LAUSR

STUDY OBJECTIVES This study examined longitudinal associations of sleep problems with alcohol and cannabis use across six annual waves of data from adolescence to emerging adulthood. METHODS Participants were 3,265 youth from California (ages 16 to 22 across waves). At each wave, past-month alcohol use and cannabis use, mental health, and several dimensions of sleep health (i.e., social jetlag, bedtimes, time in bed, trouble sleeping) were assessed via questionnaire. Parallel process latent growth models examined the association between sleep and alcohol or cannabis use trajectories and the role of mental health in contributing to such trajectories. RESULTS Smaller declines in social jetlag (r = .11, p = .04), increases in trouble sleeping (r = .18, p < .01), and later weekday (r = .16, p < .01) and weekend bedtimes (r = .25, p < .01) were associated with increases in likelihood of alcohol use over time. Declines in weekend TIB (r = -.13, p = .03), as well as increases in weekday TIB (r = 0.11, p = 0.04) and later weekday (r = .18, p < .01) and weekend bedtime (r = .24, p < .01), were associated with increases in likelihood of cannabis use over time. Most associations remained significant after controlling for time-varying mental health symptoms. CONCLUSIONS Trajectories of sleep health were associated with trajectories of alcohol and cannabis use during late adolescence to emerging adulthood. Improving sleep is an important target for intervention efforts to reduce the risk of substance use during this critical developmental transition.