Psychotropic medication use mediates the relationship between mood and anxiety disorders and obesity: findings from a nationally representative sample.

Growing evidence points to a relationship between obesity and both mood and anxiety disorders, but the question of what accounts for this association remains unanswered. The present study examined the use of psychotropic medications as a mediator of the mood/anxiety disorder-obesity relationship. Data came from the public use dataset of the Canadian Community Health Survey Cycle 1.2 (age 15 years and older, N = 36,984). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychiatric diagnoses of 12-month mood disorders (e.g., major depressive disorder, mania) and anxiety disorders (e.g., panic attacks, panic disorder, social phobia, agoraphobia) were examined as was use of psychotropic medications (e.g., antidepressants, antipsychotics, anxiolytics, hypnotics, mood stabilizers) and obesity (defined as body mass index ≥30). A series of multiple logistic regression analyses were completed to test study hypotheses. Covariates in these analyses included sociodemographic factors, physical activity, and physical illness burden. The use of two medication classes, namely antidepressants and antipsychotics, emerged as significant predictors of obesity as well as mediators of the psychiatric diagnosis-obesity relationship after evaluating all psychotropic medication classes simultaneously, while also controlling for other theoretically relevant variables. The use of these two medications accounted for 86% of the relationship between mood disorders and obesity and 32% of the relationship between anxiety disorders and obesity. The study findings guide advances in the theoretical conceptualization of the mechanisms involved in mood/anxiety disorder-obesity relations. Clinical implications are discussed.