Background: Altered reward processing is postulated to be a feature of depression. Reward processing may be valuable to understanding early-onset depressive disorders, which tend to be chronic and recurrent.
Methods: Reward-related decision making was examined within a longitudinal study of 221 11-year-old boys, 25 of whom had a depressive disorder at age 10 or 11. Participants completed a behavioral decision-making task involving varying probability and magnitude of obtaining reward.
Results: Under conditions involving a high probability of winning, boys with depression failed to distinguish between options involving small or large possible reward. Boys with anxiety or externalizing disorders at age 10 or 11 did not differ from others in their reward-related decisions. Low frequency of choosing the high-probability, large reward option at age 11 predicted depressive disorders, anxiety disorders, and depressive symptoms 1 year later. Furthermore, reward-related decisions predicted later depressive or anxiety disorders even when adjusting for the continuity of such disorders and the presence of concurrent externalizing disorders.
Conclusions: Findings are consistent with affective neuroscience models of altered reward processing and diminished positive affect in depression. This study represents a step toward elucidating the motivational and emotional aspects of early-onset depression.