Reward System in Late-Life Depression: a Cross-Sectional Case-Control Study

Abstract

Objective: Anhedonia, commonly defined as a reduced ability to feel pleasure, is a core clinical symptom of late-life depression (LLD). Deficits in reward processing are hypothesised to be associated with anhedonia. We examined differences in reward sensitivity between patients with LLD and healthy controls and explored the associations between LLD-related symptomatology, global cognition, and the reward system. Methods: The reward responsiveness of 63 patients with LLD and 58 healthy controls aged ≥60 years was assessed using the probabilistic reward learning task with an asymmetric reward schedule. Results: Compared with healthy controls, patients with LLD displayed lower response bias and reward learning. Global cognition of all participants was positively correlated with response bias. In patients with LLD, anhedonia severity explained impaired reward learning. Conclusion: A deficit in reward processing is implicated in patients with LLD. Our findings suggest that executive dysfunction and anhedonia contribute to lower sensitivity to reward learning in patients with LLD.