Young adults reported better sleep quality on days they used alcohol and cannabis together compared to alcohol-only or no-use days | Research

The takeaway

In a daily diary study of 150 young adults, simultaneous alcohol-cannabis use days were associated with better sleep quality and longer sleep duration compared to alcohol-only days, and better sleep quality compared to no-use days.

Sleep researchers, young adult health providers, substance use prevention specialists

Simultaneous use days had better sleep quality than alcohol-only, cannabis-only, and no-use days

What the researchers found

Compared to simultaneous use days, participants reported worse sleep quality and shorter sleep on alcohol-only days, earlier bedtime on cannabis-only days, and poorer sleep quality on no-use days. Those with greater alcohol problem severity reported even more pronounced differences favoring simultaneous use days. Sleep did not predict next-day simultaneous use.

Why it matters

Many young adults use substances to manage sleep. This study shows the combination may produce subjectively better sleep than alcohol alone, which could reinforce simultaneous use patterns and escalate co-use over time.

The numbers in context

150 participants, 64% female, mean age 22.09. Simultaneous use days had better sleep quality vs. alcohol-only and no-use days. Longer sleep duration vs. alcohol-only days.

How the study worked

Daily diary study of 150 young adults (64% female, mean age 22.09) completing morning smartphone surveys on prior-day substance use and previous-night sleep. Baseline alcohol and cannabis problem severity were measured. Within-person comparisons across day types.

What this study cannot tell us

Self-reported sleep measures, no objective sleep data. Within-person design cannot establish causation. Young adult sample. No assessment of sleep architecture.

How to read the evidence

Well-designed daily diary study with within-person comparisons, but reliance on self-reported sleep limits conclusions.

When this study was published

2026 publication

The bigger picture

If people sleep better when combining substances, they may escalate to more frequent co-use, potentially increasing long-term dependency risks. This reinforcement mechanism is rarely discussed in substance use prevention.

Questions still open

Does subjectively better sleep on simultaneous use days reflect actual improvements in sleep architecture? Could this reinforcement pattern drive escalation of co-use?

Common questions

Does using alcohol and cannabis together actually improve sleep?

Participants reported better subjective sleep quality, but the study did not measure actual sleep stages objectively. Perceived sleep quality may differ from physiological sleep quality.

Could this lead to more substance use?

The study raises this concern. If people consistently sleep better when combining substances, it could reinforce the pattern over time.

Read the original research

Smoke, sip, sleep, repeat: Investigating daily-level bidirectional relationships of separate and simultaneous use of alcohol and cannabis with sleep.

Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors

View on PubMed ↗Publisher’s paper ↗

Citation

Moore, Annabelle; Coelho, Sophie G; Hendershot, Christian S; Wardell, Jeffrey D. (2026). Smoke, sip, sleep, repeat: Investigating daily-level bidirectional relationships of separate and simultaneous use of alcohol and cannabis with sleep.. Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors. https://doi.org/10.1037/adb0001124