do Psychedelics Defy the Basics of Toxicology?-A Systematic Review of the Main Ergolamines, Simple Tryptamines, and Phenylethylamines Toxics, 11(2), 148. https://doi.org/10.3390/toxics11020148
Hermle, L , Kovar, K -A , Hewer, W, & Ruchsow, M (2008) [Hallucinogen-induced psychological disorders]. Fortschritte Der Neurologie-Psychiatrie, 76(6), 334–342. https://doi.org/10.1055/s-2008-1038191
Hermle, L., Ruchsow, M., & Täschner, K. (2015). Halluzinogen-induzierte Persistierende Wahrnehmungsstörung (HPPD) und Flashback-Phänomene – Differenzialdiagnose und Erklärungsmodelle Fortschritte der Neurologie · Psychiatrie, 83(09), 506–515 https://doi org/10 1055/s-0035-1553717
Hermle, L., Simon, M., Ruchsow, M., & Geppert, M. (n.d.). Hallucinogen-persisting perception disorder Therapeutic Advances in Psychopharmacology
Herrmann, Z., Levin, A. W., Cole, S. P., Slabaugh, S., Barnett, B., Penn, A., Jain, R., Raison, C., Rajanna, B , & Jain, S (2023) Psychedelic Use Among Psychiatric Medication Prescribers: Effects on Well-Being, Depression, Anxiety, and Associations with Patterns of Use, Reported Harms, and Transformative Mental States Psychedelic Medicine, 1(3), 139–149 https://doi org/10 1089/psymed 2023 0030
Hibicke, M , Billac, G , & Nichols, C D (2024) Preadministration of Lorazepam Reduces Efficacy and Longevity of Antidepressant-Like Effect from a Psychedelic Psychedelic Medicine, 2(1), 10–14. https://doi.org/10.1089/psymed.2023.0037
Hinkle, J T, Graziosi, M , Nayak, S M , & Yaden, D B (2024) Adverse Events in Studies of Classic Psychedelics: A Systematic Review and Meta-Analysis. JAMA Psychiatry, 81(12), 1225–1235. https://doi.org/10.1001/jamapsychiatry.2024.2546
Hipólito, I., Mago, J., Rosas, F. E., & Carhart-Harris, R. (2023). Pattern breaking: A complex systems approach to psychedelic medicine. Neuroscience of Consciousness, 2023(1), niad017. https://doi.org/10.1093/nc/niad017
Hirschfeld, T., Smit-Rigter, L., Van Der Gouwe, D., Reiche, S., Stöver, H., & Majić, T. (2021). Safer Tripping: Serotonergic Psychedelics and Drug Checking. Submission and Detection Rates, Potential Harms, and Challenges for Drug Analysis Current Addiction Reports, 8(3), 389–398 https://doi org/10 1007/s40429-021-00385-5
Hochstetler, A., & Peters, D. J. (2023). Geography of poly-substance drug mortality. Journal of Criminal Justice, 86, 102044 https://doi org/10 1016/j jcrimjus 2023 102044
Hoener, S., Wolfgang, A., Nissan, D., & Howe, E. (2024). Ethical considerations for psychedelic-assisted therapy in military clinical settings Journal of Medical Ethics, 50(4), 258–262 https://doi org/10 1136/jme-2023-108943
Holoyda, B J (2023) Malpractice and Other Civil Liability in Psychedelic Psychiatry Psychiatric Services (Washington, D C ), 74(1), 92–95 https://doi org/10 1176/appi ps 20220528
Holze, F, Becker, A M , Kolaczynska, K E , Duthaler, U , & Liechti, M E (2023) Pharmacokinetics and Pharmacodynamics of Oral Psilocybin Administration in Healthy Participants. Clinical Pharmacology and Therapeutics, 113(4), 822–831. https://doi org/10 1002/cpt 2821
Holze, F., Caluori, T. V., Vizeli, P., & Liechti, M. E. (2022). Safety pharmacology of acute LSD administration in healthy subjects Psychopharmacology, 239(6), 1893–1905 https://doi org/10 1007/s00213-021-05978-6
Holze, F., Vizeli, P., Ley, L., Müller, F., Dolder, P., Stocker, M., Duthaler, U., Varghese, N., Eckert, A , Borgwardt, S , & Liechti, M E (2021) Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 46(3), 537–544. https://doi.org/10.1038/s41386-020-00883-6
Honk, L , Stenfors, C U D , Goldberg, S B , Hendricks, P S , Osika, W, Dourron, H M , Lebedev, A , Petrovic, P, & Simonsson, O (2024) Longitudinal associations between psychedelic use and psychotic symptoms in the United States and the United Kingdom. Journal of Affective Disorders, 351, 194–201. https://doi.org/10.1016/j.jad.2024.01.197
Honyiglo, E., Franchi, A., Cartiser, N., Bottinelli, C., Advenier, A.-S., Bévalot, F., & Fanton, L. (2019). Unpredictable Behavior Under the Influence of “Magic Mushrooms”: A Case Report and Review of the Literature Journal of Forensic Sciences, 64(4), 1266–1270 https://doi org/10 1111/1556-4029 13982
Hooyer, K., Applbaum, K., & Kasza, D. (2023). Altered States of Combat: Veteran Trauma and the Quest for Novel Therapeutics in Psychedelic Substances Journal of Humanistic Psychology, 63(6), 744–763 https://doi org/10 1177/0022167820904523
Horita, A , & Dille, J M (1954) Pyretogenic effect of lysergic acid diethylamide Science (New York, N Y), 120(3131), 1100–1101 https://doi org/10 1126/science 120 3131 1100
Hovmand, O R , Poulsen, E D , Arnfred, S , & Storebø, O J (2023) Risk of bias in randomized clinical trials on psychedelic medicine: A systematic review Journal of Psychopharmacology, 37(7), 649–659 https://doi org/10 1177/02698811231180276
How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe? (2024) AMA Journal of Ethics, 26(11), E842-849 https://doi org/10 1001/amajethics 2024 842
Hu, X , Gorman, I , & Nielson, E (2024) Psychedelic Harm Reduction and Integration: A Transtheoretical Model for Clinical Practice Current Topics in Behavioral Neurosciences https://doi.org/10.1007/7854 2024 529
Husain, M I , Umer, M , & Mulsant, B H (2022) Can the revival of serotonergic psychedelic drugs as treatments for mental disorders help to characterize their risks and benefits? Expert Opinion on Drug Safety, 21(6), 721–724. https://doi.org/10.1080/14740338.2022.2063274
Hutten, N. R. P. W., Mason, N. L., Dolder, P. C., & Kuypers, K. P. C. (2019). Motives and Side-Effects of Microdosing With Psychedelics Among Users. International Journal of Neuropsychopharmacology, 22(7), 426–434 https://doi org/10 1093/ijnp/pyz029
Hyde, C., Glancy, G., Omerod, P., Hall, D., & Taylor, G. S. (1978). Abuse of Indigenous Psilocybin Mushrooms: A New Fashion and Some Psychiatric Complications. British Journal of Psychiatry, 132(6), 602–604 https://doi org/10 1192/bjp 132 6 602
Hysek, C. M., Vollenweider, F. X., & Liechti, M. E. (2010). Effects of a beta-blocker on the cardiovascular response to MDMA (Ecstasy) Emergency Medicine Journal: EMJ, 27(8), 586–589 https://doi org/10 1136/emj 2009 079905
Iaria, G , Fox, C J , Scheel, M , Stowe, R M , & Barton, J J S (2010) A case of persistent visual hallucinations of faces following LSD abuse: A functional Magnetic Resonance Imaging study Neurocase, 16(2), 106–118 https://doi org/10 1080/13554790903329141
Inclusion of people of color in psychedelic-assisted psychotherapy: A review of the literature | BMC Psychiatry (n d ) Retrieved February 27, 2025, from https://link springercom/article/10 1186/s12888-018-1824-6?fbclid=IwAR1al6a0H9j2rjbeZOs C N 7pSk6Xf78c9zw1ujjIQ8BNOsi2IZI2g7KhEM
Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns. (n.d.). Blossom. Retrieved January 4, 2025, from https://blossomanalysis.com/papers/integration-in-psychedelic-assisted-treatments-recurring-the mes-in-current-providers-definitions-challenges-and-concerns/
Integration in Psychedelic-Assisted Treatments: Recurring Themes in Current Providers’ Definitions, Challenges, and Concerns Mitch Earleywine, Fiona Low, Carmen Lau, Joseph De Leo, 2022 (n d ) Retrieved January 4, 2025, from https://journals sagepub com/doi/abs/10 1177/00221678221085800
Irvine, A., & Luke, D. (2022). Apophenia, absorption and anxiety: Evidence for individual differences in positive and negative experiences of Hallucinogen Persisting Perceptual Disorder Journal of Psychedelic Studies, 6(2), 88–103 https://doi org/10 1556/2054 2022 00195
Ivory, S T, Rotella, J -A , Schumann, J , & Greene, S L (2022) A cluster of 25B-NBOH poisonings following exposure to powder sold as lysergic acid diethylamide (LSD) Clinical Toxicology, 60(8), 966–969 https://doi org/10 1080/15563650 2022 2053150
Izmi, N , Carhart-Harris, R L , & Kettner, H (2024a) Psychological effects of psychedelics in adolescents Frontiers in Child and Adolescent Psychiatry, 3 https://doi org/10 3389/frcha 2024 1364617
Izmi, N , Carhart-Harris, R L , & Kettner, H (2024b) Psychological effects of psychedelics in adolescents. Frontiers in Child and Adolescent Psychiatry, 3. https://doi.org/10.3389/frcha.2024.1364617
Jacobs, E. (2023). Transformative experience and informed consent to psychedelic-assisted psychotherapy. Frontiers in Psychology, 14, 1108333. https://doi org/10 3389/fpsyg 2023 1108333
Jagtiani, A. (2024). Novel treatments of depression: Bridging the gap in current therapeutic approaches. Exploration of Neuroscience, 3(4), 272–286. https://doi org/10 37349/en 2024 00049
Jahn, Z. W., Lopez, J., Salle, S. de la, Faber, S., & Williams, M. T. (2021). Racial/ethnic differences in prevalence of hallucinogen use by age cohort: Findings from the 2018 National Survey on Drug Use and Health https://doi org/10 1556/2054 2021 00166
James, E , Erritzoe, D , Benway, T, Joel, Z , Timmermann, C , Good, M , Agnorelli, C , Weiss, B M , Barba, T, Campbell, G , Baker Jones, M , Hughes, C , Topping, H , Boyce, M , & Routledge, C (2024) Safety, tolerability, pharmacodynamic and wellbeing effects of SPL026 (dimethyltryptamine fumarate) in healthy participants: A randomized, placebo-controlled phase 1 trial. Frontiers in Psychiatry, 14, 1305796. https://doi.org/10.3389/fpsyt.2023.1305796
Jegede, O , Nunes, J C , Tumenta, T, Black, C , & Aquino, J P D (2024) What Would Equitable Harm Reduction Look Like? AMA Journal of Ethics, 26(7), 572–579. https://doi.org/10.1001/amajethics.2024.572
Jiang, Y., Du, Z., Shen, Y., Zhou, Q., & Zhu, H. (2023). The correlation of Esketamine with specific adverse events: A deep dive into the FAERS database. European Archives of Psychiatry and Clinical Neuroscience. https://doi.org/10.1007/s00406-023-01732-5
Jivanescu, V. (2022). Long-term transformative effects and integration challenges of psychedelic experiences: A mixed methods phenomenological study of the Romanian population. Consciousness, Spirituality & Transpersonal Psychology, 3, 1–17 https://doi org/10 53074/cstp 2022 29
Johansen, P.-Ø., & Krebs, T. S. (2015). Psychedelics not linked to mental health problems or suicidal behavior: A population study Journal of Psychopharmacology, 29(3), 270–279 https://doi org/10 1177/0269881114568039
Johns, B (2022) Narrative therapy in psychedelic harm reduction: Supporting safety, agency and meaning-making The International Journal of Narrative Therapy and Community Work, 2022(2), 61–71 https://doi org/10 4320/MCBZ5745
Johnson, M , Richards, W, & Griffiths, R (2008a) Human hallucinogen research: Guidelines for safety Journal of Psychopharmacology (Oxford, England), 22(6), 603–620 https://doi org/10 1177/0269881108093587
Johnson, M , Richards, W, & Griffiths, R (2008b) Human hallucinogen research: Guidelines for safety. Journal of Psychopharmacology, 22(6), 603–620. https://doi.org/10.1177/0269881108093587
Johnson, M. W., Garcia-Romeu, A., Cosimano, M. P., & Griffiths, R. R. (2014). Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. Journal of Psychopharmacology, 28(11), 983–992 https://doi org/10 1177/0269881114548296
Johnson, M. W., Griffiths, R. R., Hendricks, P. S., & Henningfield, J. E. (2018). The abuse potential of medical psilocybin according to the 8 factors of the Controlled Substances Act. Neuropharmacology, 142, 143–166 https://doi org/10 1016/j neuropharm 2018 05 012
Johnson, M. W., Hendricks, P. S., Barrett, F. S., & Griffiths, R. R. (2019). Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function Pharmacology & Therapeutics, 197, 83–102 https://doi org/10 1016/j pharmthera 2018 11 010
Johnstad, P G (2018) Powerful substances in tiny amounts: An interview study of psychedelic microdosing Nordic Studies on Alcohol and Drugs, 35(1), 39–51 https://doi org/10 1177/1455072517753339
Johnstad, P G (2020) A dangerous method? Psychedelic therapy at Modum Bad, Norway, 1961-76 History of Psychiatry, 31(2), 217–226 https://doi org/10 1177/0957154X19894537
Johnstad, P G (2021a) Day trip to hell: A mixed methods study of challenging psychedelic experiences Journal of Psychedelic Studies, 5(2), 114–127
https://doi.org/10.1556/2054.2021.00155
Johnstad, P G (2021b) Who is the typical psychedelics user? Methodological challenges for research in psychedelics use and its consequences Nordic Studies on Alcohol and Drugs, 38(1), 35–49. https://doi.org/10.1177/1455072520963787
Johnston, C B , Mangini, M , Grob, C , & Anderson, B (2023) The Safety and Efficacy of Psychedelic-Assisted Therapies for Older Adults: Knowns and Unknowns. The American Journal of Geriatric Psychiatry: Official Journal of the American Association for Geriatric Psychiatry, 31(1), 44–53. https://doi.org/10.1016/j.jagp.2022.08.007
Jones, G. M. (2023). Race and ethnicity moderate the associations between lifetime psychedelic use (MDMA/ecstasy and psilocybin) and major depressive episodes. Journal of Psychopharmacology, 37(1), 61–69 https://doi org/10 1177/02698811221127304
Jones, G. M., & Nock, M. K. (2022a). Exploring protective associations between the use of classic psychedelics and cocaine use disorder: A population-based survey study Scientific Reports, 12(1), 2574 https://doi org/10 1038/s41598-022-06580-2
Jones, G M , & Nock, M K (2022b) MDMA/ecstasy use and psilocybin use are associated with lowered odds of psychological distress and suicidal thoughts in a sample of US adults. Journal of Psychopharmacology (Oxford, England), 36(1), 46–56. https://doi org/10 1177/02698811211058923
Jones, G. M., & Nock, M. K. (2022c). Psilocybin use is associated with lowered odds of crime arrests in US adults: A replication and extension Journal of Psychopharmacology (Oxford, England), 36(1), 66–73 https://doi org/10 1177/02698811211058933
Jones, G. M., & Nock, M. K. (2022d). Race and ethnicity moderate the associations between lifetime psychedelic use (MDMA and psilocybin) and psychological distress and suicidality Scientific Reports, 12(1), 16976 https://doi org/10 1038/s41598-022-18645-3
Jones, J C , & Mohammed, A (2024) How Should Clinicians Share Decision Making With Patients Interested in Using Psychedelics to Feel Psychologically Safe? AMA Journal of Ethics, 26(11), 842–849 https://doi org/10 1001/amajethics 2024 842
Juillet, Y, Seurot, M , Gaux, J C , Fiessinger, J N , & Housset, E (1980) [Severe ischemia of the lower limbs after ingestion of LSD] Archives Des Maladies Du Coeur Et Des Vaisseaux, 73(11), 1359–1363
Kaelen, M , Giribaldi, B , Raine, J , Evans, L , Timmerman, C , Rodriguez, N , Roseman, L , Feilding, A , Nutt, D , & Carhart-Harris, R (2018) The hidden therapist: Evidence for a central role of music in psychedelic therapy. Psychopharmacology, 235(2), 505–519. https://doi.org/10.1007/s00213-017-4820-5
Kähönen, J. (2023). Psychedelic unselfing: Self-transcendence and change of values in psychedelic experiences. Frontiers in Psychology, 14, 1104627. https://doi.org/10.3389/fpsyg.2023.1104627
Kargbo, R. B. (2024). Innovative Psychedelic Therapies: Harnessing 5-MeO-DMT and DMT for Mental Health Treatment. ACS Medicinal Chemistry Letters, 15(11), 1812–1814. https://doi org/10 1021/acsmedchemlett 4c00490
Kelly, D. F., Heinzerling, K., Sharma, A., Gowrinathan, S., Sergi, K., & Mallari, R. J. (2023). Psychedelic-Assisted Therapy and Psychedelic Science: A Review and Perspective on Opportunities in Neurosurgery and Neuro-Oncology Neurosurgery, 92(4), 680–694
https://doi org/10 1227/neu 0000000000002275
Key Substance Use and Mental Health Indicators in the United States: Results from the 2023 National Survey on Drug Use and Health (n d -a)
Key Substance Use and Mental Health Indicators in the United States: Results from the 2023 National Survey on Drug Use and Health (n d -b)
Keyes, K M , & Patrick, M E (2023a) Hallucinogen use among young adults ages 19–30 in the United States: Changes from 2018 to 2021. Addiction, 118(12), 2449–2454. https://doi.org/10.1111/add.16259
Keyes, K. M., & Patrick, M. E. (2023b). Hallucinogen use among young adults ages 19–30 in the United States: Changes from 2018 to 2021. Addiction, 118(12), 2449–2454. https://doi org/10 1111/add 16259
Kilpatrick, Z. P., & Bard Ermentrout, G. (2012). Hallucinogen persisting perception disorder in neuronal networks with adaptation. Journal of Computational Neuroscience, 32(1), 25–53. https://doi org/10 1007/s10827-011-0335-y
Kious, B., Schwartz, Z., & Lewis, B. (2023). Should we be leery of being Leary? Concerns about psychedelic use by psychedelic researchers Journal of Psychopharmacology (Oxford, England), 37(1), 45–48 https://doi org/10 1177/02698811221133461
Kirkham, N , & Letheby, C (2024) Psychedelics and environmental virtues Philosophical Psychology, 37(2), 371–395 https://doi org/10 1080/09515089 2022 2057290
Kirlić, N., Lennard-Jones, M., Atli, M., Malievskaia, E., Modlin, N. L., Peck, S. K., Gaillard, A., Goodwin, G M , & Koelpin, D (2025) Compass Psychological Support Model for COMP360 Psilocybin Treatment of Serious Mental Health Conditions American Journal of Psychiatry, 182(1), 126–132 https://doi org/10 1176/appi ajp 20230884
Kishon, R , Modlin, N L , Cycowicz, Y M , Mourtada, H , Wilson, T, Williamson, V, Cleare, A , & Rucker, J (2024) A rapid narrative review of the clinical evolution of psychedelic treatment in clinical trials. Npj Mental Health Research, 3(1), 33. https://doi.org/10.1038/s44184-024-00068-9
Klaiber, A , Humbert-Droz, M , Ley, L , Schmid, Y, & Liechti, M E (n d ) Safety pharmacology of acute mescaline administration in healthy participants British Journal of Clinical Pharmacology, n/a(n/a). https://doi.org/10.1111/bcp.16349
Klock, J C , Boerner, U , & Becker, C E (1974) Coma, hyperthermia and bleeding associated with massive LSD overdose. A report of eight cases. The Western Journal of Medicine, 120(3), 183–188.
