Rising rates of depression in today's society: consideration of the roles of effort-based rewards and enhanced resilience in day-to-day functioning.

Despite the existence of a vastly improved health care system and a multi-billion dollar antidepressant industry, the rates of depression in the US remain alarmingly high. An exploration of lifestyle changes over the past century suggests that the level of physical activity necessary to provide life's basic resources, referred to as effort-based rewards, has diminished in our industrialized, technologically advanced, service-oriented society. The evolution of the accumbens-striatal-cortical circuitry and its modulating neurochemicals in our ancestors played a significant role in sustaining the continued effort critical for the acquisition of resources such as food, water and shelter; consequently, vast reductions in the degree of physical activity required to obtain necessary resources in today's society likely lead to reduced activation of brain areas essential for reward/pleasure, motivation, problem-solving, and effective coping strategies (i.e. depressive symptomology). Comparative cultural and gender analyses reinforce the significant role of effort-based rewards in mood regulation, suggesting that minimal engagement in such endeavors leads to compromised resilience upon exposure to life's stressful challenges. If physical activity is indeed important in the maintenance of mental health, increased emphasis on behavioral and behavioral/cognitive preventative life strategies, as opposed to an emphasis on psychopharmacological strategies directed at very specific neurochemicals after the onset of depression, should be adopted as protective measures against the onset of depressive symptomology. Thus, strategies that include more global neurobiological activation in the relevant context of directed efforts provide a fresh perspective for depression research.