An Integrated Sleep and Reward Processing Model of Major Depressive Disorder

• Published in: Behavior therapy 2020-07, Vol.51 (4), p.572-587
• Main Authors: Boland, Elaine M., Goldschmied, Jennifer R., Wakschal, Emily, Nusslock, Robin, Gehrman, Philip R.
• Format: Article
• Language: English
• Subjects: depression; Depressive Disorder, Major; Humans; Reward; reward processing; Sleep; sleep disturbance; Sleep Wake Disorders
• ISSN: 0005-7894; 1878-1888
• DOI: 10.1016/j.beth.2019.12.005

Major depressive disorder with comorbid sleep disturbance has been associated with negative outcomes, including lower rates of treatment response and a greater likelihood of depressive relapse compared to those without sleep disturbance. However, little, if any, research has been conducted to understand why such negative treatment outcomes occur when sleep disturbance is present. In this conceptual review, we argue that the relationship of sleep disturbance and negative treatment outcomes may be mediated by alterations in neural reward processing in individuals with blunted trait-level reward responsivity. We first briefly characterize sleep disturbance in depression, discuss the nature of reward processing impairments in depression, and summarize the sleep/reward relationship in healthy human subjects. We then introduce a novel Integrated Sleep and Reward model of the course and maintenance of major depressive disorder and present preliminary evidence of sleep and reward interaction in unipolar depression. Finally, we discuss limitations of the model and offer testable hypotheses and directions for future research. •Sleep disturbance is associated with poor depression treatment outcome.•The mechanisms underlying this relationship are poorly understood.•Reward processing is impaired in depression and may be affected by sleep disturbance.•The interaction of these two domains may impair depression recovery.•An integrated model may explain poor outcomes in the presence of sleep disturbance.