To Örebro University

Introduction: Developmental changes in adolescence can affect sleep patterns and increase the risk of substance use. While morning and evening chronotypes are often used to describe sleep preferences, more research is needed to understand the different chronotypes among adolescents and their connection to substance abuse. This study aims to identify the various sleep chronotypes and examine how they are linked to substance use in adolescents.

Method: A cross-sectional study was used to evaluate 1449 Swedish students aged 15–17 years (55.7% girls). We assessed adolescents' sleep quality, sleep schedule, and duration on both schooldays and weekends as a proxy for chronotype, as well as adolescents' substance use. Latent Profile Analysis (LPA) and Multinominal Logistic Regressions (MLR) were performed.

Results: Three sleep chronotypes were identified with LPA and classified as: (A) Morning chronotype (57.3%; n = 830) with an average sleep duration of 7:30 h and earlier bed and wake-up times; B) Evening chronotype (21.7%; n = 315) characterized by 6:35 h of sleep and delayed bedtimes patterns; and C) Misaligned chronotype (21%;n = 304) indicating 6:15 h of sleep along with greater social jetlag. MLR analysis showed that individuals with a Misaligned chronotype had higher odds of smoking tobacco monthly in the last year compared to the Morning chronotype and the Evening chronotype (OR = 3.28 and OR = 2.64, respectively). Likewise, those with an Evening chronotype were more likely to report monthly alcohol use than those with a Morning chronotype (OR = 1.57). No statistically significant effects were found for snus or cannabis use, nor gender as a covariate (p > 0.05).

Conclusion: The two evening chronotypes were associated with more frequent use of tobacco and alcohol in the last year. Tailoring prevention efforts for substance abuse should consider individual sleep preferences. Future studies should explore how sleep chronotypes may influence drug use and the development of dependence in adulthood.