Poor Sleep as a Pathophysiological Pathway Underlying the Association between Stress Exposure and the Diurnal Cortisol Profile in Children and Adolescents

ii iii ABSTRACT Poor Sleep as a Pathophysiological Pathway Underlying the Association between Stress Exposure and the Diurnal Cortisol Profile in Children and Adolescents Jinshia Ly There is increasing evidence supporting the potential contribution of poor sleep as a pathophysiological pathway underlying the association between stress exposure and disruption of the diurnal cortisol profile. Specifically, convincing evidence shows that stress exposure leads to poor sleep, which, in part, is responsible for subsequent disruption of the diurnal cortisol profile. The overarching objective of the present study was to examine whether poor sleep mediates the relation between stress exposure and the diurnal cortisol profile in children and adolescents. 55.90% males). Participants' salivary cortisol was sampled over two days to derive single sample (bedtime cortisol, maximum cortisol) and aggregate cortisol indices (AUC AG , AUC I , AUC TG , slope max). Youth-report of stressful life events and daily hassles were obtained. Subjective reports of sleep duration and sleep quality were obtained by youth-and parent-report measures. Greater stressful life events were associated with elevated AUC AG and AUC TG. Greater daily hassles were associated with elevated maximum cortisol, AUC AG , AUC TG , and steeper slope max. Greater stressful life events and daily hassles were associated with poorer sleep quality, which, in turn, was related to higher bedtime cortisol and AUC TG. Mediational analyses revealed that the sleep quality mediated the association between stress exposure and AUC TG. iv The present study provided evidence for poor sleep as a potential pathophysiological pathway underlying the effects of stress exposure on the diurnal cortisol profile in children and adolescents. The current research findings have important implications and help reframe prevention efforts and public policies aimed at reducing the physiological sequelae of stress exposure. Future research should replicate current findings using objective measures of sleep to better understand specific sleep parameters that underlie the association between stress exposure and the diurnal cortisol profile. v ACKNOWLEDGEMENT