Kloft, L., Otgaar, H., Blokland, A., Toennes, S. W., & Ramaekers, J. G. (2022). Remembering Molly: Immediate and delayed false memory formation after acute MDMA exposure. European Neuropsychopharmacology: The Journal of the European College of Neuropsychopharmacology, 57, 59–68 https://doi org/10 1016/j euroneuro 2022 01 005
Klute, K. A., Lukas, L., Hwang, S., Gwon, Y., Krishnan, M., Grem, J., Hingorani, S., & Kellas, J. K (2024) Abstract C001: A pilot study of palliadelic treatment with psilocybin to reduce psychological distress and improve quality of life in patients with advanced pancreatic adenocarcinoma Cancer Research, 84(2 Supplement), C001 https://doi org/10 1158/1538-7445 PANCA2023-C001
Knuijver, T, Belgers, M , Markus, W, Verkes, R -J , Van Oosteren, T, & Schellekens, A (2018) Hallucinogen Persisting Perception Disorder After Ibogaine Treatment for Opioid Dependence. Journal of Clinical Psychopharmacology, 38(6), 646–648. https://doi org/10 1097/JCP0000000000000966
Knuijver, T., Schellekens, A., Belgers, M., Donders, R., van Oosteren, T., Kramers, K., & Verkes, R (2022) Safety of ibogaine administration in detoxification of opioid-dependent individuals: A descriptive open-label observational study Addiction (Abingdon, England), 117(1), 118–128 https://doi org/10 1111/add 15448
Kočárová, R , Horáček, J , & Carhart-Harris, R (2021) Does Psychedelic Therapy Have a Transdiagnostic Action and Prophylactic Potential? Frontiers in Psychiatry, 12, 661233 https://doi org/10 3389/fpsyt 2021 661233
Koenig, X , & Hilber, K (2015) The anti-addiction drug ibogaine and the heart: A delicate relation Molecules (Basel, Switzerland), 20(2), 2208–2228 https://doi org/10 3390/molecules20022208
Kohek, M , Ona, G , van Elk, M , Dos Santos, R G , Hallak, J E C , Alcázar-Córcoles, M Á , & Bouso, J C (2023) Ayahuasca and Public Health II: Health Status in a Large Sample of Ayahuasca-Ceremony Participants in the Netherlands. Journal of Psychoactive Drugs, 55(3), 247–258. https://doi.org/10.1080/02791072.2022.2077155
Koning, R. P. J., Benschop, A., Wijffels, C., & Noijen, J. (2021). Visitors of the Dutch drug checking services: Profile and drug use experience. The International Journal on Drug Policy, 95, 103293. https://doi.org/10.1016/j.drugpo.2021.103293
Kopra, E. I., Ferris, J. A., Rucker, J. J., McClure, B., Young, A. H., Copeland, C. S., & Winstock, A. R. (2022). Adverse experiences resulting in emergency medical treatment seeking following the use of lysergic acid diethylamide (LSD) Journal of Psychopharmacology, 36(8), 956–964 https://doi org/10 1177/02698811221099650
Kopra, E I , Ferris, J A , Winstock, A R , Young, A H , & Rucker, J J (n d ) Adverse experiences resulting in emergency medical treatment seeking following the use of magic mushrooms
Kopra, E I , Penttinen, J , Rucker, J J , & Copeland, C S (2025) Psychedelic-related deaths in England, Wales and Northern Ireland (1997–2022) Progress in Neuro-Psychopharmacology and Biological Psychiatry, 136, 111177 https://doi org/10 1016/j pnpbp 2024 111177
Korman, B A (2023) Lifetime classic psychedelic use is associated with greater psychological distress in unemployed job seekers Journal of Psychedelic Studies, 7(2), 90–99 https://doi.org/10.1556/2054.2023.00246
Korthuis, P T, Wilson‐Poe, A R , Black, J C , & Monte, A (2024) Commentary on Darke et al .: Expanded psychedelic access requires new safety monitoring systems. Addiction, 119(9), 1572–1574. https://doi.org/10.1111/add.16589
Koslowski, M., & Gasser, P. (2024). Guiding Through Challenging Psychedelic Experiences and “Bad Trips.” Current Topics in Behavioral Neurosciences.
https://doi org/10 1007/7854 2024 515
Krebs, T. S., & Johansen, P.-Ø. (2013). Psychedelics and Mental Health: A Population Study. PLoS ONE, 8(8), e63972. https://doi.org/10.1371/journal.pone.0063972
Kruger, D. J., Aday, J. S., Fields, C. W., Kolbman, N., Glynos, N., Barron, J., Herberholz, M., & Boehnke, K. F. (2024). Psychedelic Therapist Sexual Misconduct and Other Adverse Experiences Among a Sample of Naturalistic Psychedelic Users Psychedelic Medicine
https://doi org/10 1089/psymed 2024 0011
Kruger, D J , Barron, J , Herberholz, M , & Boehnke, K F (2023) Preferences and Support for Psychedelic Policies and Practices Among Those Using Psychedelics Journal of Psychoactive Drugs, 55(5), 650–659 https://doi org/10 1080/02791072 2023 2228784
Kruger, D J , Enghoff, O , Herberholz, M , Barron, J , & Boehnke, K F (2023) “How Do I Learn More About this?”: Utilization and Trust of Psychedelic Information Sources Among People Naturalistically Using Psychedelics Journal of Psychoactive Drugs, 55(5), 631–639 https://doi.org/10.1080/02791072.2023.2201263
Kruger, D J , Glynos, N G , Fields, C W, Herberholz, M , & Boehnke, K F (2023) An Assessment of Psychedelic Knowledge Among People Using Psychedelics Naturalistically. Journal of Psychoactive Drugs, 55(4), 420–424.
https://doi.org/10.1080/02791072.2022.2142709
Kuc, J., Kettner, H., Rosas, F., Erritzoe, D., Haijen, E., Kaelen, M., Nutt, D., & Carhart-Harris, R. L. (2022a). Psychedelic experience dose-dependently modulated by cannabis: Results of a prospective online survey Psychopharmacology, 239(5), 1425–1440
https://doi org/10 1007/s00213-021-05999-1
Kuc, J., Kettner, H., Rosas, F., Erritzoe, D., Haijen, E., Kaelen, M., Nutt, D., & Carhart-Harris, R. L (2022b) Psychedelic experience dose-dependently modulated by cannabis: Results of a prospective online survey Psychopharmacology, 239(5), 1425–1440 https://doi org/10 1007/s00213-021-05999-1
Kucsera, A , Suppes, T, & Haug, N A (2023) Psychologists’ and psychotherapists’ knowledge, attitudes, and clinical practices regarding the therapeutic use of psychedelics Clinical Psychology & Psychotherapy, 30(6), 1369–1379. https://doi.org/10.1002/cpp.2880
Kuiper, H , Alley, C , Harris, Z , Kuiper Rauch, C , Robbins, M , Rodriguez, P, Tomczak, P, Urrutia, J , & Magar, V (2024) Psychedelic public health: State of the field and implications for
equity Social Science & Medicine (1982), 357, 117134 https://doi.org/10.1016/j.socscimed.2024.117134
Kurtom, M , Henning, A , & Espiridion, E D (2019) Hallucinogen-persisting Perception Disorder in a 21-year-old Man. Cureus. https://doi.org/10.7759/cureus.4077
Kusumadewi, A F (2021) Case Report: Magic Mushroom (Psilocybe Cubensis) Intoxication Archives of The Medicine and Case Reports, 1(2), 31–34. https://doi.org/10.37275/amcr.v1i2.7
Kuypers, K P C (2020) The therapeutic potential of microdosing psychedelics in depression Therapeutic Advances in Psychopharmacology, 10, 2045125320950567 https://doi.org/10.1177/2045125320950567
Kuypers, K P C , & Ramaekers, J G (2005) Transient memory impairment after acute dose of 75mg 3.4-Methylene-dioxymethamphetamine. Journal of Psychopharmacology (Oxford, England), 19(6), 633–639. https://doi.org/10.1177/0269881105056670
Kuypers, K. P. C., & Ramaekers, J. G. (2007). Acute dose of MDMA (75 mg) impairs spatial memory for location but leaves contextual processing of visuospatial information unaffected. Psychopharmacology, 189(4), 557–563. https://doi.org/10.1007/s00213-006-0321-7
Kwaśny, A., Wilkowska, A., & Cubała, W. J. (2024). Short-term safety and tolerability profile of 5-methoxy-N,N-dimethyltryptamine in human subjects: A systematic review of clinical trials. Frontiers in Psychiatry, 15, 1477996 https://doi org/10 3389/fpsyt 2024 1477996
La Torre, J. T., Gallo, J., Mahammadli, M., Zalewa, D., & Williams, M. T. (2024). Experiences of psychedelic drug use among people with psychotic symptoms and disorders: Personal growth and mystical experiences Journal of Psychedelic Studies
https://doi org/10 1556/2054 2024 00348
Lacroix, E , Fatur, K , Hay, P, Touyz, S , & Keshen, A (2024) Psychedelics and the treatment of eating disorders: Considerations for future research and practice Journal of Eating Disorders, 12(1), 165 https://doi org/10 1186/s40337-024-01125-6
Lake, S , & Lucas, P (2023) The Canadian Psychedelic Survey: Characteristics, Patterns of Use, and Access in a Large Sample of People Who Use Psychedelic Drugs Psychedelic Medicine, 1(2), 98–110. https://doi.org/10.1089/psymed.2023.0002
Lake, S , & Lucas, P (2024a) Co-use of psychedelics with other substances: Findings from the global psychedelic survey Journal of Psychopharmacology, 02698811241292956 https://doi.org/10.1177/02698811241292956
Lake, S , & Lucas, P (2024b) The Global Psychedelic Survey: Consumer characteristics, patterns of use, and access in primarily anglophone regions around the world. The International Journal on Drug Policy, 130, 104507. https://doi.org/10.1016/j.drugpo.2024.104507
Lancelotta, R L , & Davis, A K (2020) Use of Benefit Enhancement Strategies among 5-Methoxy-N,N-Dimethyltryptamine (5-MeO-DMT) Users: Associations with Mystical, Challenging, and Enduring Effects. Journal of Psychoactive Drugs, 52(3), 273–281.
https://doi org/10 1080/02791072 2020 1737763
Langlitz, N. (2023). The making of a mushroom people: Toward a moral anthropology of psychedelics beyond hype and anti‐hype Anthropology Today, 39(3), 10–12
https://doi org/10 1111/1467-8322 12813
Lankenau, S. E., & Clatts, M. C. (2005). Patterns of Polydrug Use Among Ketamine Injectors in New York City Substance Use & Misuse, 40(9–10), 1381–1397
https://doi org/10 1081/JA-200066936
Larsen, J K (2016) Neurotoxicity and LSD treatment: A follow-up study of 151 patients in Denmark History of Psychiatry, 27(2), 172–189 https://doi org/10 1177/0957154X16629902
Lawn, W, Barratt, M , Williams, M , Horne, A , & Winstock, A (2014) The NBOMe hallucinogenic drug series: Patterns of use, characteristics of users and self-reported effects in a large international sample Journal of Psychopharmacology, 28(8), 780–788
https://doi org/10 1177/0269881114523866
Le Daré, B , Pelletier, R , Couette, A , Morel, I , & Gicquel, T (2022) Magic truffle intoxication: A case report Emergency Care Journal, 18(2) https://doi org/10 4081/ecj 2022 10347
Lea, T, Amada, N , & Jungaberle, H (2020) Psychedelic Microdosing: A Subreddit Analysis Journal of Psychoactive Drugs, 52(2), 101–112 https://doi.org/10.1080/02791072.2019.1683260
Lea, T, Amada, N , Jungaberle, H , Schecke, H , & Klein, M (2020a) Microdosing psychedelics: Motivations, subjective effects and harm reduction International Journal of Drug Policy, 75, 102600. https://doi.org/10.1016/j.drugpo.2019.11.008
Lea, T, Amada, N , Jungaberle, H , Schecke, H , Scherbaum, N , & Klein, M (2020b) Perceived outcomes of psychedelic microdosing as self-managed therapies for mental and substance use disorders. Psychopharmacology, 237(5), 1521–1532. https://doi.org/10.1007/s00213-020-05477-0
Lebedev, A. V., Acar, K., Garzón, B., Almeida, R., Råback, J., Åberg, A., Martinsson, S., Olsson, A., Louzolo, A., Pärnamets, P., Lövden, M., Atlas, L., Ingvar, M., & Petrovic, P. (2021). Psychedelic drug use and schizotypy in young adults Scientific Reports, 11(1), 15058 https://doi org/10 1038/s41598-021-94421-z
Ledwos, N , Rosenblat, J D , Blumberger, D M , Castle, D J , McIntyre, R S , Mulsant, B H , & Husain, M I (2022) A Critical Appraisal of Evidence on the Efficacy and Safety of Serotonergic Psychedelic Drugs as Emerging Antidepressants: Mind the Evidence Gap Journal of Clinical Psychopharmacology, 42(6), 581–588 https://doi org/10 1097/JCP0000000000001608
Lee McCabe, O , Savage, C , Kurland, A , & Unger, S (1972) Psychedelic (LSD) Therapy of Neurotic Disorders: Short-Term Effects. Journal of Psychedelic Drugs, 5(1), 18–28. https://doi.org/10.1080/02791072.1972.10471465
Leistenschneider, G., Majić, T., Reiche, S., & Riemer, T. G. (2024a). Neuropsychological profiles of patients suffering from hallucinogen persisting perception disorder (HPPD): A comparative analysis with psychedelic-using and non-using controls Scientific Reports, 14(1), 32159
https://doi org/10 1038/s41598-024-82216-x
Leistenschneider, G., Majić, T., Reiche, S., & Riemer, T. G. (2024b). Neuropsychological profiles of patients suffering from hallucinogen persisting perception disorder (HPPD): A comparative analysis with psychedelic-using and non-using controls Scientific Reports, 14(1), 32159
https://doi org/10 1038/s41598-024-82216-x
Leonard, J B , Anderson, B , & Klein-Schwartz, W (2018) Does getting high hurt?
