Exercise is medicine for patients with major depressive disorders: but only if the “pill” is taken!

Major depressive disorders (MDDs) are a widespread and burdensome mental illness associated with a high comorbidity with other conditions and a significantly reduced life expectancy compared to the general population. Therefore, targeted actions are needed to improve physical health in people with MDDs, in addition to ongoing efforts to enhance psychological well-being. Meanwhile, the positive effects of exercise training on the treatment of MDDs are well documented, while compelling evidence exists that exercise interventions can improve cardiorespiratory fitness in clinically meaningful ways. On the flipside, the long-term effects of exercise therapy are still not well documented, and recent studies suggest that initial improvements in MDDs dissipate if regular exercise participation is discontinued after the end of interventions. A recent survey among Swiss psychiatric hospitals further shows that all institutions provide some form of physical activity and exercise program. However, only a limited number of patients participate in these programs, mainly because participation is voluntary and no particular efforts are undertaken to engage patients with the lowest physical activity levels. We argue that more systematic efforts are needed to fully exploit the potential of physical activity and exercise programs in psychiatric care. We also emphasize that initiating and maintaining regular physical activity among psychiatric patients is a major challenge because specific dysfunctional cognitive–emotional processes might interfere with their capacity to self-regulate health-related behaviors. Specifically, we claim that behavioral skill training should be used to support patients with MDDs in overcoming barriers to initiating and maintaining physical activity. Moreover, we suggest that the assessment of physical activity and cardiorespiratory fitness should become routine in psychiatric practice.