Study: Cannabis Use Leads to Longer Sleep, But Effects Vanish With Alcohol

The study, conducted by researchers at Notre Dame University, the University of Missouri, and the University of Colorado, tracked 48 adults over a 60-day period using daily assessments of substance use and sleep patterns. Participants reported weekly alcohol and/or cannabis use. Cannabis use alone was linked to slightly longer sleep duration compared to days when participants drank alcohol, used both substances, or abstained. However, cannabis did not improve reported sleep quality, just the overall length of sleep. When combined with alcohol, the additional sleep benefit was lost.

The researchers also found that longer sleep duration was associated with a higher likelihood of cannabis use the following day, suggesting a cycle that could contribute to more frequent consumption over time. Sleep quality and duration were not tied to cravings for alcohol or cannabis.

The findings point to at least mild sleep benefits from marijuana, while reinforcing evidence that alcohol disrupts rest.