3 - (IOP 3) The Relationships Between Reward-relevant Events, Social Rhythm Disruption, and Next-day Mood Symptoms in Individuals at High Risk for Bipolar Disorder: An Ecological Momentary Assessment Study

Introduction: Two prominent theoretical frameworks, the Social Zeitgeber Theory and the Behavioral Approach System (BAS)/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 the onset and course of illness. 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 with differing levels of reward sensitivity across a 20-day period.

Methods: Young adults with high (HRew) or moderate (MRew) reward sensitivity participated in a 20-day ecological momentary assessment (EMA) study. Participants reported mood symptoms three times daily and daily life events each evening and completed a life events interview on day 21. Events were coded for reward relevance and their degree of SRD. To determine whether HRew individuals experienced more reward-relevant events and associated SRD than MRew individuals, 2x2 ANOVAs were conducted. Multilevel moderated mediation was used to examine the relationships between daily reward-relevant events, SRD, and next-day depressive and hypomanic symptoms moderated by reward group.

Results: Significant interaction effects were found for both reward-activating and reward-deactivating events such that HRew individuals experienced more reward-relevant life events and associated SRD than MRew individuals. Moderated mediation analysis fully supported the Reward/Circadian Rhythm Dysregulation Model at the daily level for depressive symptoms. For hypomanic symptoms, hypotheses were partially supported such that reward-activating events predicted SRD, which, in turn, predicted hypomanic symptoms.

Discussion: These findings suggest that hypersensitivity to reward can amplify the effects of reward-relevant life events on SRD, potentially contributing to the onset of depressive symptoms in individuals with or at-risk for BSD. This study underscores the importance of considering both social rhythms and reward sensitivity in understanding BSD pathology and highlights the potential for early interventions targeting these factors.