Subjective and objective sleep discrepancy in symptomatic bipolar disorder compared to healthy controls

Background: Bipolar disorder (BD) is associated with sleep misperception. The objective of this study was to investigate the correlation between subjective and objective measures of sleep in persons with symptomatic bipolar disorder (BDS) compared to healthy controls (HC). Methods: We studied 24 BDS and 30 HC subjects similar in age, race and sex. Subjective sleep was measured with Pittsburgh Sleep Quality Index (PSQI) and objective sleep with 7-days of actigraphy. Absolute discrepancy variables were calculated by subtracting objective sleep latency (SL) and total sleep time (TST) on actigraphy from their respective subjective estimates from PSQI. Mood symptoms were measured with Young Mania Rating Scale and Hamilton Depression Rating Scale. Results: In the BDS group, subjective TST did not significantly correlate with objective TST, while it correlated in the HC group. The BDS group had significantly higher absolute discrepancy between subjective and objective SL and TST compared to the HC group. Multivariable regression analysis showed that severity of depression was associated with greater absolute discrepancy between subjective and objective TST within the BDS group. Limitations: Subjects are from a tertiary care center and were on medications for treatment of BD symptoms. Conclusion: There is low correlation between subjective and objective TST in BDS subjects and more severe depressive symptoms are associated with greater absolute discrepancy in TST. Objective rather than subjective measures of sleep, such as actigraphy, may be needed to evaluate sleep in BD subjects. Cognitive-behavioral interventions to address sleep misperception and associated depressed mood may be indicated in BD.