Anhedonia sub-components and reward and effort learning for primary and secondary rewards in young people with depression symptoms

Abstract

Background: Anhedonia, a central depression symptom, is associated with impairments in reward processing. However how the sub-components of reward processing (anticipation, motivation, consummation and learning) are related to depression symptoms is not well understood. In particular, little is known about how effort cost and reward learning is related to anhedonia.Methods: We recruited young people with high (N=50) and low (N=88) depression symptoms and assessed their learning, consummatory, anticipatory, and motivational responses within an effort and reward learning task. To increase the reward attractiveness, especially for younger people, we included not only money (secondary reward), but also chocolate tastes and puppy images (primary rewards).Results: Across all participants, we found that self-reported willingness to exert effort positively correlated with actual effort exertion and negatively with effort completion times. We also observed higher accuracy for reward learning vs. effort learning. Additionally, effort expenditure differed between reward types, although no differences in reward liking were observed. Interestingly, we also found that higher anticipatory anhedonia was associated with lower reward learning accuracy. Limitations: The study assessed only depressive symptoms, not clinically diagnosed major depression. Conclusion: To our knowledge, this is the first study to examine reward and effort learning simultaneously in young people with depression symptoms. Our findings suggest a differentiation between motivational and consummatory responses, as well as between reward and effort learning. Moreover, we show that anticipatory anhedonia is related to reward learning. Understanding the link between objective reward processing and anhedonia sub-types could provide new targets for treatment development.