A Preliminary Study of Central Nervous System Arousal and Sleep Quality in Bipolar Disorder

Sleep disturbances are commonly reported in patients with bipolar I disorder (BPI) and are risk factors for mood episodes. In other populations, central nervous system (CNS) hyperarousal is associated with sleep initiation and maintenance problems, and CNS hypoarousal is associated with increased sleep drive. However, it is unclear whether CNS arousal levels are a useful index of sleep disruption in BPI. This study aimed to investigate daytime CNS arousal levels in relation to perceived sleep quality in BPI. Resting EEG, mood state, and self-reported sleep quality data were collected from 34 individuals with BPI. CNS hyperarousal was associated with pervasive poor subjective sleep quality including increased sleep disturbances, increased sleep latency, and reduced global sleep quality. CNS hypoarousal was associated with greater daytime sleepiness, indicating reduced arousal. These preliminary findings suggest that CNS arousal may be a useful index for identifying individuals at high risk for relapse into a mood episode. A limitation of this study is the use of self-report instruments for sleep quality assessment. Future research should investigate the temporal relationship of CNS arousal to sleep disturbances using objective measurements of sleep quality such as polysomnography. If these findings are replicated, measures of CNS arousals may allow for identification of high-risk patients with BPI.