Characterization of cases of LSD and psilocybin-containing mushroom exposures to national poison centers between 2000 and 2016 Journal of Psychopharmacology (Oxford, England), 32(12), 1286–1294. https://doi.org/10.1177/0269881118793086
Lerner, A G , Gelkopf, M , Oyffe, I , Finkel, B , Katz, S , Sigal, M , & Weizman, A (2000)
LSD-induced hallucinogen persisting perception disorder treatment with clonidine: An open pilot study. International Clinical Psychopharmacology, 15(1), 35–37. https://doi org/10 1097/00004850-200015010-00005
Lerner, A. G., Gelkopf, M., Skladman, I., Oyffe, I., Finkel, B., Sigal, M., & Weizman, A. (2002). Flashback and Hallucinogen Persisting Perception Disorder: Clinical aspects and pharmacological treatment approach The Israel Journal of Psychiatry and Related Sciences, 39(2), 92–99
Lerner, A G , Gelkopf, M , Skladman, I , Rudinski, D , Nachshon, H , & Bleich, A (2003)
Clonazepam treatment of lysergic acid diethylamide-induced hallucinogen persisting perception disorder with anxiety features International Clinical Psychopharmacology, 18(2), 101–105 https://doi org/10 1097/00004850-200303000-00007
Lerner, A G , & Goodman, C (2014) LSD Flashbacks – The Appearance of New Visual Imagery Not Experienced During Initial Intoxication: Two Case Reports Isr J Psychiatry Relat Sci, 51(4).
Lerner, A G , Rudinski, D , Bor, O , & Goodman, C (2014) Flashbacks and HPPD: A Clinical-oriented Concise Review. Isr J Psychiatry Relat Sci, 51(4).
Lev-Ran, S , Feingold, D , Frenkel, A , & Lerner, A G (2014) Clinical characteristics of individuals with schizophrenia and hallucinogen persisting perception disorder: A preliminary investigation. Journal of Dual Diagnosis, 10(2), 79–83. https://doi.org/10.1080/15504263.2014.906155
Lev-Ran, S , Feingold, D , Goodman, C , & Lerner, A G (2017) Comparing triggers to visual disturbances among individuals with positive vs negative experiences of hallucinogen-persisting perception disorder (HPPD) following LSD use: Comparing Triggers to HPPD Type I and II. The American Journal on Addictions, 26(6), 568–571 https://doi org/10 1111/ajad 12577
Lev‐Ran, S., Feingold, D., Rudinski, D., Katz, S., & Arturo, L. G. (2015). Schizophrenia and hallucinogen persisting perception disorder: A clinical investigation The American Journal on Addictions, 24(3), 197–199 https://doi org/10 1111/ajad 12204
Li, C., Tang, M. H., Chong, Y., Chan, T. Y., & Mak, T. W. (2019). Lysergic acid diethylamide–associated intoxication in Hong Kong: A case series Hong Kong Medical Journal, 25(4), 323–325 https://doi org/10 12809/hkmj197942
Liechti Lab | Department of Biomedicine | University of Basel (n d ) Retrieved January 23, 2025, from https://biomedizin unibas ch/en/research/research-groups/liechti-lab/?utm source=substack&ut m medium=email
Liester, M B (2014) A review of lysergic acid diethylamide (LSD) in the treatment of addictions: Historical perspectives and future prospects Current Drug Abuse Reviews, 7(3), 146–156 https://doi.org/10.2174/1874473708666150107120522
Lindahl, J R , Cooper, D J , Fisher, N E , Kirmayer, L J , & Britton, W B (2020) Progress or Pathology? Differential Diagnosis and Intervention Criteria for Meditation-Related Challenges: Perspectives From Buddhist Meditation Teachers and Practitioners. Frontiers in Psychology, 11. https://doi.org/10.3389/fpsyg.2020.01905
Litjens, R. P. W., Brunt, T. M., Alderliefste, G.-J., & Westerink, R. H. S. (2014). Hallucinogen persisting perception disorder and the serotonergic system: A comprehensive review including new MDMA-related clinical cases European Neuropsychopharmacology: The Journal of the European College of Neuropsychopharmacology, 24(8), 1309–1323 https://doi org/10 1016/j euroneuro 2014 05 008
Liu, Y, Lin, D , Wu, B , & Zhou, W (2016) Ketamine abuse potential and use disorder Brain Research Bulletin, 126(Pt 1), 68–73 https://doi org/10 1016/j brainresbull 2016 05 016
Livne, O , Shmulewitz, D , Walsh, C , & Hasin, D S (2022) Adolescent and adult time trends in US hallucinogen use, 2002–19: Any use, and use of ecstasy, LSD and PCP Addiction, 117(12), 3099–3109 https://doi org/10 1111/add 15987
Loizaga-Velder, A , & Loizaga Pazzi, A (2024) Traditional Medicine, Culture, and Psychedelic Science: New Pathways for Recovery From Substance Use Disorders Journal of Studies on Alcohol and Drugs, 85(5), 595–606. https://doi.org/10.15288/jsad.23-00011
Longitudinal experiences of Canadians receiving compassionate access to psilocybin-assisted psychotherapy (n d ) ResearchGate Retrieved January 14, 2025, from
https://wwwresearchgate net/publication/382313168 Longitudinal experiences of Canadians receiving compassionate access to psilocybin-assisted psychotherapy
Lowe, H , Toyang, N , Steele, B , Grant, J , Ali, A , Gordon, L , & Ngwa, W (2022) Psychedelics: Alternative and Potential Therapeutic Options for Treating Mood and Anxiety Disorders. Molecules, 27(8), 2520. https://doi.org/10.3390/molecules27082520
Luan, L. X., Eckernäs, E., Ashton, M., Rosas, F. E., Uthaug, M. V., Bartha, A., Jagger, S., Gascon-Perai, K., Gomes, L., Nutt, D. J., Erritzøe, D., Carhart-Harris, R. L., & Timmermann, C. (2024). Psychological and physiological effects of extended DMT. Journal of Psychopharmacology (Oxford, England), 38(1), 56–67
https://doi org/10 1177/02698811231196877
Lutfy, K , Pechnick, R N , & Darmani, N A (2023) Editorial: Pharmacology of new psychoactive substances Frontiers in Pharmacology, 14, 1208957
https://doi org/10 3389/fphar2023 1208957
Lutkajtis, A , & Evans, J (2023) Psychedelic integration challenges: Participant experiences after a psilocybin truffle retreat in the Netherlands Journal of Psychedelic Studies, 6(3), 211–221 https://doi org/10 1556/2054 2022 00232
MacConnel, H A (n d ) Rapid and sustained reduction of treatment-resistant PTSD symptoms after intravenous ketamine in a real-world, psychedelic paradigm
MacLean, K A , Johnson, M W, & Griffiths, R R (2011) Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness Journal of Psychopharmacology, 25(11), 1453–1461. https://doi.org/10.1177/0269881111420188
Makunts, T, Dahill, D , Jerome, L , de Boer, A , & Abagyan, R (2023) Concomitant medications associated with ischemic, hypertensive, and arrhythmic events in MDMA users in FDA adverse event reporting system. Frontiers in Psychiatry, 14, 1149766. https://doi.org/10.3389/fpsyt.2023.1149766
Makunts, T., Jerome, L., Abagyan, R., & de Boer, A. (2021). Reported Cases of Serotonin Syndrome in MDMA Users in FAERS Database. Frontiers in Psychiatry, 12, 824288. https://doi.org/10.3389/fpsyt.2021.824288
Malcolm, B., & Thomas, K. (2022). Serotonin toxicity of serotonergic psychedelics. Psychopharmacology, 239(6), 1881–1891. https://doi.org/10.1007/s00213-021-05876-x
Marazziti, D., Weiss, F., Gurrieri, R., Russomanno, G., Gambini, M., Magnesa, A., Coccoglioniti, A., & Perugi, G. (2024). Evaluating the value and risks of psychedelics for psychiatric medicine: A clinical perspective Expert Review of Neurotherapeutics, 1–14 https://doi org/10 1080/14737175 2024 2445016
Marchi, M , Farina, R , Rachedi, K , Laonigro, F, Žuljević, M F, Pingani, L , Ferrari, S , Somers, M., Boks, M. P. M., & Galeazzi, G. M. (2024). Psychedelics as an intervention for psychological, existential distress in terminally ill patients: A systematic review and network meta-analysis. Journal of Psychopharmacology (Oxford, England), 2698811241303594 https://doi org/10 1177/02698811241303594
Marcus, O (2023) ‘Everybody’s creating it along the way’: Ethical tensions among globalized ayahuasca shamanisms and therapeutic integration practices Interdisciplinary Science Reviews, 48(5), 712–731 https://doi org/10 1080/03080188 2022 2075201
Marrocu, A , Kettner, H , Weiss, B , Zeifman, R J , Erritzoe, D , & Carhart-Harris, R L (n d ) Psychiatric risks for worsened mental health after psychedelic use
Martin, J M , & Sterzer, P (2022) How Level is the “Cognitive Playing Field”?: Context Shapes Alterations in Self-Conception During the Psychedelic Experience Philosophy and the Mind Sciences, 3 https://doi org/10 33735/phimisci 2022 9326
Martinotti, G , Santacroce, R , Pettorruso, M , Montemitro, C , Spano, M , Lorusso, M , Di Giannantonio, M , & Lerner, A (2018) Hallucinogen Persisting Perception Disorder: Etiology, Clinical Features, and Therapeutic Perspectives Brain Sciences, 8(3), 47 https://doi.org/10.3390/brainsci8030047
Martins, D , Gil-Martins, E , Cagide, F, Da Fonseca, C , Benfeito, S , Fernandes, C , Chavarria, D., Remião, F., Silva, R., & Borges, F. (2023). Unraveling the In Vitro Toxicity Profile of Psychedelic 2C Phenethylamines and Their N-Benzylphenethylamine (NBOMe) Analogues. Pharmaceuticals, 16(8), 1158. https://doi.org/10.3390/ph16081158
Mash, D. C., Kovera, C. A., Pablo, J., Tyndale, R. F., Ervin, F. D., Williams, I. C., Singleton, E. G., & Mayor, M. (2000). Ibogaine: Complex pharmacokinetics, concerns for safety, and preliminary efficacy measures Annals of the New York Academy of Sciences, 914, 394–401 https://doi org/10 1111/j 1749-6632 2000 tb05213 x
Matzopoulos, R , Morlock, R , Morlock, A , Lerer, B , & Lerer, L (2022) Psychedelic Mushrooms in the USA: Knowledge, Patterns of Use, and Association With Health Outcomes Frontiers in Psychiatry, 12 https://doi org/10 3389/fpsyt 2021 780696
Maxwell, J C (2005) Party Drugs: Properties, Prevalence, Patterns, and Problems Substance Use & Misuse, 40(9–10), 1203–1240 https://doi org/10 1081/JA-200066736
McAlpine, R G , Sacchet, M D , Simonsson, O , Khan, M , Krajnovic, K , Morometescu, L , & Kamboj, S K (2024) Development of a digital intervention for psychedelic preparation (DIPP) Scientific Reports, 14(1), 4072 https://doi org/10 1038/s41598-024-54642-4
McClintock, R L , Watts, D J , & Melanson, S (2008) Unrecognized magic mushroom abuse in a 28-year-old man The American Journal of Emergency Medicine, 26(8), 972 e3-4 https://doi org/10 1016/j ajem 2008 01 058
McConnell, A , He, W, McConnell, H , & Sowman, P F (2023) Associations between Hallucinogen Persisting Perception Disorder (HPPD) and non-visual perceptual disturbances. PsyArXiv. https://doi.org/10.31234/osf.io/xeg96
McGovern, H. T., Grimmer, H. J., Doss, M. K., Hutchinson, B. T., Timmermann, C., Lyon, A., Corlett, P. R., & Laukkonen, R. E. (2024). An Integrated theory of false insights and beliefs under psychedelics Communications Psychology, 2(1), 1–13
https://doi org/10 1038/s44271-024-00120-6
McGuire, A. L., Cohen, I. G., Sisti, D., Baggott, M., Celidwen, Y., Devenot, N., Gracias, S., Grob, C , Harvey, I , Kious, B , Marks, M , Mithoefer, M , Nielson, E , Öngür, D , Pallas, A , Peterson, A , Schenberg, E E , Summergrad, P, Waters, B , Yaden, D B (2024) Developing an Ethics and Policy Framework for Psychedelic Clinical Care: A Consensus Statement JAMA Network Open, 7(6), e2414650. https://doi.org/10.1001/jamanetworkopen.2024.14650
McIntyre, R S , Kwan, A T H , Mansur, R B , Oliveira-Maia, A J , Teopiz, K M , Maletic, V, Suppes, T, Stahl, S M , & Rosenblat, J D (2025) Psychedelics for the Treatment of Psychiatric Disorders: Interpreting and Translating Available Evidence and Guidance for Future Research. American Journal of Psychiatry, 182(1), 21–32. https://doi org/10 1176/appi ajp 20230902
McNamee, S., Devenot, N., & Buisson, M. (2023). Studying Harms Is Key to Improving Psychedelic-Assisted Therapy-Participants Call for Changes to Research Landscape JAMA Psychiatry, 80(5), 411–412 https://doi org/10 1001/jamapsychiatry2023 0099
McWilliams, S. A., & Tuttle, R. J. (1973). Long-term psychological effects of LSD. Psychological Bulletin, 79(6), 341–351 https://doi org/10 1037/h0034411
Mehtani, N. J., Johnson, M. O., Hendricks, P. S., Mitchell, J., & Anderson, B. T. (2024). Psilocybin-assisted therapy and HIV-related shame Scientific Reports, 14(1), 17919 https://doi org/10 1038/s41598-024-68908-4
Menon, V, Ramamurthy, P, Venu, S , & Andrade, C (2024) Randomized Controlled Trials of Psilocybin-Assisted Therapy in the Treatment of Major Depressive Disorder: Systematic Review and Meta-Analysis Acta Psychiatrica Scandinavica https://doi org/10 1111/acps 13778
Meyer, T D , Ibrahim, M , Vale, L N , & Soares, J C (2025) Psychedelic use and bipolar disorder – An investigation of recreational use and its impact on mental health Journal of Affective Disorders, 373, 505–511 https://doi org/10 1016/j jad 2024 12 044
Mian, M N , Dinh, M T, Coker, A R , Mitchell, J M , & Anderson, B T (2025) Psychedelic Regulation Beyond the Controlled Substances Act: A Three-Dimensional Framework for Characterizing Policy Options. American Journal of Psychiatry, 182(1), 6–9. https://doi.org/10.1176/appi.ajp.20230787
Miceli McMillan, R (2022) Psychedelic injustice: Should bioethics tune in to the voices of psychedelic-using communities? Medical Humanities, 48(3), 269–272. https://doi.org/10.1136/medhum-2021-012299
Miller, E., Bojovic, V., Maddren, O., Rao, P., Adesina, D., Petrenko, A., & Ponton, R. (2024). Psychedelic Drug Microdosing Practices: A Qualitative Online Exploration. Journal of Psychoactive Drugs, 1–10 https://doi org/10 1080/02791072 2024 2304554
Miller, P. L., Gay, G. R., Ferris, K. C., & Anderson, S. (1992). Treatment of acute, adverse psychedelic reactions: “I’ve tripped and I can’t get down.” Journal of Psychoactive Drugs, 24(3), 277–279 https://doi org/10 1080/02791072 1992 10471649
Millière, R., Carhart-Harris, R. L., Roseman, L., Trautwein, F.-M., & Berkovich-Ohana, A. (2018). Psychedelics, Meditation, and Self-Consciousness Frontiers in Psychology, 9, 1475 https://doi org/10 3389/fpsyg 2018 01475
Mitchell, J M , Bogenschutz, M , Lilienstein, A , Harrison, C , Kleiman, S , Parker-Guilbert, K , Ot’alora G , M , Garas, W, Paleos, C , Gorman, I , Nicholas, C , Mithoefer, M , Carlin, S , Poulter, B , Mithoefer, A , Quevedo, S , Wells, G , Klaire, S S , van der Kolk, B , Doblin, R (2021) MDMA-assisted therapy for severe PTSD: A randomized, double-blind, placebo-controlled phase 3 study. Nature Medicine, 27(6), 1025–1033. https://doi.org/10.1038/s41591-021-01336-3
Mithoefer, M. C., Wagner, M. T., Mithoefer, A. T., Jerome, L., Martin, S. F., Yazar-Klosinski, B., Michel, Y., Brewerton, T. D., & Doblin, R. (2013). Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: A prospective long-term follow-up study Journal of Psychopharmacology (Oxford, England), 27(1), 28–39
https://doi org/10 1177/0269881112456611
Modak, T, Bhad, R , & Rao, R (2019) A rare case of physical dependence with psychedelic LSD - A case report Journal of Substance Use, 24(4), 347–349
https://doi org/10 1080/14659891 2019 1581286
Modlin, N , Creed, M , Sarang, M , Maggio, C , Rucker, J , & Williamson, V (2024)
Trauma-Informed Care in Psychedelic Therapy Research: A Qualitative Literature Review of Evidence-Based Psychotherapy Interventions in PTSD and Psychedelic Therapy Across Conditions. Neuropsychiatric Disease and Treatment, Volume 20, 109–135.
https://doi org/10 2147/NDTS432537
Modlin, N. L., McPhee, T., Zazon, N., Sarang, M., Hignett, R., Pick, S., Cleare, A., Williamson, V, & Rucker, J (2024) Participants’ Experience of Psychedelic Integration Groups and Processes: A Qualitative Thematic Analysis Psychedelic Medicine
https://doi org/10 1089/psymed 2024 0027
Modlin, N L , Miller, T M , Rucker, J J , Kirlic, N , Lennard-Jones, M , Schlosser, D , & Aaronson, S. T. (2023). Optimizing outcomes in psilocybin therapy: Considerations in participant evaluation and preparation. Journal of Affective Disorders, 326, 18–25.
