Is Obesity a Mental Health Disease?

Obesity is a public health concern with increasing prevalence. Currently, more than 68% of American adults are considered overweight and 35% are obese. (1) The majority of clinical research surrounding obesity has shown that obesity is a result of excess energy intake relative to energy expenditure. (1,2) And, although these findings are true, current clinical research suggests that the etiology of obesity is multifaceted involving not only imbalances in energy intake and energy expenditure but genetics, physiological imbalances, environmental factors, social/economical concerns, and psychological issues. (1,2) One area of interest is the role of mental health and obesity – does mental health cause obesity or does obesity cause mental health disorders? Unfortunately, the role of obesity and mental health issues is complex and not straight forward; psychopathologies can be both a cause and a consequence of obesity and in many cases, there is a bidirectional relationship. (2)

Research has shown that those with emotional issues and dysfunctional coping strategies (where effective emotional regulation is substituted by eating) may develop abnormal eating behavior that promotes weight gain. (2) While other research argues that obesity could be a risk factor for the development of depression. (3) Clinical studies looking at American adults have shown that a lifetime of anxiety and depression is associated with an increased risk of obesity. (2) In addition, the American Psychiatric Association suggests that those with atypical depression, accompanied by increased appetite and periods of overeating, are frequent in overweight and/or obese individuals.(2)

The mechanism between mental health and obesity is vast however, some research suggests that eating patterns (what people choose to eat) may be related to the brain’s reward system. (2) Nicoletti et al., discusses the role of dopamine (DA), a key neurotransmitter, as a possible contributing factor in over-eating. (4) DA is involved in the reward systems within the brain and also plays a role in influencing aspects of feeding. (4) Studies have shown that subjects with bulimia nervosa (BN) have lower dopamine metabolites in the brain compared to healthy individuals. (4) Clinical studies suggest that decreases in DA signaling can occur for many reasons including: reductions in the action of DA, reductions in dopamine receptors, or impaired DA release. Alterations within DA metabolism can impact mental health because people that do not have enough DA may not feel adequate reward sensations. (4) It is suggested that those with altered DA metabolism may rely on overeating (especially high fat foods) as a means of increasing DA levels in the brain which provides a feeling of pleasure. (4)

The above research investigates the association between obesity and mental health issues supporting the notion that obesity and mental health disorders are bi-directional – obesity can cause mental health issues and mental health issues can promote obesity. More research is warranted in the field of eating psychology if we are to fully understand the role of mental illness and weight.

1. Wright, S. M., & Aronne, L. J. (2012). Causes of obesity. Abdominal Imaging, 37(5), 730-732.

2. Lazarevich, I., Irigoyen-Camacho, M., & Velázquez-Alva, M.,del Consuelo. (2013). Obesity, eating behaviour and mental health among university students in mexico city. Nutricion Hospitalaria, 28(6), 1892-1899.

3. Tevie, J., & Shaya, F. (2015). Association between mental health and comorbid obesity and hypertension among children and adolescents in the US. European Child & Adolescent Psychiatry, 24(5), 497-502.

4. Nicoletti, C. F., Delfino, H. B. P., Ferreira, F. C., Pinhel, Marcela Augusta de Souza, & Nonino, C. B. (2019). Role of eating disorders-related polymorphisms in obesity pathophysiology. Reviews in Endocrine & Metabolic Disorders, 20(1), 115-125.

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