Sleep deprivation among adolescents and young adults is epidemic with recent evidence indicating that they maintain sleep and wake schedules with later bed times resulting in insufficient sleep. Estimates suggest that adolescents requires on average as much as 9 – 10 hours [1, 2] but approximately 45% of adolescents in the United States report obtaining less than 8 hours of sleep on school nights and similar trends have been observed among other industrialized nations . This pattern of sleep deprivation may in part be a consequence of the natural delay in the endogenous timing of sleep (i.e., circadian rhythm) occurring in the second decade of life. This shift toward an evening preference with a later bed time is consistent cross culturally and parallels the transition into puberty . Unfortunately, later bed times conflict with the early rise times typically required of adolescents and young adults to attend school or work related obligations, resulting in insufficient sleep. Later bedtimes and chronically insufficient sleep increase the risk of adolescents and young adults experiencing symptoms of depression (e.g., suicidal ideation) , excessive daytime somnolence , and engaging in risky behaviors (e.g., alcohol use and sexual activity) . Adolescents and young adults often resume their preferred sleep and wake schedules on weekends in an effort to recover from the sleep debt that accumulates during their school week, but laboratory studies indicate that this further delays the circadian timing of the sleep and wake schedule making it difficult to shift to an earlier time for the start of their school week. This mismatch between weekends and school days is referred to as circadian misalignment (i.e., ?social jet lag?) and has been associated with poor sleep quality, school absenteeism, depression, substance use and impairments in neurocognitive functioning including attention, learning, and mood regulation [8-11]. Given that circadian misalignment is often accompanied by sleep loss, it seems plausible that both sleep and circadian mechanisms may affect neurocognitive pathways regulating reward-related behavior and decision making.
The aim of this study is to characterize the influence of circadian misalignment, variability in sleep wake behavior and total sleep duration on the developmental trajectories associated with adolescent risk behavior.