https://doi org/10 1016/j jad 2023 01 077
Morgan, C. J. A., Muetzelfeldt, L., Muetzelfeldt, M., Nutt, D. J., & Curran, H. V. (2010). Harms associated with psychoactive substances: Findings of the UK National Drug Survey Journal of Psychopharmacology (Oxford, England), 24(2), 147–153
https://doi org/10 1177/0269881109106915
Móró, L , & Rácz, J (2013) Online drug user-led harm reduction in Hungary: A review of “Daath ” Harm Reduction Journal, 10(1), 18 https://doi org/10 1186/1477-7517-10-18
Móró, L , Simon, K , Bárd, I , & Rácz, J (2011) Voice of the Psychonauts: Coping, Life Purpose, and Spirituality in Psychedelic Drug Users Journal of Psychoactive Drugs, 43(3), 188–198
https://doi org/10 1080/02791072 2011 605661
Morton, E , Sakai, K , Ashtari, A , Pleet, M , Michalak, E E , & Woolley, J (2023) Risks and benefits of psilocybin use in people with bipolar disorder: An international web-based survey on experiences of ‘magic mushroom’ consumption Journal of Psychopharmacology, 37(1), 49–60
https://doi.org/10.1177/02698811221131997
Müller, F, Kraus, E , Holze, F, Becker, A , Ley, L , Schmid, Y, Vizeli, P, Liechti, M E , & Borgwardt, S. (2022). Flashback phenomena after administration of LSD and psilocybin in controlled studies with healthy participants. Psychopharmacology, 239(6), 1933–1943.
https://doi.org/10.1007/s00213-022-06066-z
Müller, F., Mühlhauser, M., Holze, F., Lang, U. E., Walter, M., Liechti, M. E., & Borgwardt, S. (2020). Treatment of a Complex Personality Disorder Using Repeated Doses of LSD A Case Report on Significant Improvements in the Absence of Acute Drug Effects Frontiers in Psychiatry, 11, 573953 https://doi org/10 3389/fpsyt 2020 573953
Müller, K , Püschel, K , & Iwersen-Bergmann, S (2013) [Suicide under the influence of “magic mushrooms”] Archiv Fur Kriminologie, 231(5–6), 193–198
Murphy, R. J., Muthukumaraswamy, S., & de Wit, H. (2024). Microdosing Psychedelics: Current Evidence From Controlled Studies Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, 9(5), 500–511 https://doi org/10 1016/j bpsc 2024 01 002
Murray, C H , Tare, I , Perry, C M , Malina, M , Lee, R , & De Wit, H (2022) Low doses of LSD reduce broadband oscillatory power and modulate event-related potentials in healthy adults Psychopharmacology, 239(6), 1735–1747 https://doi org/10 1007/s00213-021-05991-9
Murrough, J W, Burdick, K E , Levitch, C F, Perez, A M , Brallier, J W, Chang, L C , Foulkes, A , Charney, D S , Mathew, S J , & Iosifescu, D V (2015) Neurocognitive effects of ketamine and association with antidepressant response in individuals with treatment-resistant
depression: A randomized controlled trial Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 40(5), 1084–1090. https://doi.org/10.1038/npp.2014.298
Muthukumaraswamy, S. D., Carhart-Harris, R. L., Moran, R. J., Brookes, M. J., Williams, T. M., Errtizoe, D., Sessa, B., Papadopoulos, A., Bolstridge, M., Singh, K. D., Feilding, A., Friston, K. J , & Nutt, D J (2013) Broadband Cortical Desynchronization Underlies the Human Psychedelic State The Journal of Neuroscience, 33(38), 15171–15183 https://doi org/10 1523/JNEUROSCI 2063-13 2013
Muthukumaraswamy, S , Forsyth, A , & Sumner, R L (2022) The challenges ahead for psychedelic “medicine ” The Australian and New Zealand Journal of Psychiatry, 56(11), 1378–1383 https://doi org/10 1177/00048674221081763
Naudet, F, Fried, E I , Cosgrove, L , Turner, E , Braillon, A , & Cristea, I A (2022) Psychedelic drugs: More emphasis on safety issues Nature, 611(7936), 449–449 https://doi org/10 1038/d41586-022-03680-x
Nayak, S M , Gukasyan, N , Barrett, F S , Erowid, E , Erowid, F, & Griffiths, R R (2021)
Classic Psychedelic Coadministration with Lithium, but Not Lamotrigine, is Associated with Seizures: An Analysis of Online Psychedelic Experience Reports. Pharmacopsychiatry, 54(5), 240–245. https://doi.org/10.1055/a-1524-2794
Nayak, S. M., Jackson, H., Sepeda, N. D., Mathai, D. S., So, S., Yaffe, A., Zaki, H., Brasher, T. J., Lowe, M. X., Jolly, D. R. P., Barrett, F. S., Griffiths, R. R., Strickland, J. C., Johnson, M. W., Jackson, H., & Garcia-Romeu, A. (2023). Naturalistic psilocybin use is associated with persisting improvements in mental health and wellbeing: Results from a prospective, longitudinal survey Frontiers in Psychiatry, 14 https://doi org/10 3389/fpsyt 2023 1199642
Nayak, S M , White, S , Hilbert, S , Lowe, M X , Jackson, H , Griffiths, R R , Garcia-Romeu, A , & Yaden, D B (2023) Naturalistic Psilocybin Use Increases Mind Perception but not Atheist-Believer status: A Prospective Longitudinal Study PsyArXiv https://doi org/10 31234/osf io/auycp
Neicun, J , Yang, J C , Shih, H , Nadella, P, Kessel, R van, Negri, A , Czabanowska, K , Brayne, C , & Roman-Urrestarazu, A (2020) Lifetime prevalence of novel psychoactive substances use among adults in the USA: Sociodemographic, mental health and illicit drug use correlates. Evidence from a population-based survey 2007–2014. PLOS ONE, 15(10), e0241056 https://doi org/10 1371/journal pone 0241056
Neitzke-Spruill, L. (2022). Psychedelics and Desistance From Crime: Lessons From the Concord Prison Experiment Journal of Humanistic Psychology, 00221678221136233 https://doi org/10 1177/00221678221136233
Neitzke-Spruill, L , Beit, C , Robinson, J , Blevins, K , Reynolds, J , Evans, N G , & McGuire, A L. (2024). A Transformative Trip? Experiences of Psychedelic Use. Neuroethics, 17(2), 33. https://doi.org/10.1007/s12152-024-09567-0
Neitzke-Spruill, L., Devenot, N., Sisti, D., Averill, L. A., & McGuire, A. L. (2024).
Bio-Psycho-Spiritual Perspectives on Psychedelics: Clinical and Ethical Implications. Perspectives in Biology and Medicine, 67(1), 117–142
Nesvåg, R., Bramness, J. G., & Ystrom, E. (2015). The link between use of psychedelic drugs and mental health problems. Journal of Psychopharmacology, 29(9), 1035–1040.
https://doi org/10 1177/0269881115596156
Neubert, J. J., Anderson, K., & Mason, N. L. (2024). Psychedelic intimacy: Altered states of consciousness in romantic relationships Journal of Psychedelic Studies
https://doi org/10 1556/2054 2024 00319
Neumann, J , Dhein, S , Kirchhefer, U , Hofmann, B , & Gergs, U (2024) Effects of hallucinogenic drugs on the human heart Frontiers in Pharmacology, 15, 1334218
https://doi org/10 3389/fphar2024 1334218
Neven, A , & Blom, J D (2014) Synesthesieën in het kader van de persisterende waarnemingsstoornis door hallucinogenen na gebruik van lsd TIJDSCHRIFT VOOR
PSYCHIATRIE
New insights into the clinical and nonclinical effects of psychedelic substances: An integrative review (n d ) ResearchGate Retrieved January 14, 2025, from https://www.researchgate.net/publication/351474838 New insights into the clinical and nonc linical effects of psychedelic substances an integrative review
Nichols, D E , & Barker, E L (2016) Psychedelics Pharmacological Reviews, 68(2), 264–355 https://doi.org/10.1124/pr.115.011478
Nogueira, M , García-Hernández, S , Roberto, G S , & Marques, L Z (2025) Psilocybin Mushrooms and Public Health in Brazil: Insights from a Retrospective Analysis of Adverse Events and Their Implications for Regulatory Discussions. International Journal of Medicinal Mushrooms, 27(2). https://doi.org/10.1615/IntJMedMushrooms.2024057053
Noorani, T. (2021). Containment Matters: Set and Setting in Contemporary Psychedelic Psychiatry. Philosophy, Psychiatry, & Psychology, 28(3), 201–216.
https://doi org/10 1353/ppp 2021 0032
Nour, M. M., Evans, L., & Carhart-Harris, R. L. (2017). Psychedelics, Personality and Political Perspectives Journal of Psychoactive Drugs, 49(3), 182–191
https://doi org/10 1080/02791072 2017 1312643
Noushad, F (2015) 25 years of Hallucinogen Persisting Perception Disorder- A diagnostic challenge. 8(1).
Novak, S J (1997) LSD before Leary Sidney Cohen’s critique of 1950s psychedelic drug research. Isis; an International Review Devoted to the History of Science and Its Cultural Influences, 88(1), 87–110. https://doi.org/10.1086/383628
Nutt, D., & Carhart-Harris, R. (2021). The Current Status of Psychedelics in Psychiatry. JAMA Psychiatry, 78(2), 121–122. https://doi.org/10.1001/jamapsychiatry.2020.2171
Nutting, S , Bruinsma, T, Anderson, M , & Jolly, T (2021) Psychotic and Still Tripping Hallucinogen Persisting Perception Disorder and First Break Psychosis in an Adolescent. International Journal of Mental Health and Addiction, 19(6), 2440–2442. https://doi org/10 1007/s11469-020-00338-5
O’Donnell, K. C., Grigsby, J., & Grob, C. S. (2025a). Healing, Harms, and Humility: Expanding the Scope of Psychedelic-Assisted Psychotherapy Research American Journal of Psychiatry, 182(1), 13–16 https://doi org/10 1176/appi ajp 20230785
O’Donnell, K. C., Grigsby, J., & Grob, C. S. (2025b). Healing, Harms, and Humility: Expanding the Scope of Psychedelic-Assisted Psychotherapy Research American Journal of Psychiatry, 182(1), 13–16 https://doi org/10 1176/appi ajp 20230785
Okano, L , Jones, G , Deyo, B , Brandenburg, A , & Hale, W (2022) Therapeutic setting as an essential component of psychedelic research methodology: Reporting recommendations emerging from clinical trials of 3,4-methylenedioxymethamphetamine for post-traumatic stress disorder. Frontiers in Psychiatry, 13, 965641. https://doi.org/10.3389/fpsyt.2022.965641
Oliver, D (n d -a) Psilocybin Newspaper Coverage – Sentiment and Frequency (1989-2020)
Oliver, D (n d -b) Psilocybin Newspaper Coverage – Sentiment and Frequency (1989-2020)
Olson, D. E. (2022). Biochemical Mechanisms Underlying Psychedelic-Induced Neuroplasticity. Biochemistry, 61(3), 127–136 https://doi org/10 1021/acs biochem 1c00812
Ona, G. (2018). Inside bad trips: Exploring extra-pharmacological factors. Journal of Psychedelic Studies, 2(1), 53–60 https://doi org/10 1556/2054 2018 001
Orłowski, P., Ruban, A., Szczypiński, J., Hobot, J., Bielecki, M., & Bola, M. (2022). Naturalistic use of psychedelics is related to emotional reactivity and self-consciousness: The mediating role of ego-dissolution and mystical experiences Journal of Psychopharmacology, 36(8), 987–1000 https://doi org/10 1177/02698811221089034
Orsolini, L , Papanti, G D , De Berardis, D , Guirguis, A , Corkery, J M , & Schifano, F (2017) The “Endless Trip” among the NPS Users: Psychopathology and Psychopharmacology in the
Hallucinogen-Persisting Perception Disorder A Systematic Review Frontiers in Psychiatry, 8, 240. https://doi.org/10.3389/fpsyt.2017.00240
Ortiz Bernal, A M , Raison, C L , Lancelotta, R L , & Davis, A K (2022) Reactivations after 5-methoxy-N,N-dimethyltryptamine use in naturalistic settings: An initial exploratory analysis of the phenomenon’s predictors and its emotional valence. Frontiers in Psychiatry, 13, 1049643. https://doi org/10 3389/fpsyt 2022 1049643
Pagni, B. A., Zeifman, R. J., Mennenga, S. E., Carrithers, B. M., Goldway, N., Bhatt, S., O’Donnell, K. C., Ross, S., & Bogenschutz, M. P. (2025). Multidimensional Personality Changes Following Psilocybin-Assisted Therapy in Patients With Alcohol Use Disorder: Results From a Double-Blind, Placebo-Controlled Clinical Trial American Journal of Psychiatry, 182(1), 114–125 https://doi org/10 1176/appi ajp 20230887
Palamar, J J , & Acosta, P (2020) A qualitative descriptive analysis of effects of psychedelic phenethylamines and tryptamines Human Psychopharmacology: Clinical and Experimental, 35(1), e2719 https://doi org/10 1002/hup 2719
Palamar, J J , & Le, A (2018) Trends in DMT and other tryptamine use among young adults in the United States The American Journal on Addictions, 27(7), 578–585 https://doi.org/10.1111/ajad.12803
Palamar, J J , Martins, S S , Su, M K , & Ompad, D C (2015) Self-reported use of novel psychoactive substances in a US nationally representative survey: Prevalence, correlates, and a call for new survey methods to prevent underreporting. Drug and Alcohol Dependence, 156, 112–119. https://doi.org/10.1016/j.drugalcdep.2015.08.028
Palamar, J. J., Rutherford, C., & Keyes, K. M. (2025a). Diversion of Undistributed Pharmaceutical Ketamine in the US. JAMA, 333(3), 252–254.
https://doi org/10 1001/jama 2024 23014
Palamar, J. J., Rutherford, C., & Keyes, K. M. (2025b). Diversion of Undistributed Pharmaceutical Ketamine in the US JAMA, 333(3), 252–254
https://doi org/10 1001/jama 2024 23014
Palamar, J. J., Rutherford, C., Le, A., & Keyes, K. M. (2024). Seasonal Variation of Use of Common Psychedelics and Party Drugs Among Nightclub/Festival Attendees in New York City Journal of Psychoactive Drugs, 56(4), 467–474
https://doi org/10 1080/02791072 2023 2240322
Palamar, J J , Wilkinson, S T, Carr, T H , Rutherford, C , & Cottler, L B (2023) Trends in Illicit Ketamine Seizures in the US From 2017 to 2022 JAMA Psychiatry, 80(7), 750–751
https://doi.org/10.1001/jamapsychiatry.2023.1423
Páleníček, T, Fujáková, M , Brunovský, M , Horáček, J , Gorman, I , Balíková, M , Rambousek, L , Syslová, K , Kačer, P, Zach, P, Bubeníková-Valešová, V, Tylš, F, Kubešová, A ,
Puskarčíková, J , & Höschl, C (2013) Behavioral, neurochemical and pharmaco-EEG profiles of the psychedelic drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in rats. Psychopharmacology, 225(1), 75–93. https://doi.org/10.1007/s00213-012-2797-7
Palitsky, R., Canby, N. K., Van Dam, N. T., Levin-Aspenson, H. F., Kaplan, D. M., Maples-Keller, J., Raison, C. L., Grant, G. H., Dunlop, B. W., & Britton, W. B. (n.d.). Leveraging meditation research for the study of psychedelic-related adverse effects International Review of Psychiatry, 0(0), 1–15 https://doi org/10 1080/09540261 2024 2420745
Palitsky, R., Kaplan, D. M., Perna, J., Bosshardt, Z., Maples-Keller, J. L., Levin-Aspenson, H. F., Zarrabi, A J , Peacock, C , Mletzko, T, Rothbaum, B O , Raison, C L , Grant, G H , & Dunlop, B W (n d ) A framework for assessment of adverse events occurring in psychedelic-assisted therapies
Palitsky, R , Kaplan, D M , Perna, J , Bosshardt, Z , Maples-Keller, J L , Levin-Aspenson, H F, Zarrabi, A J , Peacock, C , Mletzko, T, Rothbaum, B O , Raison, C L , Grant, G H , & Dunlop, B W (2024) A framework for assessment of adverse events occurring in psychedelic-assisted therapies. Journal of Psychopharmacology, 38(8), 690–700. https://doi.org/10.1177/02698811241265756
Palmer, M., & Maynard, O. M. (2022). Are you tripping comfortably? Investigating the relationship between harm reduction and the psychedelic experience. Harm Reduction Journal, 19(1), 81 https://doi org/10 1186/s12954-022-00662-0
Pantoni, M. M., Kim, J. L., Van Alstyne, K. R., & Anagnostaras, S. G. (2022). MDMA and memory, addiction, and depression: Dose-effect analysis. Psychopharmacology, 239(3), 935–949 https://doi org/10 1007/s00213-022-06086-9
Papaseit, E., Pérez-Mañá, C., Mateus, J.-A., Pujadas, M., Fonseca, F., Torrens, M., Olesti, E., de la Torre, R , & Farré, M (2016) Human Pharmacology of Mephedrone in Comparison with MDMA Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 41(11), 2704–2713 https://doi org/10 1038/npp 2016 75
Papaseit, E , Torrens, M , Pérez-Mañá, C , Muga, R , & Farré, M (2018) Key interindividual determinants in MDMA pharmacodynamics Expert Opinion on Drug Metabolism & Toxicology, 14(2), 183–195 https://doi org/10 1080/17425255 2018 1424832
Parrott, A C (2014) The Potential Dangers of Using MDMA for Psychotherapy Journal of Psychoactive Drugs, 46(1), 37–43 https://doi org/10 1080/02791072 2014 873690
Pashdag, J (2024) Non-hallucinogenic psychedelic psychotherapy: Decreasing risk and increasing access, or missing the point? Journal of Psychedelic Studies https://doi.org/10.1556/2054.2024.00385
Passie, T, & Brandt, S D (2018) Self-Experiments with Psychoactive Substances: A Historical Perspective. Handbook of Experimental Pharmacology, 252, 69–110.
