Depression and the willingness to expend cognitive and physical effort for rewards: A systematic review.

Depression is associated with reduced motivation to engage in previously enjoyed activities. In particular, anhedonia has been linked to reduced motivation, though other depressive symptoms may also play a role. The purposes of this systematic review were to 1) examine the relationship between depression and motivation, as operationalized by a willingness to expend effort for rewards, 2) examine the relationship between anhedonia and motivation, and 3) examine potential methodological moderators of these relationships. Forty-three articles met our inclusion criteria for the review. Our review found that individuals with depression and anhedonia demonstrate reduced willingness to expend cognitive and physical effort for rewards, though the effect has been more robustly demonstrated for physical effort expenditure. Task design impacted the strength of these relationships, with stronger effects for tasks that used indices of decision-making and accuracy rather than response time. These findings have clinical implications for behavioral activation, which seeks to improve depressive symptoms by encouraging individuals to increase their activity level. Future research should examine the determinants of motivation in individuals with depression and anhedonia, to ultimately help these individuals become more active and hopefully improve their quality of life as a result.