The Increased Risk of Cardiovascular Complications due to Mental Illnesses

Aneesa Kumar

Introduction

Mental health disorders are characterised as clinically significant disturbances in the cognition, emotional regulation, or behaviour, of an individual and are usually associated with distress or impairment in key areas of functioning. These illnesses can range from the more common disorders, anxiety and depression, to others such as anorexia, post-traumatic stress disorder (PTSD) and schizophrenia.

For centuries, the mind-body relationship has been postulated and findings from various epidemiological studies have shown the impact of depression, trauma, anxiety, and stress on the physical body, including the cardiovascular system. As such, the damage to the system caused by mental distress can be regarded as a contributing risk factor to heart disease. According to the World Health Organisation (2022) in the world health statistics, some of the most common behavioural and metabolic risk factors, e.g. substance abuse and hypertension, for non-communicable diseases (NCDs) such as cardiovascular disease (CVD) are often linked to poor mental health, particularly mentally induced stress. A recent study led by senior research investigator in behavioural health, Rossom R. (2022), also found the estimated 30-year risk of CVD to be significantly higher among individuals with serious mental illnesses, at 25% compared to 11% for those without a serious mental illness.

Despite the abundance of investigation and demonstration of a clear relationship between mental health and cardiovascular diseases, patients with coronary disease, myocardial infarction, heart failure, and arrhythmias are rarely assessed for psychological distress or mental illness as a contributor to or resulting from the cardiovascular disorder.

Correlation between depression and negative lifestyle habits

Clinical depression is a common but serious mood disorder and is estimated to affect 5% of adults globally. It is also recognised by WHO to be a major contributor to the overall global burden of disease as one of the most prevalent mental health disorders. Patients with depression have shown increased platelet reactivity, decreased heart variability and increased proinflammatory markers, all of which are risk factors for CVD. As with other mood or stress related disorders, depression may also result in increased cardiac reactivity as well as heightened levels of cortisol, putting unwanted stress on the cardiovascular system. Over time, these physiological effects can lead to calcium build-up in the arteries, metabolic disease, and heart disease.

However, the greatest risk of developing CVD from depression is due to physical inactivity as a result of the fatigue, accompanied by the adoption of new and unhealthy behavioural habits. These changes in behaviour often include smoking and/or excessive alcohol consumption, a poor diet, lack of exercise, and failure to adhere to medical advice, all of which classify as CVD risk factors. In fact, smoking, poor diets high in cholesterol and/or lipids, and little regular exercise are the following leading causes for CVD after high blood pressure- which can also be affected by such lifestyle habits.

As shown in Figure 1, this relationship between the negative lifestyle habits of depression and the development of CVD is also cyclical as it creates further emotional distress which can then increase the risk of an adverse cardiac event such as blood clots or myocardial infarction, i.e. heart attacks, in patients already diagnosed with a heart disease.

Physiological distress and anxiety

Unsurprisingly, anxiety disorders are the most prevalent mental illnesses worldwide, often coming hand in hand with other mental disorders such as schizophrenia, eating disorders, and even sometimes depression. Furthermore, whilst the definition of anxiety disorders infers chronicity, anxiety and negative emotions like anger, fear, grief, and severe emotional distress, of which people suffering from mental illnesses will experience at least one, result in what is referred to as the “stress response” and can have a major impact on the cardiovascular system.

The “stress response” is triggered when mentally induced stress is detected by the limbic system and a distress signal is sent to the hypothalamus, which then sends its own signals through the autonomic nervous system to the medulla of the adrenal gland. The adrenal gland thus releases adrenaline, a catecholamine hormone, which activates the sympathetic nervous system that triggers the “flight-or-flight” response. Consequently, both pulse and blood pressure increase temporarily, leading to the constriction of arteries which may cause myocardial infarction or induce cardiac irregularities, including atrial fibrillation, tachycardia, and even sudden death. Repeated temporary increases in blood pressure may also lead to plaque disruption, resulting in myocardial infarction or strokes, and, in patients with a weakened aorta, such as those with aortic aneurysm or survivors of an aortic dissection, may lead to aortic dissection or rupture.

