Sleep and circadian rhythm disruptions in anxiety and depressive disorders among adolescents and young adults

Abstract

Late adolescence and young adulthood are the periods with turbulence in which many individuals faced challenges. They experienced negative mood symptoms, sleep complaints, cognitive deficits or even anxiety and depressive disorders. Indeed, most depressive disorders and anxiety disorders were noted to have peak onsets during late adolescence and young adulthood. While existing studies on sleep complaints, and cognitive and affective functions were mostly conducted among middle-aged and older adults, three studies were conducted to enhance the understanding of anxiety and depressive disorders in late adolescence and young adulthood, with a focus on the contribution of sleep and circadian rhythm (SCR).

Study 1 was conducted among 188 adolescents and young adults (46.8% with anxiety and/or depressive disorders) to characterize the SCR in these populations. Participants completed questionnaires, sleep diary and wore an actigraph-watch to measure their SCR for five days. 187 participants continued in Study 2 and they were administered neuropsychological assessments on selected executive and basic cognitive functions for two times, separated by either a daytime sleep opportunity or wakefulness. Relationships between performance change across the assessment sessions and sleep physiology during the daytime sleep opportunity were studied. After 12 months of Study 1, 166 adolescents and young adults (42.8% with anxiety and depressive disorders) participated in Study 3. Participants were assessed on their mental health condition in the recent 12 months. The effects of SCR on depressive and anxiety disorders and the underlying psychological mechanisms were studied.

Results showed that, while adolescents and young adults already had insufficient sleep, poor sleep quality and irregular sleep-wake schedule, individuals with anxiety and depressive disorders further had comparatively worse SCR, and working memory and inhibitory control ability than healthy controls. Relationships between working memory and inhibitory control ability and mental health condition were mediated by SCR factors. In addition, a daytime sleep opportunity was found to improve working memory or protect inhibitory control ability from deterioration across time. Specific sleep physiology was found to correlate with the performance change before and after the daytime sleep opportunity. Furthermore, after adjusting for the effect of anxiety/depressive disorders, various SCR factors had direct effects on anxiety disorders and both direct and indirect effects on depressive disorders through higher level of experiential avoidance, self-blaming and lower inhibitory control ability.

Results from the three studies showed that during late adolescence and young adulthood, sleep and circadian rhythm were associated with working memory and inhibitory control ability and mental health. Those with problems in sleep and circadian rhythm might have increased chance of having worse working memory and inhibitory control ability, depressive disorders and anxiety disorders. While sleep and circadian rhythm were related to pathogenic processes underlying a range of functioning and they were mostly treatable and manageable, SCR factors should be considered as targets for prevention, assessment and intervention for adolescents and young adults.