Autism Spectrum Disorder

BY STEPHEN A. WILSON

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. Neurodevelopmental disorders (ND) influence how the brain functions and alter nerve development, resulting in difficulties in social, cognitive, and emotional functioning. They start in childhood; sometimes diagnosis may not occur until adulthood. NDs include intellectual disabilities, learning disorders, sensory sensitivities, and social interactive challenges, among others. They can affect memory, language, behavior, learning, emotions, and motor skills. Most people with these diagnoses can effectively manage their challenges with the right interventions, support, and accommodations.

What is ASD? ASD and attention deficit hyperactivity disorder (ADHD) are the most common NDs. ASD affects how people see others and interact or socialize with them, which causes problems in communication and social interactions. In addition to persistent deficits in social communication and interaction across multiple contexts, people with ASD tend to have restricted, repetitive patterns of behavior, interests, or activities.

Symptoms have to be present from early childhood, cause clinically significant impairment, and not be explained better by intellectual disability or general developmental delay. It is a spectrum disorder because of the wide range and severity of symptoms. ASD includes conditions that were once thought to be separate — autism, Asperger’s syndrome, childhood disintegrative disorder, and other forms of developmental disorders not quite specified or named. There is also a spectrum of disability. Some people are cognitively intact and struggle more socially or emotionally; some are more globally affected. Most grow up to live healthy, productive, independent lives. Some can be more limited in their ability to function or live independently.

How is ASD diagnosed? The gold standard is a comprehensive, multidisciplinary evaluation using standardized tools such as the Autism Diagnostic Observation Schedule (ADOS-2) and the Autism Diagnostic Interview. There are no specific biomarkers or blood tests. Early signs include lack of response to name, limited gestures, and absence of imaginative play in the first two years of life. Screening is recommended for all children 18 to 24 months of age. If you notice these behaviors in a grandchild, family friend, nephew, or niece, recommend the child see their family doctor or pediatrician.

Who has ASD? ASD affects as many as 1 in 36 children in the United States, with a male-to-female ratio of about 4:1. It could be closer to 3:1, due to potential under diagnosis in females due to differences in symptom presentation and coping strategies. It has become more prevalent in the last few decades, likely due to changes in diagnostic criteria (how it is diagnosed), improved screening (we look regularly for it), and greater awareness (more people know about it and think of it as the cause for abnormal behaviors). Many of you probably recall someone who was a little different or odd growing up who would meet criteria for ASD today. People with ASD often have other health issues, including things like intellectual disability, epilepsy, anxiety, depression, and sleep disorders.

What causes ASD? There is no single cause. ASD is multifactorial, involving both genetic and environmental factors, with hundreds of genes and several chromosomal abnormalities implicated. Environmental risk factors include advanced parental age, maternal diabetes, prenatal infections, and exposure to certain medications or pollutants during pregnancy. For example, in some large observational studies, there was a slight association between acetaminophen during pregnancy and a small increased risk for ASD. Most of the studies did not show an association. Association is not causation. There are further studies examining if there may be a small subsection of people who may be genetically predisposed to the acetaminophen hypothesis. It is unfortunate that so many mothers with children with ASD will now be wondering if a few doses of acetaminophen “caused” it, that they “caused” it. Current data does not support this type of thinking.

Emerging research is exploring how environmental exposures may influence gene expression through something called epigenetic mechanisms, further highlighting the multifactorial nature of the etiology of this spectrum disorder.

How is ASD treated? No medications directly treat the core social communication deficits of ASD. The first approach is early, intensive behavioral intervention, particularly for children under 5 years, to improve language, play, and social communication. Some specific approaches can help improve core symptoms:

• Applied Behavior Analysis (ABA) is a widely used approach that reinforces positive behaviors and reduces problematic ones.

• Early Start Denver Model

• Speech and Language Therapy: Helps improve communication skills.

• Occupational Therapy: Focuses on daily living skills and sensory integration.

• Social Skills Training: Teaches appropriate social interactions and emotional regulation.

Medications are reserved for comorbid symptoms: irritability and aggression can be treated with risperidone and aripiprazole, for which both are FDA-approved; depression and anxiety can be treated with selective serotonin reuptake inhibitors (SSRI), and co-occurring ADHD can be treated with psychostimulants. Melatonin can be effective for sleep disturbances. Treatment should be individualized, target specific symptoms and comorbidities, and include family support and educational interventions.

ASD is a lifelong condition for which there is no cure. Early diagnosis and tailored interventions for symptom management, behavior modification, and skill development are key. With the right support, many individuals lead fulfilling and independent lives.

Dr. Stephen A. Wilson, MD, MPH, FAAFP, is Chair of Family Medicine at Boston University Chobanian and Avedisian School of Medicine and Chief of Family Medicine for Boston Medical Center.