Recent and Cumulative Cannabis Use and Sleep in Middle-Aged Adults

Importance Cannabis is widely used and often promoted as a sleep aid, but evidence of its long-term implications for sleep is limited. Objective To examine the associations of cumulative cannabis exposure from young adulthood to middle age and recent cannabis use with objective and subjective sleep outcomes in middle age. Design, Setting, and Participants This cohort study analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, including 35 years of follow-up through the year-35 examination (conducted in 2020 to 2022), and the CARDIA Year-35 Sleep Ancillary Study. Analyses were conducted from January 15 to July 15, 2026. Exposures Cumulative cannabis use (calculated in cannabis-years, with 1 cannabis-year equating to 365 days of use) and recent cannabis use (defined as past 30-day use vs former use and never use). Main Outcomes and Measures Objective sleep was assessed using data from 7-day wrist actigraphy, and subjective sleep was assessed with the Pittsburgh Sleep Quality Index (PSQI). Primary outcomes and measures were objective sleep duration (categorized as short [<6 hours], optimal [6-8 hours], or long [>8 hours]), sleep percentage (defined as percentage of time asleep; low percentage: <85%), sleep fragmentation (defined as the index of restlessness during sleep; high fragmentation: highest quartile), and wakefulness after sleep onset (WASO; prolonged WASO: ≥30 minutes) and subjective sleep quality (PSQI score and poor sleep quality: PSQI >5). Results A total of 1266 participants (891 with objective and 1128 with subjective sleep data) were analyzed. Among the 891 participants with objective sleep data, the mean (SD) age at the year-35 examination was 60.7 (3.6) years; the cohort included 564 females (63.3%) and 365 Black (41.0%) and 526 White (59.0%) participants. After multivariable adjustment, each additional cannabis-year was associated with higher odds of low sleep percentage (odds ratio [OR], 1.10; 95% CI, 1.06-1.14), high sleep fragmentation (OR, 1.04; 95% CI, 1.01-1.08), and prolonged WASO (OR, 1.21; 95% CI, 1.10-1.34). Compared with participants with former use and never use status, those with recent use had higher odds of low sleep percentage, high fragmentation, prolonged WASO, and long (vs optimal) sleep duration (eg, vs never use, prolonged WASO: OR, 3.23 [95% CI, 1.44-7.27]; long sleep duration: OR, 4.60 [95% CI, 1.81-11.70]). Cannabis use was not associated with subjective sleep quality. Conclusions and Relevance In this cohort study, both cumulative use and recent cannabis use were associated with poorer objective sleep quality, although no association with self-reported sleep quality was found. These findings underscore the importance of assessing both subjective and objective sleep and suggest potential adverse association between long-term recreational cannabis exposure and midlife sleep health.