https://doi.org/10.1007/164 2018 177
Paul, M. J., Chisolm, M. S., Johnson, M. W., Vandrey, R. G., & Dredze, M. (2016). Assessing the Validity of Online Drug Forums as a Source for Estimating Demographic and Temporal Trends in Drug Use Journal of Addiction Medicine, 10(5), 324
https://doi org/10 1097/ADM 0000000000000238
(PDF) Investigating LSA - a ‘legal high’ analogue to LSD, frequently used in the digital realm with relatively unknown effects (2024) ResearchGate
https://doi org/10 1192/j eurpsy2024 1150
(PDF) Using thematic analysis in psychology (2024) ResearchGate
https://doi org/10 1191/1478088706qp063oa
Peden, N R , Macaulay, K E C , Bissett, A F, Crooks, J , & Pelosi, A J (1981) Clinical toxicology of ‘magic mushroom’ ingestion Postgraduate Medical Journal, 57(671), 543–545
https://doi org/10 1136/pgmj 57 671 543
Pedersen, M M , & Steglich-Petersen, A (n d ) On the social epistemology of psychedelic experience Philosophical Psychology, 0(0), 1–19
https://doi org/10 1080/09515089 2024 2369685
Pestana, J , Beccaria, F, & Petrilli, E (2021) Psychedelic substance use in the Reddit psychonaut community A qualitative study on motives and modalities Drugs and Alcohol Today, 21(2), 112–123. https://doi.org/10.1108/DAT-03-2020-0016
Petersen, M , Garg, U , & Ketha, H (2020) Chapter 16 Hallucinogens Psychedelics and dissociative drugs In H Ketha & U Garg (Eds ), Toxicology Cases for the Clinical and Forensic Laboratory (pp. 295–303). Academic Press.
https://doi.org/10.1016/B978-0-12-815846-3.00016-8
Peterson, A., Largent, E. A., Lynch, H. F., Karlawish, J., & Sisti, D. (2023). Journeying to Ixtlan: Ethics of Psychedelic Medicine and Research for Alzheimer’s Disease and Related Dementias. AJOB Neuroscience, 14(2), 107–123. https://doi.org/10.1080/21507740.2022.2148771
Petranker, R., Anderson, T., & Farb, N. (2020). Psychedelic Research and the Need for Transparency: Polishing Alice’s Looking Glass. Frontiers in Psychology, 11, 1681.
https://doi org/10 3389/fpsyg 2020 01681
Petranker, R., Anderson, T., Maier, L. J., Barratt, M. J., Ferris, J. A., & Winstock, A. R. (2022). Microdosing psychedelics: Subjective benefits and challenges, substance testing behavior, and the relevance of intention Journal of Psychopharmacology, 36(1), 85–96
https://doi org/10 1177/0269881120953994
Petranker, R , Kim, J , & Anderson, T (2020) Microdosing as a response to the meaning crisis PsyArXiv. https://doi.org/10.31234/osf.io/2jnkf
Pflieger, C (2005) Les flashbacks induits par les psychodysleptiques hallucinogènes Psychotropes, 11(1), 9. https://doi.org/10.3917/psyt.111.0009
Piercey, C J , Gray, B , Sung, A , Henry, D , & Karoly, H C (2024) Protective Behavioral Strategies for Psychedelic Use: A Mini Review of the Evidence. Psychedelic Medicine, 2(4), 234–242. https://doi.org/10.1089/psymed.2023.0052
Pierrot, M , Josse, P, Raspiller, M F, Goulmy, M , Rambourg, M O , Manel, J , & Lambert, H (2000). [Intoxications by hallucinogenic mushrooms]. Annales De Medecine Interne, 151 Suppl B, B16-19.
Pilecki, B., Luoma, J. B., Bathje, G. J., Rhea, J., & Narloch, V. F. (2021). Ethical and legal issues in psychedelic harm reduction and integration therapy. Harm Reduction Journal, 18(1), 40. https://doi org/10 1186/s12954-021-00489-1
Pleet, M. M., White, J., Zamaria, J. A., & Yehuda, R. (2023). Reducing the Harms of Nonclinical Psychedelics Use Through a Peer-Support Telephone Helpline. Psychedelic Medicine, 1(2), 69–73 https://doi org/10 1089/psymed 2022 0017
Pokorny, T., Preller, K. H., Kometer, M., Dziobek, I., & Vollenweider, F. X. (2017). Effect of Psilocybin on Empathy and Moral Decision-Making International Journal of Neuropsychopharmacology, 20(9), 747–757 https://doi org/10 1093/ijnp/pyx047
Poling, A D , & Appel, J B (1982) Dependence-Producing Liability of LSD and Similar Psychotomimetics In F Hoffmeister & G Stille (Eds ), Psychotropic Agents: Vol 55 / 3 (pp 111–116) Springer Berlin Heidelberg https://doi org/10 1007/978-3-642-67770-0 6
Polito, V, & Liknaitzky, P (2022) The emerging science of microdosing: A systematic review of research on low dose psychedelics (1955–2021) and recommendations for the field Neuroscience & Biobehavioral Reviews, 139, 104706 https://doi.org/10.1016/j.neubiorev.2022.104706
Polito, V, & Liknaitzky, P (2024) Is microdosing a placebo? A rapid review of low-dose LSD and psilocybin research. Journal of Psychopharmacology, 38(8), 701–711. https://doi.org/10.1177/02698811241254831
Polito, V, & Stevenson, R J (2019) A systematic study of microdosing psychedelics PLOS ONE, 14(2), e0211023. https://doi.org/10.1371/journal.pone.0211023
Ponté, C , & Lapeyre-Mestre, M (2017) [Psychoactive effects of “legal high”: About lysergic acid amide (LSA)]. Therapie, 72(5), 605–608. https://doi.org/10.1016/j.therap.2017.01.012
Ponterotto, J G (n d ) Full results and participant quotes from “A qualitative inquiry into ethical relationship and boundary-setting in underground psychedelic healing.”
Pontual, A A D D , Tófoli, L F, Collares, C F, Ramaekers, J G , & Corradi-Webster, C M (2021). The Setting Questionnaire for the Ayahuasca Experience: Questionnaire Development and Internal Structure. Frontiers in Psychology, 12, 679016. https://doi org/10 3389/fpsyg 2021 679016
Pontual, A. A. de D., Tófoli, L. F., Corradi-Webster, C. M., van Oorsouw, K., Delgado, A. R. O., & Ramaekers, J. G. (2022). The influence of ceremonial settings on mystical and challenging experiences occasioned by ayahuasca: A survey among ritualistic and religious ayahuasca users Frontiers in Psychology, 13, 857372 https://doi org/10 3389/fpsyg 2022 857372
Poppe, C , & Repantis, D (n d ) Ethical Aspects of Psychedelic-Assisted Treatments: An Overview (pp 1–16) Springer https://doi org/10 1007/7854 2024 533
Poyatos, L , Pérez-Mañá, C , Hladun, O , Núñez-Montero, M , de la Rosa, G , Martín, S , Barriocanal, A M , Carabias, L , Kelmendi, B , Taoussi, O , Busardò, F P, Fonseca, F, Torrens, M , Pichini, S , Farré, M , & Papaseit, E (2023) Pharmacological effects of methylone and MDMA in humans Frontiers in Pharmacology, 14, 1122861 https://doi.org/10.3389/fphar.2023.1122861
Prevalence and epidemiological associates of novel psychedelic use in the United States adult population James D Sexton, Michael S Crawford, Noah W Sweat, Allyson Varley, Emma E Green, Peter S Hendricks, 2019. (n.d.). Retrieved January 12, 2025, from https://journals.sagepub.com/doi/10.1177/0269881119827796
Price, C. M., Feduccia, A. A., & DeBonis, K. (2022). Effects of Selective Serotonin Reuptake
Inhibitor Use on 3,4-Methylenedioxymethamphetamine-Assisted Therapy for Posttraumatic Stress Disorder: A Review of the Evidence, Neurobiological Plausibility, and Clinical Significance Journal of Clinical Psychopharmacology, 42(5), 464–469
https://doi org/10 1097/JCP0000000000001595
Pronovost-Morgan, C , Hartogsohn, I , & Ramaekers, J G (2023) Harnessing placebo: Lessons from psychedelic science Journal of Psychopharmacology, 37(9), 866–875
https://doi org/10 1177/02698811231182602
Psychedelic Drug Crises: Toxicity and Therapeutics | Request PDF (2024) ResearchGate https://wwwresearchgate net/publication/233116091 Psychedelic Drug Crises Toxicity and T herapeutics
Psychedelic medicalization, public discourse, and the morality of ego dissolution (n d ) Blossom. Retrieved January 4, 2025, from https://blossomanalysis.com/papers/psychedelic-medicalization-public-discourse-and-the-morali ty-of-ego-dissolution/
Psychedelic medicalization, public discourse, and the morality of ego dissolution | Request PDF (n.d.). Retrieved January 4, 2025, from https://www.researchgate.net/publication/352319926 Psychedelic medicalization public disco urse and the morality of ego dissolution
Psychedelic medicalization, public discourse, and the morality of ego dissolution Alex K Gearin, Neşe Devenot, 2021 (n d ) Retrieved January 4, 2025, from https://journals sagepub com/doi/abs/10 1177/13678779211019424?journalCode=icsa
Rabinowitz, J., Lev-Ran, S., & Gross, R. (2023). The association between naturalistic use of psychedelics and co-occurring substance use disorders Frontiers in Psychiatry, 13, 1066369 https://doi org/10 3389/fpsyt 2022 1066369
Racial Disparities in Access to Psychedelic Treatments and Inclusion in Research Trials | Psychiatric Annals (n d ) Retrieved February 27, 2025, from https://journals healio com/doi/10 3928/00485713-20221123-01
Rahayu, Y, Riyanto, A , & Wibowo, A (2019) Relationship Of Magic Mushroom Literation As A Drug With Abuse It’s Use As A Hallucination International Journal on Advanced Science, Education, and Religion, 2(1), 27–34 https://doi org/10 33648/ijoaserv2i1 25
Raison, C L , Jain, R , Penn, A D , Cole, S P, & Jain, S (2022) Effects of Naturalistic Psychedelic Use on Depression, Anxiety, and Well-Being: Associations With Patterns of Use, Reported Harms, and Transformative Mental States. Frontiers in Psychiatry, 13, 831092. https://doi.org/10.3389/fpsyt.2022.831092
Raison, C. L., Sanacora, G., Woolley, J., Heinzerling, K., Dunlop, B. W., Brown, R. T., Kakar, R., Hassman, M., Trivedi, R. P., Robison, R., Gukasyan, N., Nayak, S. M., Hu, X., O’Donnell, K. C., Kelmendi, B., Sloshower, J., Penn, A. D., Bradley, E., Kelly, D. F., … Griffiths, R. R. (2023). Single-Dose Psilocybin Treatment for Major Depressive Disorder: A Randomized Clinical Trial JAMA, 330(9), 843–853 https://doi org/10 1001/jama 2023 14530
Raj, G (2022) Psychedelic use in India, its pattern and personal significance – findings from an online survey Indian Journal of Psychiatry, 64(4), 428–429 https://doi org/10 4103/indianjpsychiatryindianjpsychiatry 447 21
Raja, S M , Guptill, J T, Mack, M , Peterson, M , Byard, S , Twieg, R , Jordan, L , Rich, N , Castledine, R , Bourne, S , Wilmshurst, M , Oxendine, S , Avula, S G C , Zuleta, H , Quigley, P, Lawson, S , McQuaker, S J , Ahmadkhaniha, R , Appelbaum, L G , Thomas, C J (2024). A Phase 1 Assessment of the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of (2R,6R)-Hydroxynorketamine in Healthy Volunteers. Clinical Pharmacology and Therapeutics, 116(5), 1314–1324 https://doi org/10 1002/cpt 3391
Rajwani, K. (2022). Should Adolescents be Included in Emerging Psychedelic Research? Canadian Journal of Bioethics, 5(2), 36. https://doi.org/10.7202/1089784ar
Ramaekers, J G , & Kuypers, K P C (2006) Acute Effects of 3,4-Methylenedioxymethamphetamine (MDMA) on Behavioral Measures of Impulsivity: Alone and in Combination with Alcohol. Neuropsychopharmacology, 31(5), 1048–1055. https://doi org/10 1038/sj npp 1300894
Ramaekers, J. G., Reckweg, J. T., & Mason, N. L. (2025). Benefits and Challenges of Ultra-Fast, Short-Acting Psychedelics in the Treatment of Depression American Journal of Psychiatry, 182(1), 33–46 https://doi org/10 1176/appi ajp 20230890
Ramaekers, J. G., Reckweg, J. T., Mason, N. L., Kuypers, K. P. C., Toennes, S. W., & Theunissen, E L (2024) Safety and cognitive pharmacodynamics following dose escalations with 3-methylmethcathinone (3-MMC): A first in human, designer drug study Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology. https://doi.org/10.1038/s41386-024-02042-7
Reichelt, A (2022) Complexities of psychedelics for therapeutic use in obesity and eating disorders Journal of Psychiatry and Neuroscience, 47(5), E366–E366 https://doi.org/10.1503/jpn.220135-l
Rekatsina, M , Moka, E , Vadalouca, A , & Varrassi, G (2022) SP56 Psychedelic drugs and pain. Invited Speakers, A64–A64. https://doi.org/10.1136/rapm-2022-ESRA.62
Riba, J , & Barbanoj, M J (2005) Bringing ayahuasca to the clinical research laboratory Journal of Psychoactive Drugs, 37(2), 219–230. https://doi.org/10.1080/02791072.2005.10399804
Rickli, A., Luethi, D., Reinisch, J., Buchy, D., Hoener, M. C., & Liechti, M. E. (2015). Receptor interaction profiles of novel N-2-methoxybenzyl (NBOMe) derivatives of 2,5-dimethoxy-substituted phenethylamines (2C drugs). Neuropharmacology, 99, 546–553. https://doi org/10 1016/j neuropharm 2015 08 034
Riva-Posse, P., Reiff, C. M., Edwards, J. A., Job, G. P., Galendez, G. C., Garlow, S. J., Saah, T. C , Dunlop, B W, & McDonald, W M (2018) Blood pressure safety of subanesthetic ketamine for depression: A report on 684 infusions Journal of Affective Disorders, 236, 291–297
https://doi org/10 1016/j jad 2018 02 025
Rms*, C (2024) Psychedelic Mushrooms: The Use of Psilocybin in the Treatment of Mental Disorders Annals of Bioethics & Clinical Applications, 7(1) https://doi org/10 23880/abca-16000266
Roberts, C A , Osborne-Miller, I , Cole, J , Gage, S H , & Christiansen, P (2020) Perceived harm, motivations for use and subjective experiences of recreational psychedelic “magic” mushroom use. Journal of Psychopharmacology (Oxford, England), 34(9), 999–1007. https://doi.org/10.1177/0269881120936508
Robinson, C , Slitzky, M , Schatman, M , Yong, R , Lehman, A , Kaynar, A M , Shivanekar, S , & Emerick, T. (2024). Ethical Considerations Regarding Psychedelics for Clinical Pain Research. Journal of Pain Research, Volume 17, 4357–4364. https://doi.org/10.2147/JPR.S491470
Robinson, O. C., Evans, J., Luke, D., McAlpine, R., Sahely, A., Fisher, A., Sundeman, S., Ketzitzidou Argyri, E., Murphy-Beiner, A., Michelle, K., & Prideaux, E. (2024). Coming back together: A qualitative survey study of coping and support strategies used by people to cope with extended difficulties after the use of psychedelic drugs Frontiers in Psychology, 15, 1369715 https://doi org/10 3389/fpsyg 2024 1369715
Robinson, O C , Evans, J , McAlpine, R G , Argyri, E K , & Luke, D (2024) An investigation into the varieties of extended difficulties following psychedelic drug use: Duration, severity and helpful coping strategies https://doi org/10 1556/2054 2024 00420
Robinson, O , Evans, J , Luke, D , McAlpine, R , Sahely, A , Fisher, A , Sundeman, S , Argyri, E K , Murphy-Beiner, A , Michelle, K , & Prideaux, E (2024) Coming Back Together: A Qualitative Survey Study of Coping and Support Strategies Used by People to Cope With Extended Difficulties After the Use of Psychedelic Drugs (SSRN Scholarly Paper No. 4687209). Social Science Research Network. https://doi.org/10.2139/ssrn.4687209
Rocha, J. M., Reis, J. A. S., Bouso, J. C., Hallak, J. E. C., & Dos Santos, R. G. (2023). Identifying setting factors associated with improved ibogaine safety: A systematic review of clinical studies European Archives of Psychiatry and Clinical Neuroscience, 273(7), 1527–1542 https://doi org/10 1007/s00406-023-01590-1
Rodolico, A., Cutrufelli, P., Di Francesco, A., Aguglia, A., Catania, G., Concerto, C., Cuomo, A., Fagiolini, A , Lanza, G , Mineo, L , Natale, A , Rapisarda, L , Petralia, A , Signorelli, M S , & Aguglia, E (2024) Efficacy and safety of ketamine and esketamine for unipolar and bipolar depression: An overview of systematic reviews with meta-analysis Frontiers in Psychiatry, 15, 1325399. https://doi.org/10.3389/fpsyt.2024.1325399
Rodrigues, L S , Reis, J A S , Rossi, G N , Guerra, L T L , Maekawa, R M , de Lima Osório, F, Bouso, J C , Santos, F P, Paranhos, B A P B , Yonamine, M , Hallak, J E C , & dos Santos, R. G. (2024). Effects of a Single Dose of Ayahuasca in College Students With Harmful Alcohol Use: A Single-blind, Feasibility, Proof-of-Concept Trial. Journal of Clinical Psychopharmacology, 44(4), 402 https://doi org/10 1097/JCP0000000000001872
