Effects of cannabis use timing and formulation on sleep among young adults who report high-intensity alcohol use

Background: Young adults who use alcohol and cannabis often report sleep problems, which contribute to myriad mental health disorders. Cannabis is often used for sleep despite scant evidence supporting its efficacy. Distinct cannabis formulations (e.g., flower, edibles) have varying potencies, and when they are used may partially explain discrepancies between cannabis’ perceived and demonstrated impact on sleep. This study tested the hypotheses that using (1) cannabis closer to bedtime (regardless of formulation), and (2) less potent formulations (flower or edibles vs. concentrates), would predict better nightly sleep. Further, given rapid tolerance to cannabis’ somnolent effects, we explored if more problematic cannabis use (on the Cannabis Use Disorder Identification Test [CUDIT]) moderated these associations.

Methods: Young adults (N=137; M [SD] age=22 [3] years, 54% Female; 75% Non-Hispanic White) with past-month high-intensity alcohol use (8+/10+ drinks for females/males) completed the CUDIT and 28 days of ambulatory assessment. Participants reported on prior-day alcohol/tobacco use and sleep (bed/wake times, subjective quality) each morning and self-initiated real-time cannabis reports (timestamped) indicating which formulation (flower, edible, concentrate) was used. Multilevel models tested cannabis use timing and formulation effects on sleep quality and duration, and interactions with CUDIT cut-offs (non-hazardous use [< 8]; hazardous use [8-11]; possible CUD [12+]). Analyses controlled for age, sex, study day, weekday/end, and day-level alcohol/tobacco use.

Results: Over half of the sample met criteria for either hazardous cannabis use (n=25, 18%) or possible CUD (n=46, 34%). On average, participants used cannabis on 10 (SD=8) days, with last daily sessions taking place 5 (SD=3) hours before bedtime. Using cannabis (regardless of formulation) closer to bedtime was associated with better sleep quality for participants with hazardous use or possible, but worse sleep quality for those with non-hazardous use (p<.05). Neither cannabis formulation, nor its interaction by CUDIT group, predicted daily sleep quality. Longer sleep durations were predicted by days with either edible (vs. flower) use or cannabis use (regardless of formulation) occurring closer to bedtime (ps<.05), and these effects were not moderated by CUDIT group.

Conclusions: This study addressed how cannabis use timing and formulation impacted sleep, and if relations differed for young adults based on level of baseline cannabis use. Public health initiatives can use these findings to craft messages about cannabis and sleep, and results may help clinicians to educate patients on how cannabis timing and formulation impacts sleep. More research needs to determine how cannabis affects sleep among older individuals and adults from more diverse backgrounds. Future research should also investigate how different cannabis quantities affect self-reported and objective sleep phenotypes.