As the initial surge of adrenaline subsides, the hypothalamus then activates the second component of the stress response system, known as the hypothalamic pituitary adrenal (HPA) axis (see Figure 2).

The HPA axis is activated by chronic stress, causing the hypothalamus to stimulate the secretion of adrenocorticotropic hormone (ACTH) from the pituitary gland. ACTH then stimulates the adrenal gland to release another stress hormone known as cortisol. These highly increased cortisol levels cause an increase in platelet activation and aggregation which can lead to atherosclerosis. Elevated levels of cortisol may also result in high blood glucose levels, high blood pressure and inflammation, damaging the blood vessels.

Eating disorders and cardiac issues

Cardiovascular complications of eating disorders are extremely common and can be very serious. Anorexia nervosa, in particular, can be detrimental to your heart, with heart damage acting as the leading reason for hospitalisation in people with this eating disorder.

Cardiac deaths as a result of arrythmias account for approximately 50% of patient deaths with anorexia, the reason being that it involves self-starvation and intense weight loss, which not only denies the body essential nutrients to function, but also forces the body to slow down to conserve energy. The heart thus becomes smaller and weaker as it loses cardiac mass, making it more difficult to circulate blood at a healthy rate as the deteriorating heart muscle creates larger chambers and weaker walls. Consequently, bradycardia, i.e. abnormally slow heart rate of less than 60 bpm, and hypotension, i.e. low blood pressure under 90/60 mm/Hg, are extremely common in such individuals. Patients with anorexia may also experience sharp pains beneath the sternum, which could be a symptom of mitral valve prolapse occurring due to a loss of cardiac muscle mass and can improve with weight gain. However, chest pain may also be a more serious sign, indicating congestive heart failure and only has the potential to improve with proper treatment. In other forms of eating disorders, such as bulimia nervosa, the biggest cardiac risk is arrhythmia due to an electrolyte abnormality, such as low serum potassium or magnesium. The imbalance of electrolytes is caused by purging and is another factor that can put the individual at risk of heart failure. Binge eating disorders possess these same risks but also have those associated with obesity, such as hypercholesterolemia, i.e. high blood cholesterol levels, hypertension, i.e. high blood pressure, and diabetes.

Antidepressant therapy and cardiovascular considerations

Interestingly, in previous years, there has existed more concern over the cardiac complications which may arise from taking antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), than the actual cardiovascular risks of mental illnesses themselves. However, a cohort study involving 238,963 patients aged 20 to 64 years with a first diagnosis of depression between 1st January 2000 and 31st July 2011 assessed the associations between different antidepressant treatments and cardiovascular complications (Coupland, C. et al., 2016) and found that there was no evidence that SSRIs are linked with an increased risk of arrhythmia, stroke or transient ischaemic attack in people diagnosed as having depression. Furthermore, despite the beliefs of many, there was also no evidence to suggest that citalopram is associated with arrhythmia, even at high doses. Instead, the study actually found there to be some indication of a reduced risk of myocardial infarction with some of the SSRIs, particularly fluoxetine.

Conclusion

Mental distress and mental illnesses are real and can be associated with severe cardiovascular consequences. According to Von Korff, M.R. et al. (2016), as cited by Stein, D.J. et al. (2019), the odds ratios in the World Mental Health Surveys for the association of heart disease with mental health disorders were 2.1 for mood disorders, such as major depressive disorder or bipolar disorder, and 2.2 for anxiety disorders. These strong associations and inter-related causal mechanisms of mental health disorders and CVD, alongside many other NCDs, thus argue for a joint approach to care. Treatment of mental disorders should optimally incorporate attention to physical health and health behaviours, with this parallel focus on physical health beginning as early in the course of the mental disorder as possible as a primary prevention of NCDs such as CVD. It is also arguable that the mental-physical comorbidity would be better addressed by an early focus on the physical health of those with mental disorders rather than a later focus on the mental health of those