Rodríguez Arenas, M. A., Barrio Anta, G., de la Fuente de Hoz, L., & Royuela, L. (1997). [Emergencies associated with the consumption of designer drugs, hallucinogens and amphetamines treated at 15 Spanish hospitals in 1994 Work Group on the Study of Emergencies due to Psychostimulants] Revista Clinica Espanola, 197(12), 804–809
Rolando, S , & Beccaria, F (2019) “The junkie abuses, the psychonaut learns”: A qualitative analysis of an online drug forum community Drugs and Alcohol Today, 19(4), 282–294 https://doi org/10 1108/DAT-10-2018-0052
Romeo, B , Kervadec, E , Fauvel, B , Strika-Bruneau, L , Amirouche, A , Verroust, V, Piolino, P, & Benyamina, A. (2024). Safety and risk assessment of psychedelic psychotherapy: A meta-analysis and systematic review. Psychiatry Research, 335, 115880. https://doi org/10 1016/j psychres 2024 115880
Rosa, W. E., Sager, Z., Miller, M., Bernstein, I., Doerner Rinaldi, A., Addicott, K., Ljuslin, M., Adrian, C , Back, A L , Beachy, J , Bossis, A P, Breitbart, W S , Cosimano, M P, Fischer, S M , Guss, J , Knighton, E , Phelps, J , Richards, B D , Richards, W A , Beaussant, Y (2022) Top Ten Tips Palliative Care Clinicians Should Know About Psychedelic-Assisted Therapy in the Context of Serious Illness Journal of Palliative Medicine, 25(8), 1273–1281 https://doi.org/10.1089/jpm.2022.0036
Rose, J R (2024) Memory, trauma, and self: Remembering and recovering from sexual abuse in psychedelic-assisted therapy. Journal of Psychedelic Studies. https://doi.org/10.1556/2054.2024.00363
Roseman, L , Nutt, D J , & Carhart-Harris, R L (2018) Quality of acute psychedelic experience predicts therapeutic efficacy of psilocybin for treatment-resistant depression. Frontiers in Pharmacology, 8. https://doi.org/10.3389/fphar.2017.00974
Roseman, L., Erritzoe, D., Nutt, D., Carhart-Harris, R., & Timmermann, C. (2024). Interrupting the Psychedelic Experience Through Contextual Manipulation to Study Experience Efficacy. JAMA Network Open, 7(7), e2422181 https://doi org/10 1001/jamanetworkopen 2024 22181
Rosenbaum, D., Cho, M., Schneider, E., Hales, S., & Buchman, D. Z. (2023). Ethical Considerations at the Intersection Between Psychedelic-Assisted Psychotherapy and Medical Assistance in Dying AJOB Neuroscience, 14(2), 139–141 https://doi org/10 1080/21507740 2023 2188297
Rosenbaum, D , Hare, C , Hapke, E , Herman, Y, Abbey, S E , Sisti, D , & Buchman, D Z (2024) Experiential Training in Psychedelic-Assisted Therapy: A Risk-Benefit Analysis Hastings Center Report, 54(4), 32–46 https://doi org/10 1002/hast 1602
Rosenbaum, D , Weissman, C , Anderson, T, Petranker, R , Dinh-Williams, L -A , Hui, K , & Hapke, E (2020) Microdosing psychedelics: Demographics, practices, and psychiatric comorbidities Journal of Psychopharmacology, 34(6), 612–622 https://doi.org/10.1177/0269881120908004
Rosenblat, J D , Husain, M I , Lee, Y, McIntyre, R S , Mansur, R B , Castle, D , Offman, H , Parikh, S. V., Frey, B. N., Schaffer, A., Greenway, K. T., Garel, N., Beaulieu, S., Kennedy, S. H., Lam, R. W., Milev, R., Ravindran, A. V., Tourjman, V., Ameringen, M. V., … Taylor, V. (2023). The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: Serotonergic Psychedelic Treatments for Major Depressive Disorder The Canadian Journal of Psychiatry, 68(1), 5–21 https://doi org/10 1177/07067437221111371
Ross, S , Bossis, A , Guss, J , Agin-Liebes, G , Malone, T, Cohen, B , Mennenga, S E , Belser, A., Kalliontzi, K., Babb, J., Su, Z., Corby, P., & Schmidt, B. L. (2016). Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial Journal of Psychopharmacology, 30(12), 1165–1180 https://doi org/10 1177/0269881116675512
Rossi, G N , Hallak, J E C , Bouso Saiz, J C , & Dos Santos, R G (2022) Safety issues of psilocybin and LSD as potential rapid acting antidepressants and potential challenges Expert Opinion on Drug Safety, 21(6), 761–776 https://doi org/10 1080/14740338 2022 2066650
Rossi, G N , Rocha, J M , Osório, F L , Bouso, J C , Ona, G , Silveira, G de O , Yonamine, M , Bertozi, G , Crevelin, E J , Queiroz, M E , Crippa, J A S , Hallak, J E C , & Dos Santos, R G (2023) Interactive Effects of Ayahuasca and Cannabidiol in Social Cognition in Healthy Volunteers: A Pilot, Proof-of-Concept, Feasibility, Randomized-Controlled Trial. Journal of Clinical Psychopharmacology, 43(4), 339–349. https://doi.org/10.1097/JCP.0000000000001691
Rouaud, A , Calder, A E , & Hasler, G (2024) Microdosing psychedelics and the risk of cardiac fibrosis and valvulopathy: Comparison to known cardiotoxins. Journal of Psychopharmacology, 38(3), 217–224. https://doi.org/10.1177/02698811231225609
Ruane, D. (2015). Harm Reduction or Psychedelic Support? Caring for Drug-Related Crises at Transformational Festivals. Dancecult, 7(1), 55–75. https://doi org/10 12801/1947-5403 2015 07 01 03
Rucker, J. J., Roberts, C., Seynaeve, M., Young, A. H., Suttle, B., Yamamoto, T., Ermakova, A. O., Dunbar, F., & Wiegand, F. (2024). Phase 1, placebo-controlled, single ascending dose trial to evaluate the safety, pharmacokinetics and effect on altered states of consciousness of intranasal BPL-003 (5-methoxy- N,N -dimethyltryptamine benzoate) in healthy participants Journal of Psychopharmacology, 38(8), 712–723 https://doi org/10 1177/02698811241246857
Rucker, J , Seynaeve, M , Young, A H , Roberts, C , Suttle, B , Yamamoto, T, Ermakova, A O , Dunbar, F, & Wiegand, F (2023) 105 Intranasal 5-MeO-DMT: Safety, PK and Effect on Altered States of Consciousness in Healthy Volunteers Biological Psychiatry, 93(9, Supplement), S136 https://doi.org/10.1016/j.biopsych.2023.02.345
Russ, S L , Carhart-Harris, R L , Maruyama, G , & Elliott, M S (2019) States and traits related to the quality and consequences of psychedelic experiences. Psychology of Consciousness: Theory, Research, and Practice, 6(1), 1–21. https://doi.org/10.1037/cns0000169
Ryan, E., & Kulkarni, J. (2023). A potential role for onabotulinumtoxinA in the management of Hallucinogen persisting perception disorder. Australasian Psychiatry: Bulletin of Royal Australian and New Zealand College of Psychiatrists, 31(2), 230–231 https://doi org/10 1177/10398562231154107
Ryan, R S , Copello, A , & Fox, A P (2023) Experiences of microdosing psychedelics in an attempt to support wellbeing and mental health. BMC Psychiatry, 23(1), 160. https://doi.org/10.1186/s12888-023-04628-9
Sabé, M., Sulstarova, A., Glangetas, A., De Pieri, M., Mallet, L., Curtis, L., Richard-Lepouriel, H., Penzenstadler, L., Seragnoli, F., Thorens, G., Zullino, D., Preller, K., Böge, K., Leucht, S., Correll, C U , Solmi, M , Kaiser, S , & Kirschner, M (2024) Reconsidering evidence for psychedelic-induced psychosis: An overview of reviews, a systematic review, and meta-analysis of human studies Molecular Psychiatry, 1–33 https://doi org/10 1038/s41380-024-02800-5
Safety pharmacology of acute mescaline administration in healthy participants · ivySCI (n d ) ivySCI Retrieved January 14, 2025, from https://wwwivysci com/articles/7059896 Safety pharmacology of acute mescaline administr ation in healthy participants
Safety, Tolerability, and Efficacy of Psilocybin in 9 Patients With Obsessive-Compulsive Disorder (n d ) Psychiatrist Com Retrieved January 4, 2025, from https://www.psychiatrist.com/jcp/safety-tolerability-efficacy-psilocybin-patients-obsessive/
Sakai, K , Bradley, E R , Zamaria, J A , Agin-Liebes, G , Kelley, D P, Fish, A , Martini, V, Ferris, M. C., Morton, E., Michalak, E. E., O’Donovan, A., & Woolley, J. D. (2024). Content analysis of Reddit posts about coadministration of selective serotonin reuptake inhibitors and psilocybin mushrooms Psychopharmacology, 241(8), 1617–1630
https://doi org/10 1007/s00213-024-06585-x
Salzman, C., & Abraham, H. D. (2017). Hallucinogen Persisting Perception Disorder Following Therapeutic Ketamine: A Case Report Journal of Alcoholism & Drug Dependence, 05(05)
https://doi org/10 4172/2329-6488 1000281
Sami, M , Piggott, K , Coysh, C , & Fialho, A (2015) Psychosis, psychedelic substance misuse and head injury: A case report and 23 year follow-up Brain Injury, 29(11), 1383–1386
https://doi org/10 3109/02699052 2015 1046491
Sanchez Petrement, M (2023) Psychedelic therapy as reality transformation: A phenomenological approach Journal of Psychedelic Studies, 7(1), 36–47
https://doi org/10 1556/2054 2023 00231
Sanders, B , Lankenau, S E , Bloom, J J , & Hathazi, D (2008) “Research Chemicals”: Tryptamine and Phenethylamine Use Among High-Risk Youth Substance Use & Misuse, 43(3–4), 389–402. https://doi.org/10.1080/00952990701202970
Sapkota, A , Khurshid, H , Qureshi, I A , Jahan, N , Went, T R , Sultan, W, & Alfonso, M (2021). Efficacy and Safety of Intranasal Esketamine in Treatment-Resistant Depression in Adults: A Systematic Review. Cureus. https://doi.org/10.7759/cureus.17352
Sarparast, A , Thomas, K , Malcolm, B , & Stauffer, C S (2022) Drug-drug interactions between psychiatric medications and MDMA or psilocybin: A systematic review. Psychopharmacology, 239(6), 1945–1976. https://doi.org/10.1007/s00213-022-06083-y
Savides, I. A., & Outhoff, K. (2024). Less is more? A review of psilocybin microdosing. Journal of Psychopharmacology, 38(10), 846–860. https://doi.org/10.1177/02698811241278769
Scala, M., Fabbri, C., Fusar-Poli, P., Di Lorenzo, G., Ferrara, M., Amerio, A., Fusar-Poli, L., Pichiecchio, A., Asteggiano, C., Menchetti, M., De Ronchi, D., MNESYS - Mood and Psychosis
Sub-Project (Spoke 5), Fanelli, G., & Serretti, A. (2024). The revival of psilocybin between scientific excitement, evidence of efficacy, and real-world challenges CNS Spectrums, 1–15
https://doi org/10 1017/S1092852924002268
Scarlatti, F (2023) The Relationship between Plasticity in the Primary Visual Cortex and the Hallucinatory Persisting Perception Disorder PsyArXiv https://doi org/10 31234/osf io/gfuet
Schatten, H , Eter, N , & Mihailovic, N (2020) „Visual snow“ bei „Hallucinogen Persisting Perception Disorder“ Der Ophthalmologe, 117(11), 1112–1115 https://doi org/10 1007/s00347-020-01056-y
Schlag, A K , Aday, J , Salam, I , Neill, J C , & Nutt, D J (2022) Adverse effects of psychedelics: From anecdotes and misinformation to systematic science Journal of Psychopharmacology, 36(3), 258–272 https://doi org/10 1177/02698811211069100
Schleim, S (2022) Grounded in Biology: Why the Context-Dependency of Psychedelic Drug Effects Means Opportunities, Not Problems for Anthropology and Pharmacology Frontiers in Psychiatry, 13, 906487. https://doi.org/10.3389/fpsyt.2022.906487
Scopus preview Scopus Document details Anticholinergic toxicity after the ingestion of serotonergic “magic mushrooms ” (n d ) Retrieved January 4, 2025, from https://www.scopus.com/record/display.uri?eid=2-s2.0-84866140419&origin=inward&txGid=a33 5cb6bccc0e713f05d897c6079b26a
Section 1 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ. (n.d.). Retrieved January 27, 2025, from https://www.samhsa.gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect1pe htm
Section 3 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ (n d ) Retrieved January 27, 2025, from https://wwwsamhsa gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect3pe htm
Section 4 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ (n d -a) Retrieved January 27, 2025, from
https://wwwsamhsa gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect4pe.htm
Section 4 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ. (n.d.-b). Retrieved January 27, 2025, from https://www.samhsa.gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect4pe htm
Section 5 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ. (n.d.). Retrieved January 27, 2025, from https://wwwsamhsa gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect5pe htm
Section 7 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ (n d ) Retrieved January 27, 2025, from https://wwwsamhsa gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect7pe htm
Section 8 PE Tables Results from the 2023 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ (n d ) Retrieved January 27, 2025, from https://www.samhsa.gov/data/sites/default/files/reports/rpt47100/NSDUHDetailedTabs2023/NSD UHDetailedTabs2023/2023-nsduh-detailed-tables-sect8pe.htm
Sessa, B., & Nutt, D. (2015). Making a medicine out of MDMA. The British Journal of Psychiatry: The Journal of Mental Science, 206(1), 4–6. https://doi.org/10.1192/bjp.bp.114.152751
Sevigny, E. L., Thyssen, S., Erowid, E., & Lea, R. (2024). Misrepresentation of MDMA in the United States, 1999–2023. Drug and Alcohol Dependence, 264, 112467. https://doi.org/10.1016/j.drugalcdep.2024.112467
Sexton, J. D., Crawford, M. S., Sweat, N. W., Varley, A., Green, E. E., & Hendricks, P. S. (2019). Prevalence and epidemiological associates of novel psychedelic use in the United States adult population Journal of Psychopharmacology https://doi org/10 1177/0269881119827796
Shane, D., Cho, M., & Akhtar, S. (2024). Psychedelics in medicine A call for educational action. Canadian Medical Education Journal, 15(4), 132–133. https://doi org/10 36834/cmej 78844
Sharp, J. L., & Smith, M. A. (2021). The Effects of Drugs on Behavior Maintained by Social Contact: Role of Monoamines in Social Reinforcement Frontiers in Behavioral Neuroscience, 15, 805139 https://doi org/10 3389/fnbeh 2021 805139
Shaw, L , Rea, K , Lachowsky, N J , & Roth, E A (2023) Magic Mushroom Use: A Qualitative Interview Study of Post-Trip Impacts and Strategies for Optimizing Experiences Journal of Psychoactive Drugs, 55(2), 151–158 https://doi org/10 1080/02791072 2022 2054746
Short, B , Fong, J , Galvez, V, Shelker, W, & Loo, C K (2018) Side-effects associated with ketamine use in depression: A systematic review. The Lancet. Psychiatry, 5(1), 65–78. https://doi.org/10.1016/S2215-0366(17)30272-9
Sicignano, D., Snow-Caroti, K., Hernandez, A. V., & White, C. M. (2023). The Impact of Psychedelic Drugs on Anxiety and Depression in Advanced Cancer or other Life-threatening Disease: A Systematic Review With Meta-analysis American Journal of Clinical Oncology, 46(6), 236–245 https://doi org/10 1097/COC 0000000000000998
Side Effects and Safety Issues of Psychedelic Drugs | Request PDF. (2024). ResearchGate. https://doi org/10 37122/kaap 2023 27 2 49
Simmler, L. D., Li, Y., Hadjas, L. C., Hiver, A., van Zessen, R., & Lüscher, C. (2022). Dual action of ketamine confines addiction liability Nature, 608(7922), 368–373 https://doi org/10 1038/s41586-022-04993-7
Simon, M W, Olsen, H A , Hoyte, C O , Black, J C , Reynolds, K M , Dart, R C , & Monte, A A (2024) Clinical Effects of Psychedelic Substances Reported to United States Poison Centers: 2012 to 2022 Annals of Emergency Medicine, 84(6), 605–618 https://doi org/10 1016/j annemergmed 2024 06 025
Simon Melanie, H L (2013) Hallucinogen Persisting Perception Disorder (HPPD) and Flashback-are they Identical? Journal of Alcoholism & Drug Dependence, 01(04) https://doi.org/10.4172/2329-6488.1000121
Simonsson, O , Goldberg, S B , Chambers, R , Osika, W, Simonsson, C , & Hendricks, P S (2023a). Psychedelic use and psychiatric risks. Psychopharmacology. https://doi.org/10.1007/s00213-023-06478-5
Simonsson, O , Goldberg, S B , Chambers, R , Osika, W, Simonsson, C , & Hendricks, P S (2023b). Psychedelic use and psychiatric risks. Psychopharmacology. https://doi.org/10.1007/s00213-023-06478-5
Simonsson, O., Goldberg, S. B., & Hendricks, P. S. (2024). Into the wild frontier: Mapping the terrain of adverse events in psychedelic-assisted therapies. Journal of Psychopharmacology, 02698811241292944. https://doi.org/10.1177/02698811241292944
Simonsson, O., Hendricks, P. S., Chambers, R., Osika, W., & Goldberg, S. B. (2023).
