Sleep Architecture and Risk-Taking in Adolescents and Young Adults: Independent Contributions of REM Sleep, Sigma Activity, and Morning Cortisol.

Insufficient sleep is highly prevalent among adolescents and young adults and has well-documented effects on neural systems underlying decision-making and risk-taking behavior. While prior research has linked sleep deprivation to poorer decision-making broadly, less is known about how specific features of sleep architecture contribute to risk-taking behavior, or whether the cortisol awakening response (CAR), shaped in part by the preceding night's sleep, represents an independent hormonal pathway linking sleep physiology to morning behavioral outcomes. The present study used a cross-sectional design to examine associations among objective sleep architecture, the CAR, and next-morning risk-taking behavior in a community sample of adolescents and young adults. We predicted that (1) greater rapid eye movement (REM) sleep percentage would be associated with better overall task performance, and (2) greater N2-N3 sigma power would be associated with reduced risk-taking under uncertainty. The role of the CAR was examined exploratorily. Fifty-five adolescents and young adults (aged 15-34; mean age = 18.9 years, SD = 3.08 years, 86% female) completed overnight sleep monitoring using a wearable EEG device, provided morning saliva samples to index the CAR (n = 28), and completed the Balloon Emotional Learning Task (BELT) to assess risk-taking behavior. Primary sleep variables of interest included REM sleep percentage and Non-REM sleep (N2-N3) sigma power. Behavioral outcomes included overall task performance and risk-taking under uncertainty. Linear regression models with age as a covariate were used for all primary analyses. Higher REM sleep percentage was associated with greater overall task performance, while higher N2-N3 sigma power was associated with reduced risk-taking under uncertainty, consistent with predictions. Greater CAR was independently associated with poorer task performance but did not moderate sleep-behavior associations, nor was it significantly associated with objective sleep measures. These findings highlight the stage-specific contributions of sleep architecture to next-morning risk-taking behavior in adolescents and young adults, with sleep physiology and cortisol responsivity emerging as distinct physiological contributors to behavioral outcomes.