Abstract
BACKGROUND: Sleep-promotion is one of the most common reasons people use cannabis. Previous studies, primarily among young adults, suggest that cannabis use has negligible day-level effects on sleep but may attenuate alcohol's negative effects when both substances are used. Studies among middle-aged/older adults are needed to determine the generalizability of these day-level associations. METHODS: This preregistered secondary data analysis examined daily-life associations between alcohol and cannabis use with next-day sleep quality and duration in a community sample of 48 adults (50 % female; age M=36.42, SD=10.96) reporting weekly alcohol and/or cannabis use. Participants completed ecological momentary assessments over 60 days. Multilevel models examined whether alcohol use, cannabis use, or alcohol-cannabis co-use (vs. no use) that day were associated with sleep quality and duration that night. Next, sleep quality and duration were examined as predictors of next-day craving and alcohol/cannabis use. RESULTS: Cannabis use was associated with longer sleep duration than days of alcohol use, co-use, or no use, which were not different from one another. Sleep quality did not differ following alcohol/cannabis use. Sleep quality and duration were not associated with next-day craving for alcohol or cannabis. Longer sleep duration was associated with higher likelihood of next-day cannabis use. CONCLUSIONS: Community adults report sleeping ~15min longer on days of cannabis use, unless they also drank alcohol that day. This finding underscores the importance of examining co-use in daily life. Cannabis use demonstrated limited benefits for sleep, which should be evaluated in context with risk for increasing cannabis use over time.