Does Cannabis Help or Hurt Sleep? Insights from a Long-Term Study
Many people use cannabis believing it helps them sleep. Researchers sought to understand whether cannabis (marijuana) use is linked to sleep quality in middle-aged adults. Researchers followed participants in a long-running U.S. health study for up to 35 years and examined both:
Lifetime cannabis use (how much cannabis people had used over many years)
Recent cannabis use (use within the past 30 days)
To measure sleep, they used:
A wearable device that tracked sleep objectively over 7 days, and
A standard questionnaire about perceived sleep quality
What the researchers found:
People who had used more cannabis over their lifetime tended to have:
Lower sleep efficiency (they spent less of their time in bed actually asleep)
More fragmented or restless sleep
More time awake after initially falling asleep
People who were currently using cannabis were also more likely than non-users or former users to:
Have poorer sleep quality based on objective measurements
Experience more nighttime awakenings
Have more fragmented sleep
Sleep longer than the typical 6–8 hour range, although longer sleep was not necessarily associated with better-quality sleep
Important limitations
The study shows an association, not proof that cannabis directly causes poor sleep.
Other factors may contribute to both cannabis use and sleep problems, even though researchers adjusted for many health and lifestyle variables
The participants were mostly around 60 years old, so the findings may not apply equally to younger adults
What this means
This study suggests while cannabis may help some individuals feel sleepy in the short term, heavier long-term use and recent use can lead to poorer sleep quality in middle age, especially when looking at objective sleep measurements.
The Article
Vu, T. T., Knutson, K. L., Auer, R., Jakob, J., Lloyd-Jones, D. M., & Carnethon, M. R. (2026). Recent and Cumulative Cannabis Use and Sleep in Middle-Aged Adults. JAMA network open, 9(10), e2638303. https://doi.org/10.1001/jamanetworkopen.2026.38303
