Greater cumulative and recent recreational cannabis use may be associated with poorer objectively measured sleep quality among middle-aged adults.
Investigators analyzed data from 1,266 participants in the Coronary Artery Risk Development in Young Adults study, which initially enrolled 5,115 Black and White adults aged 18 to 30 years across 4 US sites in 1985 to 1986. Cannabis exposure was assessed repeatedly over 35 years, with sleep outcomes evaluated during the 2020 to 2022 examination. Among the participants, 891 underwent objective sleep assessments and 1,128 completed subjective sleep evaluations. The mean age of participants with objective sleep data was 60.7 years.
The investigators examined cumulative lifetime cannabis exposure, expressed in cannabis-years, and recent use within the preceding 30 days. Objective sleep was assessed using 7-day wrist actigraphy, measuring sleep duration, sleep percentage, sleep fragmentation, and wakefulness after sleep onset. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index.
After adjustment for demographic characteristics, health behaviors, comorbidities, depressive symptoms, and sleep medication use, each additional cannabis-yearwas associated with 10% higher odds of low sleep percentage, 4% higher odds of high sleep fragmentation, and 21% higher odds of prolonged wakefulness after sleep onset. Continuous analyses showed that each additional cannabis-year was associated with a 0.18–percentage-point reduction in sleep percentage, a 0.20–percentage-point increase in fragmentation, and 0.85 additional minutes of wakefulness after sleep onset.
Recent cannabis use showed similar associations. Compared with participants who had never used cannabis, those reporting use within the preceding 30 days had 4.12 times the odds of low sleep percentage, 2.46 times the odds of high sleep fragmentation, and 3.23 times the odds of prolonged wakefulness after sleep onset. Recent users also had 4.60 times the odds of sleeping more than 8 hours rather than 6 to 8 hours.
In continuous analyses, recent cannabis users slept about 20 minutes longer than never users but experienced about 11 additional minutes of wakefulness after sleep onset. Recent use was associated with a 1.74–percentage-point reduction in sleep percentage and a 2.14–percentage-point increase in fragmentation. Former users did not differ significantly from never users on objective sleep measures. Neither recent nor cumulative cannabis exposure was associated with self-reported sleep quality.
Sensitivity analyses supported the primary findings. Associations between cumulative cannabis exposure and poorer objective sleep measures persisted after excluding recent cannabis users and in analyses stratified by smoking status. No statistically significant interactions were observed by race or smoking status, whereas interactions were detected by sex, alcohol consumption, and other substance use. Associations were stronger among female participants and those who were not current alcohol drinkers. Among noncurrent drinkers, each additional cannabis-year was associated with a 0.36–percentage-point increase in sleep fragmentation vs. a 0.18–percentage-point increase among current drinkers. Associations also remained evident among participants without recent use of other substances.
Cannabis exposure was self-reported, and information on product potency, administration method, and timing relative to sleep was unavailable. Cumulative exposure estimates could not fully account for changes in cannabis potency or distinguish patterns of use over time. Objective sleep was measured during a single 7-day period at final examination, preventing assessment of longitudinal changes in sleep or the temporal relationship between cannabis exposure and sleep outcomes. Residual confounding remained possible despite extensive adjustment, and reduced participation during the COVID-19 pandemic may have introduced selection bias. The findings may not generalize to younger populations or users of contemporary higher-potency cannabis products.
The absence of corresponding associations with subjective sleep quality highlighted differences between measured and perceived sleep outcomes. However, the observational design did not establish causation. “Future longitudinal, mechanistic, and randomized studies with long-term follow-up and objective sleep assessments are needed to clarify how cannabis use relates to sleep over time,” wrote lead study author Thanh-Huyen T. Vu, PhD, of the Northwestern University Feinberg School of Medicine, and colleagues.
Full disclosures of the study authors can be found in the study.
Source: JAMA Network Open
