1089 SLEEP AND AUTONOMIC STRESS RESPONSE IN ADOLESCENTS WITH BIPOLAR DISORDER

Abstract

Introduction: Sleep and circadian disruption contribute to the pathophysiology of bipolar illness, but the mechanisms of this relationship are not yet understood. The aim of the present research was to evaluate whether sleep duration and timing in adolescents with bipolar disorder would prospectively predict parasympathetic nervous system activity to a social stressor, reflecting interference in stress regulatory systems that may confer vulnerability to mood episodes. Methods: Participants were euthymic or depressed adolescents with bipolar disorder (n=24) and healthy controls (n=27). Sleep duration and timing were measured by actigraphy for a week prior to a laboratory social stress task, and electrocardiography was used to index stress-related high frequency heart rate variability (HRV). Multilevel models were performed to evaluate the effects of study group, sleep characteristics, and their interaction on initial HRV and change in HRV during stress and recovery. Results: There was a significant interaction between study group and mean sleep duration on initial HRV (Z=-3.22, p=.001) and linear and quadratic change in HRV during the stressor (respectively, Z=2.47, p=.01; Z=2.41, p=.02). Longer sleep durations were associated with lower initial HRV and greater reactivity (slopes) in HRV during the stressor in adolescents with bipolar disorder but not controls. Sleep midpoint did not moderate the effect of group on initial HRV, but there was a significant interaction between group and sleep midpoint on linear and quadratic change in HRV during the stressor (respectively, Z=-2.26, p=.02; Z=2.01, p=.04). Conclusion: These results suggest that long sleep duration, which is characteristic of both remitted and depressed episodes of bipolar illness, is associated with stress vulnerability in adolescents with bipolar disorder. In the context of research linking insufficient sleep to mood impairment in typical adolescents, these data highlight the differential vulnerability that long sleep duration may import for adolescents with bipolar illness.