Mixing cannabis with alcohol and tobacco takes a toll on sleep

For many people, cannabis has become a part of their sleep routine—a way to relax and ease into sleep at the end of the day. But a new study from researchers at the Oregon Institute of Occupational Health Sciences at OHSU found evidence that individuals who use cannabis, alcohol and tobacco contemporaneously, though not necessarily at the same time, experience measurably worse sleep health than those who use cannabis alone.

The paper, “Associations of cannabis. Alcohol, and tobacco use combinations with sleep health,” was recently published in the journal Addictive Behavior Reports. The research team surveyed 518 adults across the United States who reported regular cannabis use for the study. Participants answered questions about their consumption of alcohol and cigarettes alongside cannabis use and completed three standardized clinical surveys measuring sleep quality, insomnia severity, and daytime sleepiness.

The researchers sorted participants into four groups: cannabis only, alcohol and cannabis, cigarettes and cannabis, and polysubstance use — meaning all three substances. Nearly half the individuals in the sample used cannabis alongside alcohol, and about one in five used all three. Only a quarter used cannabis exclusively.

The polysubstance group fared worse on every measure. Compared to cannabis-only users, those who used all three substances scored significantly worse on the sleep quality and insomnia surveys and were more than twice as likely to meet the threshold for moderate or severe insomnia. They also reported worse subjective sleep quality and lower satisfaction with their sleep patterns overall.

According to OccHealthSci Assistant Professor and co-author Nicole Bowles, sleep quality, satisfaction, and health were most impaired by polysubstance use.

The study also found that more hazardous cannabis use — measured using a validated screening tool for cannabis use disorder — independently predicted worse global sleep quality and greater daytime sleepiness, suggesting that heavier cannabis use carries its own sleep costs, separate from any influence of other substances.

There are limitations to the study, according to the study lead author, post-doctoral scholar Dr. David Reichenberger. Its cross-sectional design prevents conclusions about cause and effect, and all participants used cannabis specifically for sleep complaints, making the results less generalizable.

Still, the findings carry a message for clinicians: assessing sleep health and substance use together, rather than in isolation, may reveal patterns that neither domain alone would expose. As cannabis use continues to rise and polysubstance use becomes more common, understanding their combined effects on something as fundamental as sleep becomes increasingly urgent.

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This work was supported by National Heart, Lung, and Blood Institute (NHLBI) NIH grants K01 HL151745, R35 HL155681, the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, through Grant Award Number UL1TR002369, and the Oregon Institute of Occupational Health Sciences at Oregon Health & Science University via funds from the Division of Consumer and Business Services of the State of Oregon (ORS 656.630). DAR was supported by T32 HL166128.