Mounting evidence indicates that delayed sleep phase (DSP) may confer risk for adolescent substance use (SU) and SUDs. However, the exact nature of this link and the mechanisms underlying it remain unclear. Circadian misalignment, a mismatch between late sleep hours and early school start times, is a compelling potential contributor to elevated SU in adolescent DSP with plausible neurobehavioral mechanisms. The investigators hypothesize that DSP-associated circadian misalignment decreases impulse control and increases reward sensitivity, thereby increasing SUD risk.~This study will, for the first time, (1) comprehensively characterize the SUD risk profile associated with adolescent DSP, and (2) probe whether SUD risk is diminished by altering sleep/circadian timing. The study will assess both established markers of SUD risk and putative neurobehavioral mechanisms (impulsivity and reward sensitivity). Specifically, the investigators will employ a comprehensive, multi-method approach to examining DSP's role in SUD risk, combining laboratory, experimental, and longitudinal studies. The investigators will recruit a sample of 150 eleventh and twelfth graders (16-19 y/o), divided between 100 DSP and 50 normal phase teens. The investigators will focus on cannabis and alcohol use given their prevalent use in adolescents and evident links to DSP.~In the experimental study, the investigators will probe whether stabilizing circadian phase in the DSP group (n=100) by using sleep scheduling and chronotherapeutic approaches (i.e., dim light in the evening and bright light in the morning) improves sleep and neurobehavioral function relevant to SUD risk.
This study will (1) comprehensively characterize the substance use disorder (SUD) risk profile associated with adolescent Delayed Sleep Phase (DSP), and (2) probe whether SUD risk is diminished by altering sleep/circadian timing.