(PS5-9) Test of the Reward Circadian Rhythm (RCR) Dysregulation Model of Bipolar Spectrum Disorders at a Micro Time Scale: Using Ecological Momentary Assessment to Detect Event-related Social Rhythm Disruptions

Bipolar spectrum disorders (BSDs) are a group of mood disorder diagnoses across a range of severity. BSDs are present in 4-7% of the US population and are associated with clinically significant impairment as well as a large public health burden. However, the mechanisms leading to first onset and recurrence of BSD symptoms are not well understood. One theory, termed the integrated reward/circadian rhythm (RCR) dysregulation model (Alloy et al., 2015), posits that individuals high in trait reward sensitivity tend to experience greater disruption of their social rhythms (bedtime, wake time, meal time, timing of exercise, etc.) in response to reward-relevant life events. This leads to disruption of the body’s biological circadian rhythms and, ultimately, manifests in BSD symptoms. Thus, individuals high in trait reward sensitivity are at risk for BSDs. Previous longitudinal research has provided validation of this model over the course of several years. The current project sought to provide insight into the RCR model at a smaller time scale by using ecological momentary assessment (EMA). Specifically, we hypothesized that individuals high in trait reward sensitivity would experience greater social rhythm disruption (SRD) in response to reward-relevant events compared to participants with moderate reward sensitivity. To this end, a subsample of diverse participants (mean age = 21.79 years, % female = 59.7, % White = 57.4) from a longitudinal study (N=134) who were high in trait reward sensitivity (n=96; HRew) or moderate in trait reward sensitivity (n=38; MRew) completed 20 days of EMA, which included daily reporting of life events that had occurred. After the 20-day period, participants were interviewed, and interviewers who were blind to participants’ reward sensitivity group coded life events based on their effect on the reward system (reward activating or deactivating) as well as degree of SRD resulting from each event. We conducted a 2x2 ANOVA (reward group X event type) to examine the SRD resulting from each event type for both groups. The results revealed a significant interaction effect such that HRew individuals experienced greater SRD in response to both reward activating (F(1,130 = 6.50, p = .012) and deactivating (F(1,130 = 5.76, p = .018) events. Thus, our hypothesis consistent with the RCR model was supported. Even in the span of 20 days, HRew individuals exhibit greater SRD after experiencing reward-relevant events, which can manifest in onset of BSD symptoms. Thus, I will extend this project in future work to examine the full pathway from reward-relevant events to mood pathology via SRD.