Test of the reward/circadian rhythm dysregulation model of risk for bipolar spectrum disorders at a micro time scale using multilevel moderated mediation.

Two theories, the social zeitgeber theory and the reward theory, have been proposed to explain the onset of bipolar spectrum disorders (BSDs), highlighting the roles of disrupted sleep-wake rhythms and hypersensitivity to reward in BSDs. This study tested a component of the integrated reward/circadian rhythm dysregulation model of BSDs by examining how reward-relevant life events predict affective symptoms via social rhythm disruption (SRD) in young adults (N = 145) with high- or moderate-reward sensitivity across 20-days of ecological momentary assessment. Significant interaction effects were observed such that high-reward individuals experienced more reward-relevant life events and associated SRD. Moderated mediation analysis supported the integrated model at the daily level for depressive symptoms. For hypomanic symptoms, there was not a significant indirect effect nor moderation by reward group. Findings suggest hypersensitivity to reward amplifies the effects of reward-relevant life events on SRD, contributing to the onset of depressive symptoms in individuals at-risk for BSD. Results highlight potential early intervention targets. (PsycInfo Database Record (c) 2026 APA, all rights reserved).