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.