Using Ambulatory Assessments to Examine the Interplay Between Sleep Misperception and Emotion-Based Impulsivity

Abstract

Background: Sleep disruptions are hypothesized to be an etiological factor in bipolar disorder (BD), and may exacerbate affective, cognitive, and behavioral dysregulation in BD. However, few studies to our knowledge have examined the discrepancy between subjective and objective total sleep time (sleep misperception) in BD and its clinical implications. Objectives: The goals of this study were to: 1) investigate whether individuals with subclinical or clinical BD experience higher levels of sleep misperception, 2) determine whether sleep misperception increases severity of a core feature of BD, emotion-based impulsivity (EBI), and 3) explore how the direction of sleep misperception (i.e., overestimating or underestimating total sleep time) may impact EBI. Methods: In a preliminary sample, 26 healthy controls and 42 individuals with subclinical and clinical bipolar disorder completed ecological momentary assessments (EMA) assessing EBI and subjective sleep over a period of 28 days. Additionally, participants' sleep was objectively assessed by validated Fitbit Charge 5 trackers. Sleep misperception was calculated by finding the absolute difference between subjective and objective total sleep time. Directionality of sleep misperception (i.e., overestimating or underestimating total sleep time) was coded dichotomously. Results: To assess the relationship between objective and subjective total sleep time with the assumption that the correlation is non-zero, we used a Bayes factor test for linear correlations and found a moderate association (R = 0.46, 95% MDI =[0.44, 0.48]). Bayesian mixed effects model (allowing for random intercepts) found that those with BD have on average approximately 30 minutes more of sleep misperception than healthy controls (95% CI [9.09, 47.36]). Logistic regression models covarying for age, sex, diagnosis, and depression found that models of EBI with sleep misperception had strong evidence of better model fit than models including subjective or objective total sleep time as predictors (Bayes factor >10). While the absolute magnitude of sleep misperception was negligible in predicting next-day EBI (r = 0.00, p = 0.00), overestimating total sleep time was associated with a 13% decrease in the odds of next-day EBI (p = 0.03). Conclusions: Findings and future directions will be discussed, disentangling the mechanisms of sleep misperception and emphasizing how mixed-methods of ambulatory assessments (EMA and Fitbit) can be used to examine the bidirectional relationship between sleep and BD symptoms.