Prevalence and associations of challenging, difficult or distressing experiences using classic psychedelics Journal of Affective Disorders, 326, 105–110
https://doi org/10 1016/j jad 2023 01 073
Simonsson, O , Mosing, M A , Osika, W, Ullén, F, Larsson, H , Lu, Y, & Wesseldijk, L W (2024) Adolescent Psychedelic Use and Psychotic or Manic Symptoms JAMA Psychiatry, 81(6), 579–585 https://doi org/10 1001/jamapsychiatry2024 0047
Singh, G , Laucis, N C , Anbalagan, E , Malhotra, K , & Gopalkrishna, G (n d ) A case study of LSD induced late psychosis in a 19-year-old woman.
Singh, J A (2021a) Epidemiology of hospitalizations with hallucinogen use disorder: A 17-year U.S. National study. Journal of Addictive Diseases, 39(4), 545–549.
https://doi.org/10.1080/10550887.2021.1907503
Singh, J. A. (2021b). Epidemiology of hospitalizations with hallucinogen use disorder: A 17-year U.S. National study. Journal of Addictive Diseases, 39(4), 545–549.
https://doi.org/10.1080/10550887.2021.1907503
Skommer, J., Gunesh, K., & Polasek, T. M. (2024). Personality vulnerabilities and adverse event reporting in phase 1 clinical studies. Trials, 25(1), 488. https://doi org/10 1186/s13063-024-08321-4
Skryabin, V. Y., Vinnikova, M., Nenastieva, A., & Alekseyuk, V. (2018). Hallucinogen persisting perception disorder: A literature review and three case reports Journal of Addictive Diseases, 37(3–4), 268–278 https://doi org/10 1080/10550887 2019 1673655
Smith, D. T., Faber, S. C., Buchanan, N. T., Foster, D., & Green, L. (2022). The Need for Psychedelic-Assisted Therapy in the Black Community and the Burdens of Its Provision Frontiers in Psychiatry, 12, 774736 https://doi org/10 3389/fpsyt 2021 774736
Smith, W R , & Sisti, D (2021) Ethics and ego dissolution: The case of psilocybin Journal of Medical Ethics, 47(12), 807–814 https://doi org/10 1136/medethics-2020-106070
Soares, C M , Leite, Â , & Pinto, M (2023) Self-Care Practices with Psychedelics – A Qualitative Study of Users’ Perspectives Journal of Psychoactive Drugs, 55(2), 159–169 https://doi org/10 1080/02791072 2022 2071134
Sobel, J , Espinas, O E , & Friedman, S A (1971) Carotid Artery Obstruction Following LSD Capsule Ingestion Archives of Internal Medicine, 127(2), 290–291 https://doi org/10 1001/archinte 1971 00310140118016
Søgaard Juul, T, Ebbesen Jensen, M , & Fink-Jensen, A (2023) The use of classic psychedelics among adults: A Danish online survey study Nordic Journal of Psychiatry, 77(4), 367–378. https://doi.org/10.1080/08039488.2022.2125069
Soofi, H , & Forlini, C (2023) Psychedelic Research for Dementia Risks Perpetuating Structural Failures and Inadequacies in Aged Care AJOB Neuroscience, 14(2), 131–134 https://doi.org/10.1080/21507740.2023.2188291
Spriggs, M J , Murphy-Beiner, A , Murphy, R , Bornemann, J , Thurgur, H , & Schlag, A K (2023). ARC: A framework for access, reciprocity and conduct in psychedelic therapies. Frontiers in Psychology, 14, 1119115. https://doi.org/10.3389/fpsyg.2023.1119115
Srirangam, S , & Mercer, J (2012) Ketamine bladder syndrome: An important differential diagnosis when assessing a patient with persistent lower urinary tract symptoms. BMJ Case Reports, 2012, bcr2012006447. https://doi.org/10.1136/bcr-2012-006447
St. Arnaud, K. O., & Sharpe, D. (2023). Contextual Parameters Associated with Positive and Negative Mental Health in Recreational Psychedelic Users. Journal of Psychoactive Drugs, 55(1), 30–39 https://doi org/10 1080/02791072 2022 2039815
Stanicic, F., Zah, V., Grbic, D., & Angelo, D. D. (2024). Cost-effectiveness of midomafetamine-assisted therapy (MDMA-AT) in chronic and treatment-resistant post-traumatic stress disorder of moderate or higher severity: A health-economic model PLOS ONE, 19(11), e0313569 https://doi org/10 1371/journal pone 0313569
Stephan, J -F, & Karam, S (2024) Psilocybin-Assisted Therapy for Brain Cancer Related Existential Distress: A Case-Report Journal of Palliative Medicine
https://doi org/10 1089/jpm 2024 0277
Strassman, R J (1984a) Adverse reactions to psychedelic drugs A review of the literature The Journal of Nervous and Mental Disease, 172(10), 577–595 https://doi org/10 1097/00005053-198410000-00001
Strassman, R J (1984b) ADVERSE REACTIONS TO PSYCHEDELIC DRUGS A REVIEW OF THE LITERATURE: The Journal of Nervous and Mental Disease, 172(10), 577–595
https://doi.org/10.1097/00005053-198410000-00001
Strassman, R J , & Qualls, C R (1994) Dose-response study of N,N-dimethyltryptamine in humans. I. Neuroendocrine, autonomic, and cardiovascular effects. Archives of General Psychiatry, 51(2), 85–97. https://doi.org/10.1001/archpsyc.1994.03950020009001
Strassman, R J , Qualls, C R , Uhlenhuth, E H , & Kellner, R (1994) Dose-response study of N,N-dimethyltryptamine in humans. II. Subjective effects and preliminary results of a new rating scale. Archives of General Psychiatry, 51(2), 98–108. https://doi org/10 1001/archpsyc 1994 03950020022002
Straumann, I., Holze, F., Becker, A. M., Ley, L., Halter, N., & Liechti, M. E. (2024). Safety pharmacology of acute psilocybin administration in healthy participants. Neuroscience Applied, 3, 104060 https://doi org/10 1016/j nsa 2024 104060
Strauss, D., Salle, S. de la, Sloshower, J., & Williams, M. T. (2022). Research abuses against people of colour and other vulnerable groups in early psychedelic research Journal of Medical Ethics, 48(10), 728–737 https://doi org/10 1136/medethics-2021-107262
Strickland, J C , Garcia-Romeu, A , & Johnson, M W (n d ) Set and Setting: A Randomized Study of Different Musical Genres in Supporting Psychedelic Therapy
Strumila, R , Nobile, B , Korsakova, L , Lengvenyte, A , Olie, E , Lopez-Castroman, J , & Courtet, P. (2021). Psilocybin, a naturally occurring indoleamine compound, could be useful to prevent suicidal behaviors. Pharmaceuticals, 14(12), 1213. https://doi.org/10.3390/ph14121213
Studerus, E. (n.d.). Tolerability, Assessment, and Prediction of Psilocybin-Induced Altered States of Consciousness.
Studerus, E., Gamma, A., Kometer, M., & Vollenweider, F. X. (2012). Prediction of psilocybin response in healthy volunteers. PloS One, 7(2), e30800. https://doi.org/10.1371/journal.pone.0030800
Studerus, E., Kometer, M., Hasler, F., & Vollenweider, F. X. (2011). Acute, subacute and long-term subjective effects of psilocybin in healthy humans: A pooled analysis of experimental studies Journal of Psychopharmacology, 25(11), 1434–1452
https://doi org/10 1177/0269881110382466
Subramanian, N , & Doran, M (2014) Improvement of hallucinogen persisting perception disorder (HPPD) with oral risperidone: Case report Irish Journal of Psychological Medicine, 31(1), 47–49 https://doi org/10 1017/ipm 2013 59
Sumnall, H , Measham, F, Brandt, S , & Cole, J (2011) Salvia divinorum use and phenomenology: Results from an online survey Journal of Psychopharmacology, 25(11), 1496–1507 https://doi org/10 1177/0269881110385596
Supprian, T, Frey, U , Supprian, R , Rösler, M , & Wanke, K (2001) [Psychoactive mushrooms An update] Fortschritte Der Neurologie-Psychiatrie, 69(12), 597–602 https://doi.org/10.1055/s-2001-19180
Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences Theresa M Carbonaro, Matthew P Bradstreet, Frederick S Barrett, Katherine A MacLean, Robert Jesse, Matthew W Johnson, Roland R Griffiths, 2016. (n.d.). Retrieved January 12, 2025, from https://journals sagepub com/doi/10 1177/0269881116662634
Sutherland, I., Ho, M.-F., & Croarkin, P. E. (2025). Psychedelic Treatments in Adolescent Psychopharmacology: Considering Safety, Ethics, and Scientific Rigor. Journal of Child and Adolescent Psychopharmacology https://doi org/10 1089/cap 2024 0082
Suzuki, J., Dekker, M. A., Valenti, E. S., Arbelo Cruz, F. A., Correa, A. M., Poklis, J. L., & Poklis, A (2015) Toxicities associated with NBOMe ingestion-a novel class of potent hallucinogens: A review of the literature Psychosomatics, 56(2), 129–139 https://doi org/10 1016/j psym 2014 11 002
Swanson, L R , Jungers, S , Varghese, R , Cullen, K R , Evans, M D , Nielson, J L , & Schallmo, M -P (2024) Enhanced visual contrast suppression during peak psilocybin effects:
Psychophysical results from a pilot randomized controlled trial Journal of Vision, 24(12), 5 https://doi.org/10.1167/jov.24.12.5
Swieczkowski, D , Kwaśny, A , Pruc, M , Gaca, Z , Szarpak, L , & Cubała, W J (2025) Efficacy and safety of psilocybin in the treatment of Major Depressive Disorder (MDD): A dose-response network meta-analysis of randomized placebo-controlled clinical trials. Psychiatry Research, 344, 116337 https://doi org/10 1016/j psychres 2024 116337
Syed, O. A., Petranker, R., Fewster, E. C., Sobolenko, V., Beidas, Z., Husain, M. I., Lake, S., & Lucas, P. (n.d.-a). Global Trends in Psychedelic Microdosing: Demographics, Substance Testing Behavior, and Patterns of Use Journal of Psychoactive Drugs, 0(0), 1–11 https://doi org/10 1080/02791072 2024 2424284
Syed, O A , Petranker, R , Fewster, E C , Sobolenko, V, Beidas, Z , Husain, M I , Lake, S , & Lucas, P (n d -b) Preferences, Perceptions, and Environmental Considerations of Natural and Synthetic Psychedelic Substances: Findings from the Global Psychedelic Survey Journal of Psychoactive Drugs, 0(0), 1–11 https://doi org/10 1080/02791072 2024 2446445
Szigeti, B , Kartner, L , Blemings, A , Rosas, F, Feilding, A , Nutt, D J , Carhart-Harris, R L , & Erritzoe, D (2021) Self-blinding citizen science to explore psychedelic microdosing eLife, 10, e62878. https://doi.org/10.7554/eLife.62878
Szigeti, B , Winstock, A R , Erritzoe, D , & Maier, L J (2018) Are ecstasy induced serotonergic alterations overestimated for the majority of users? Journal of Psychopharmacology (Oxford, England), 32(7), 741–748. https://doi.org/10.1177/0269881118767646
Tabaac, B. J., Shinozuka, K., Arenas, A., Beutler, B. D., Cherian, K., Evans, V. D., Fasano, C., & Muir, O. S. (n.d.). Psychedelic Therapy: A Primer for Primary Care...: American Journal of Therapeutics. Retrieved January 4, 2025, from https://journals lwwcom/americantherapeutics/fulltext/2024/04000/psychedelic therapy a pri mer for primary care 1 aspx
Tabaac, B J , Shinozuka, K , Arenas, A , Beutler, B D , Cherian, K , Evans, V D , Fasano, C , & Muir, O S (2024) Psychedelic Therapy: A Primer for Primary Care Clinicians Psilocybin
American Journal of Therapeutics, 31(2), e121–e132
https://doi org/10 1097/MJT0000000000001724
Tagen, M , Mantuani, D , van Heerden, L , Holstein, A , Klumpers, L E , & Knowles, R (2023) The risk of chronic psychedelic and MDMA microdosing for valvular heart disease Journal of Psychopharmacology (Oxford, England), 37(9), 876–890. https://doi.org/10.1177/02698811231190865
Taillefer de Laportalière, T., Jullien, A., Yrondi, A., Cestac, P., & Montastruc, F. (2023a).
Reporting of harms in clinical trials of esketamine in depression: A systematic review. Psychological Medicine, 53(10), 4305–4315. https://doi.org/10.1017/S0033291723001058
Taillefer de Laportalière, T, Jullien, A , Yrondi, A , Cestac, P, & Montastruc, F (2023b) Reporting of harms in clinical trials of esketamine in depression: A systematic review. Psychological Medicine, 53(10), 4305–4315. https://doi.org/10.1017/S0033291723001058
Targosz, D. (n.d.). Zatrucia grzybami halucynogennymi w Krakowie.
