The effect of poor sleep quality on mood outcome differs between men and women: A longitudinal study of bipolar disorder

Abstract Background Sleep disturbance is bi-directionally related to mood de-stabilization in bipolar disorder (BD), and sleep quality differs in men and women. We aimed to determine whether perception of poor sleep quality would have a different effect on mood outcome in men versus women. Methods We assessed association between sleep quality (Pittsburgh Sleep Quality Index (PSQI)) at study intake and mood outcome over 2 years in subjects from the Prechter Longitudinal Study of Bipolar Disorder (N=216; 29.6% males). The main outcome measure was the severity, variability, and frequency of mood episodes measured by self-report over 2 years of follow-up. Multivariable linear regression models stratified by sex examined the relationship between PSQI with mood outcomes, while age, stressful life events, mood state and neuroticism at baseline were controlled. Results In women, poor sleep quality at baseline predicted increased severity (B=0.28, p<0.001) and frequency of episodes (B=0.32, p<0.001) of depression, and poor sleep quality was a stronger predictor than baseline depression; poor sleep quality predicted increased severity (B=0.19, p<0.05) and variability (B=0.20, p<0.05) of mania, and frequency of mixed episodes (B=0.27, p<0.01). In men, baseline depression and neuroticism were stronger predictors of mood outcome compared to poor sleep quality. Limitations We measured perception of sleep quality, but not objective changes in sleep. Conclusions In a longitudinal study of BD, women reported poorer perceived sleep quality than men, and poor sleep quality predicted worse mood outcome in BD. Clinicians should be sensitive to addressing sleep complaints in women with BD early in treatment to improve outcome in BD.