Tariq, R (2023) Using Psychedelics in Clinical Practice: Comparing Therapeutic Uses and Potential Harms. Current Reviews in Clinical and Experimental Pharmacology, 18(2), 94–109. https://doi.org/10.2174/2772432817666220321142707
Tate, S , Garel, N , Nash, K , & Lembke, A (2023) Trends in Hallucinogen-associated Emergency Department Visits and Hospitalizations in California from 2016–2021 (p. 2023.08.18.23294275). medRxiv. https://doi.org/10.1101/2023.08.18.23294275
Teixeira, P. J., Johnson, M., Timmermann, C., Watts, R., Erritzoe, D., Douglass, H., Kettner, H., & Carhart-Harris, R. (2021). Psychedelics and Health Behavior Change Journal of Psychopharmacology (in press) PsyArXiv https://doi org/10 31234/osf io/8vks6
Thal, S. B., Engel, L. B., & Bright, S. J. (2022). Sober sitter or coconsumer? Psychedelics, online forums and preferences for interpersonal interactions. Addiction Research & Theory, 30(5), 382–390 https://doi org/10 1080/16066359 2022 2065268
Thal, S. B., Wieberneit, M., Sharbanee, J. M., Skeffington, P. M., Baker, P., Bruno, R., Wenge, T, & Bright, S J (2022) Therapeutic (Sub)stance: Current practice and therapeutic conduct in preparatory sessions in substance-assisted psychotherapy-A systematized review Journal of Psychopharmacology (Oxford, England), 36(11), 1191–1207
https://doi.org/10.1177/02698811221127954
Thal, S , Engel, L B , & Bright, S J (2022) Presence, Trust, and Empathy: Preferred Characteristics of Psychedelic Carers Journal of Humanistic Psychology, 00221678221081380 https://doi.org/10.1177/00221678221081380
THE RENAISSANCE OF PSYCHEDELICS IN PSYCHIATRY: EVIDENCE, ETHICS, AND POTENTIAL IN MENTAL HEALTH TREATMENT FOR ADOLESCENTS | Request PDF. (2024). ResearchGate. https://doi.org/10.1016/j.jaac.2022.07.661
Timmermann, C., Watts, R., & Dupuis, D. (2022). Towards psychedelic apprenticeship: Developing a gentle touch for the mediation and validation of psychedelic-induced insights and revelations. Transcultural Psychiatry, 59(5), 691–704. https://doi org/10 1177/13634615221082796
Tupper, K. W. (2008a). Drugs, discourses and education: A critical discourse analysis of a high school drug education text Discourse: Studies in the Cultural Politics of Education, 29(2), 223–238 https://doi org/10 1080/01596300801966864
Tupper, K W (2008b) Teaching teachers to just say “know”: Reflections on drug education Teaching and Teacher Education, 24(2), 356–367. https://doi.org/10.1016/j.tate.2007.08.007
Tupper, K W (2014) Sex, drugs and the honour roll: The perennial challenges of addressing moral purity issues in schools. Critical Public Health, 24(2), 115–131. https://doi.org/10.1080/09581596.2013.862517
Turkia, M. (2022). Self-treatment of psychosis and complex post-traumatic stress disorder with LSD and DMT A retrospective case study. Psychiatry Research Case Reports, 1(2), 100029. https://doi.org/10.1016/j.psycr.2022.100029
Universidad de Chile, & Lolas Stepke, F. (2018). Para una ética de la estructuración farmacológica de las relaciones sociales. Persona, 1(021), 101–107. https://doi org/10 26439/persona2018 n021 1992
Urrutia, J., Anderson, B. T., Belouin, S. J., Berger, A., Griffiths, R. R., Grob, C. S., Henningfield, J E , Labate, B C , Maier, L J , Maternowska, M C , Weichold, F, Yaden, D B , & Magar, V (2023) Psychedelic Science, Contemplative Practices, and Indigenous and Other Traditional Knowledge Systems: Towards Integrative Community-Based Approaches in Global Health Journal of Psychoactive Drugs, 55(5), 523–538 https://doi.org/10.1080/02791072.2023.2258367
Uthaug, M V, Davis, A K , Haas, T F, Davis, D , Dolan, S B , Lancelotta, R , Timmermann, C , & Ramaekers, J. G. (2022a). The epidemiology of mescaline use: Pattern of use, motivations for consumption, and perceived consequences, benefits, and acute and enduring subjective effects. Journal of Psychopharmacology (Oxford, England), 36(3), 309–320. https://doi org/10 1177/02698811211013583
Uthaug, M. V., Davis, A. K., Haas, T. F., Davis, D., Dolan, S. B., Lancelotta, R., Timmermann, C., & Ramaekers, J G (2022b) The epidemiology of mescaline use: Pattern of use, motivations for consumption, and perceived consequences, benefits, and acute and enduring subjective effects
Journal of Psychopharmacology, 36(3), 309–320 https://doi org/10 1177/02698811211013583
Vamvakopoulou, I A , Narine, K A D , Campbell, I , Dyck, J R B , & Nutt, D J (2023)
Mescaline: The forgotten psychedelic Neuropharmacology, 222, 109294
https://doi org/10 1016/j neuropharm 2022 109294
van Amsterdam, J , Nutt, D , Phillips, L , & van den Brink, W (2015) European rating of drug harms Journal of Psychopharmacology (Oxford, England), 29(6), 655–660
https://doi.org/10.1177/0269881115581980
Van Beek, I (2009) HARM REDUCTION AN ETHICAL IMPERATIVE Addiction, 104(3), 342–343. https://doi.org/10.1111/j.1360-0443.2008.02418.x
van Dongen, R M , Alderliefste, G J , Onderwater, G L J , Ferrari, M D , & Terwindt, G M (2021) Migraine prevalence in visual snow with prior illicit drug use (hallucinogen persisting
perception disorder) versus without European Journal of Neurology, 28(8), 2631–2638
https://doi.org/10.1111/ene.14914
Van Dongen, R M , Alderliefste, G J , Onderwater, G L J , Ferrari, M D , & Terwindt, G M (2021). Migraine prevalence in visual snow with prior illicit drug use (hallucinogen persisting perception disorder) versus without. European Journal of Neurology, 28(8), 2631–2638. https://doi org/10 1111/ene 14914
Van Elk, M., & Fried, E. I. (2023). History repeating: A roadmap to address common problems in psychedelic science. PsyArXiv. https://doi.org/10.31234/osf.io/ak6gx
VanderZwaag, B., Garcia-Romeu, A., & Garcia-Barrera, M. A. (2024). Exploring psychedelic use in athletes and their attitudes toward psilocybin-assisted therapy in concussion recovery.
Therapeutic Advances in Psychopharmacology, 14, 20451253241264812
https://doi org/10 1177/20451253241264812
Vejmola, Č , Tylš, F, Piorecká, V, Koudelka, V, Kadeřábek, L , Novák, T, & Páleníček, T (2021) Psilocin, LSD, mescaline, and DOB all induce broadband desynchronization of EEG and disconnection in rats with robust translational validity Translational Psychiatry, 11(1), 506 https://doi org/10 1038/s41398-021-01603-4
Verne, Z , & Zabinski, J (2024) How Should We Expand Access to Psychedelics While Maintaining an Environment of Peace and Safety? AMA Journal of Ethics, 26(11), 868–874 https://doi.org/10.1001/amajethics.2024.868
Villalobos, C A , Bull, P, Sáez, P, Cassels, B K , & Huidobro-Toro, J P (2004a)
4-Bromo-2,5-dimethoxyphenethylamine (2C-B) and structurally related phenylethylamines are potent 5-HT2A receptor antagonists in Xenopus laevis oocytes. British Journal of Pharmacology, 141(7), 1167–1174. https://doi.org/10.1038/sj.bjp.0705722
Villalobos, C. A., Bull, P., Sáez, P., Cassels, B. K., & Huidobro-Toro, J. P. (2004b).
4-Bromo-2,5-dimethoxyphenethylamine (2C-B) and structurally related phenylethylamines are potent 5-HT2A receptor antagonists in Xenopus laevis oocytes British Journal of Pharmacology, 141(7), 1167–1174 https://doi org/10 1038/sj bjp 0705722
Villiger, D. (2024a). Giving Consent to the Ineffable. Neuroethics, 17(1), 11. https://doi org/10 1007/s12152-024-09545-6
Villiger, D. (2024b). How to Make Psychedelic-Assisted Therapy Safer. Cambridge Quarterly of Healthcare Ethics, 1–15 https://doi org/10 1017/S0963180124000604
Villiger, D., & Trachsel, M. (2023). With great power comes great vulnerability: An ethical analysis of psychedelics’ therapeutic mechanisms proposed by the REBUS hypothesis Journal of Medical Ethics, 49(12), 826–832 https://doi org/10 1136/jme-2022-108816
Viña, S M , & Stephens, A L (2023) Psychedelics and workplace harm Frontiers in Psychiatry, 14, 1186541. https://doi.org/10.3389/fpsyt.2023.1186541
Vogt, S B , Ley, L , Erne, L , Straumann, I , Becker, A M , Klaiber, A , & Liechti, M E (2023) Acute effects of intravenous DMT in a randomized placebo-controlled study in healthy participants. Translational Psychiatry, 13(1), 172. https://doi.org/10.1038/s41398-023-02477-4
Vollenweider, F. X., Gamma, A., Liechti, M., & Huber, T. (1998). Psychological and cardiovascular effects and short-term sequelae of MDMA (“ecstasy”) in MDMA-naïve healthy volunteers. Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 19(4), 241–251 https://doi org/10 1016/S0893-133X(98)00013-X
Vollenweider, F. X., & Preller, K. H. (2020). Psychedelic drugs: Neurobiology and potential for treatment of psychiatric disorders Nature Reviews Neuroscience, 21(11), 611–624 https://doi org/10 1038/s41583-020-0367-2
Vollenweider, F X , & Smallridge, J W (2022) Classic Psychedelic Drugs: Update on Biological Mechanisms Pharmacopsychiatry, 55(03), 121–138 https://doi org/10 1055/a-1721-2914
Vorobyeva, N., & Kozlova, A. A. (2022). Three Naturally-Occurring Psychedelics and Their Significance in the Treatment of Mental Health Disorders Frontiers in Pharmacology, 13, 927984 https://doi org/10 3389/fphar2022 927984
Wahba, M , Hayes, C , Kletter, M , & McAllister-Williams, R H (2024) Worsening suicidal ideation and prolonged adverse event following psilocybin administration in a clinical setting: Case report and thematic analysis of one participant’s experience BJPsych Open, 10(6), e229 https://doi.org/10.1192/bjo.2024.768
Walther, R F E , & van Schie, H T (2024) ‘Mind-Revealing’ Psychedelic States: Psychological Processes in Subjective Experiences That Drive Positive Change Psychoactives, 3(3), Article 3 https://doi.org/10.3390/psychoactives3030026
Waltzer, H (1972) Depersonalization and the use of LSD: A psychodynamic study American Journal of Psychoanalysis, 32(1), 45–52. https://doi.org/10.1007/BF01872483
Wang, E , Mathai, D S , Gukasyan, N , Nayak, S , & Garcia-Romeu, A (2024) Knowledge, attitudes, and concerns about psilocybin and MDMA as novel therapies among U.S. healthcare professionals. Scientific Reports, 14(1), 28022. https://doi.org/10.1038/s41598-024-78736-1
Weiss, B , Sleep, C E , Beller, N M , Erritzoe, D , & Campbell, W K (2023) Perceptions of psychedelic personality change, determinants of use, setting and drug moderation: Toward a holistic model. https://doi.org/10.1556/2054.2023.00291
Weiss, B., Wingert, A., Erritzoe, D., & Campbell, W. K. (2023). Prevalence and therapeutic impact of adverse life event reexperiencing under ceremonial ayahuasca. Scientific Reports, 13(1), 9438 https://doi org/10 1038/s41598-023-36184-3
Weleff, J , Anand, A , Dewey, E N , & Barnett, B S (2024) LSD use in the United States: Examining user demographics and their evolution from 2015–2019. https://doi.org/10.1556/2054.2024.00309
Wells, A., Fernandes, M., & Reynolds, L. (2024). Perceptions and attitudes towards psychedelic-assisted psychotherapy among health professionals, patients, and the public: A systematic review Journal of Psychedelic Studies, 8(1), 43–62 https://doi org/10 1556/2054 2023 00294
Wells, A., Muthukumaraswamy, A. P. S., Morunga, E., Evans, W., Cavadino, A., Bansal, M., Lawrence, N J , Ashley, A , Hoeh, N R , Sundram, F, Applebaum, A J , Parkinson, H , & Reynolds, L (2024) PAM trial protocol: A randomised feasibility study of psychedelic microdosing–assisted meaning-centred psychotherapy in advanced stage cancer patients Pilot and Feasibility Studies, 10(1), 29. https://doi.org/10.1186/s40814-024-01449-9
White, E , Kennedy, T, Ruffell, S , Perkins, D , & Sarris, J (2024) Ayahuasca and Dimethyltryptamine Adverse Events and Toxicity Analysis: A Systematic Thematic Review International Journal of Toxicology, 43(3), 327–339. https://doi.org/10.1177/10915818241230916
Wilkinson, S T, Palamar, J J , & Sanacora, G (2024) The Rapidly Shifting Ketamine Landscape in the US. JAMA Psychiatry, 81(3), 221–222. https://doi.org/10.1001/jamapsychiatry.2023.4945
Williams, M. L., Korevaar, D., Harvey, R., Fitzgerald, P. B., Liknaitzky, P., O’Carroll, S., Puspanathan, P., Ross, M., Strauss, N., & Bennett-Levy, J. (2021a). Translating Psychedelic Therapies From Clinical Trials to Community Clinics: Building Bridges and Addressing Potential Challenges Ahead Frontiers in Psychiatry, 12, 737738
https://doi org/10 3389/fpsyt 2021 737738
Williams, M L , Korevaar, D , Harvey, R , Fitzgerald, P B , Liknaitzky, P, O’Carroll, S , Puspanathan, P, Ross, M , Strauss, N , & Bennett-Levy, J (2021b) Translating Psychedelic Therapies From Clinical Trials to Community Clinics: Building Bridges and Addressing Potential Challenges Ahead Frontiers in Psychiatry, 12, 737738
https://doi.org/10.3389/fpsyt.2021.737738
Williams, M T, Davis, A K , Xin, Y, Sepeda, N D , Grigas, P C , Sinnott, S , & Haeny, A M (2021). People of color in North America report improvements in racial trauma and mental health symptoms following psychedelic experiences. Drugs: Education, Prevention and Policy, 28(3), 215–226 https://doi org/10 1080/09687637 2020 1854688
Williams, M. T., & Labate, B. C. (2019). Diversity, equity, and access in psychedelic medicine. Journal of Psychedelic Studies, 4(1), 1–3 https://doi org/10 1556/2054 2019 032
Wilson-Poe, A., Hoffman, K., Pertl, K., Luoma, J., Bazinet, A., Stauffer, C., McCarty, D., & Korthuis, P. (2024). Personal Psychedelic Experience as a Training Qualification for Facilitators:
A Thematic Analysis of Qualitative Interviews with Psilocybin Experts Journal of Psychoactive Drugs, 1–8. https://doi.org/10.1080/02791072.2024.2401982
Wolfgang, A S , Fonzo, G A , Gray, J C , Krystal, J H , Grzenda, A , Widge, A S , Kraguljac, N. V., McDonald, W. M., Rodriguez, C. I., & Nemeroff, C. B. (2025). MDMA and MDMA-Assisted Therapy. American Journal of Psychiatry, 182(1), 79–103. https://doi org/10 1176/appi ajp 20230681
Wolfgang, A. S., McClair, V. L., Schnurr, P. P., Holtzheimer, P. E., Woolley, J. D., Stauffer, C. S., Wolf, R. C., States, L. J., Benedek, D. M., Capaldi, V. F., Bradley, J., Fuller, M. A., Smyth, M. J., Hermes, E D A , Tenhula, W, & Wiechers, I R (2025) Research and Implementation of Psychedelic-Assisted Therapy in the Veterans Health Administration American Journal of Psychiatry, 182(1), 17–20 https://doi org/10 1176/appi ajp 20240751
Wolfson, E (2023) Psychedelic-supportive psychotherapy: A psychotherapeutic model for, before and beyond the medicine experience Journal of Psychedelic Studies, 6(3), 191–202 https://doi org/10 1556/2054 2022 00192
Wood, M J , McAlpine, R G , & Kamboj, S K (2024) Strategies for resolving challenging psychedelic experiences: Insights from a mixed-methods study Scientific Reports, 14(1), 28817 https://doi.org/10.1038/s41598-024-79931-w
Wright, K N , & Kabbaj, M (2018) Sex differences in sub-anesthetic ketamine’s antidepressant effects and abuse liability. Current Opinion in Behavioral Sciences, 23, 36–41. https://doi.org/10.1016/j.cobeha.2018.02.001
Yaden, D. B., Earp, B. D., & Griffiths, R. R. (2022). Ethical Issues Regarding Nonsubjective Psychedelics as Standard of Care. Cambridge Quarterly of Healthcare Ethics, 31(4), 464–471. https://doi.org/10.1017/S096318012200007X
Yang, J., Wang, N., Luo, W., & Gao, J. (2024). The efficacy and safety of MDMA-assisted psychotherapy for treatment of posttraumatic stress disorder: A systematic review and meta-analysis from randomized controlled trials Psychiatry Research, 339, 116043 https://doi org/10 1016/j psychres 2024 116043
Yildirim, B., Sahin, S. S., Gee, A., Jauhar, S., Rucker, J., Salgado-Pineda, P., Pomarol-Clotet, E , & McKenna, P (2024) Adverse psychiatric effects of psychedelic drugs: A systematic review of case reports Psychological Medicine, 54(15), 4035–4047 https://doi org/10 1017/S0033291724002496
Zeifman, R J , Singhal, N , Breslow, L , & Weissman, C R (2021) On the Relationship between Classic Psychedelics and Suicidality: A Systematic Review ACS Pharmacology & Translational Science, 4(2), 436–451. https://doi.org/10.1021/acsptsci.1c00024
Zeller, M (n d ) Psychedelic therapies and belief change: Are there risks of epistemic harm or epistemic injustice? Philosophical Psychology, 0(0), 1–32. https://doi.org/10.1080/09515089.2024.2362284
Zhou, K., De Wied, D., Carhart-Harris, R., & Kettner, H. (2022). Predictors Of Hallucinogen Persisting Perception Disorder Symptoms, Delusional Ideation And Magical Thinking Following Naturalistic Psychedelic Use PsyArXiv https://doi org/10 31234/osf io/txzha
Zhu, W., Ding, Z., Zhang, Y., Shi, J., Hashimoto, K., & Lu, L. (2016). Risks Associated with Misuse of Ketamine as a Rapid-Acting Antidepressant. Neuroscience Bulletin, 32(6), 557–564. https://doi org/10 1007/s12264-016-0081-2
Zimmermann, J., Zölch, N., Coray, R., Bavato, F., Friedli, N., Baumgartner, M. R., Steuer, A. E., Opitz, A , Werner, A , Oeltzschner, G , Seifritz, E , Stock, A -K , Beste, C , Cole, D M , & Quednow, B B (2023) Chronic 3,4-Methylenedioxymethamphetamine (MDMA) Use Is Related to Glutamate and GABA Concentrations in the Striatum But Not the Anterior Cingulate Cortex
The International Journal of Neuropsychopharmacology, 26(6), 438–450 https://doi.org/10.1093/ijnp/pyad023
