Summary:
A 35-year longitudinal study that followed adults from young adulthood into middle age found that both cumulative lifetime and recent cannabis use are linked to poorer objectively measured sleep. Wrist actigraphy showed lower sleep efficiency, greater sleep fragmentation, and longer wake periods after sleep onset. Notably, study participants generally did not report worse sleep subjectively, revealing a disconnect between measured sleep disruption and perceived sleep quality.
Key Facts:
- Objective disruption versus subjective perception: Wrist actigraphy detected reduced sleep efficiency, increased fragmentation, and prolonged awakenings among cannabis users, while self-reported sleep questionnaires did not reflect these disturbances.
- 35-year cohort study: Analysis of 1,266 Black and White adults from the CARDIA study demonstrated that higher cumulative cannabis exposure across decades correlates with degraded sleep architecture in midlife.
- Associations independent of common confounders: The relationship between cannabis use and poorer objective sleep persisted after adjusting for age, sex, race, alcohol and tobacco use, physical activity, depressive symptoms, and other medication or substance use.
Source: Northwestern University
Many adults use cannabis products, tinctures, or edibles believing THC and other cannabinoids help them fall asleep or stay asleep. However, a major long-term study led by researchers at Northwestern Medicine suggests that cannabis exposure over time may harm sleep quality—even when users remain unaware of the changes.
Published in JAMA Network Open, the study found that both cumulative lifetime cannabis use and recent consumption were associated with poorer objective sleep measures in middle age. At the same time, participants’ self-reports did not indicate worse sleep, highlighting an “illusion” of restorative sleep among cannabis users.
Tracking Sleep Quality Across Three and a Half Decades
Researchers examined data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a racially diverse cohort that began in 1985–1986 and has followed participants through the present. Cannabis use was repeatedly recorded across nearly 35 years as participants moved from young adulthood into middle age.
At the year-35 examination, 1,266 participants took part in the sleep ancillary study. Of those, 891 wore wrist actigraphy devices for seven consecutive nights to capture objective sleep metrics while 1,128 completed the Pittsburgh Sleep Quality Index (PSQI) to report subjective sleep experiences. This parallel measurement allowed direct comparison between physiological sleep data and personal sleep perceptions.
Actigraphy indicated that participants with greater cumulative cannabis exposure spent a smaller proportion of the night asleep (lower sleep efficiency), woke more frequently (higher fragmentation), and experienced longer wakefulness after initially falling asleep. Recent cannabis users showed similar patterns and were also more likely to sleep longer than eight hours per night—an indicator often associated with nonrestorative or hypersomnolent sleep.
The Subjective Disconnect
Despite clear objective sleep disturbances, people who used cannabis did not rate their sleep as worse than non-users on clinical questionnaires. This mismatch between measured sleep architecture and self-reported sleep quality was a striking finding of the study.
“This was one of the most interesting findings,” said corresponding author Thanh-Huyen T. Vu, MD, PhD, research associate professor of preventive medicine at Northwestern University Feinberg School of Medicine. “Wearable devices detected greater nighttime disruption among participants with long-term cannabis exposure, but the participants themselves generally did not report worse sleep.”
The discrepancy suggests cannabis can produce sedation or blunt awareness of awakenings while still disrupting the micro-architecture that supports restorative sleep. These effects may undermine sleep quality even when subjective feeling of sleepiness or restfulness appears unchanged.
Importantly, associations between cannabis use and objective sleep measures remained after controlling for a wide range of potential confounders, including demographic factors, depressive symptoms, physical activity, alcohol and cigarette use, and prescription medication use.
Evidence-Based Strategies for Better Sleep
Although this observational study cannot prove causation, it is among the most comprehensive multi-decade investigations into how recreational cannabis relates to adult sleep. The findings challenge the common belief that cannabis reliably improves sleep and underscore a need for caution in using cannabinoids as sleep aids.
“Our data do not support the belief that cannabis is helpful as a sleep aid,” said senior author Mercedes R. Carnethon, PhD, chair of the Department of Preventive Medicine at Feinberg. “As cannabis becomes more available and socially accepted, understanding its long-term associations with health behaviors such as sleep is increasingly important.”
Sleep medicine specialists recommend established behavioral strategies for people struggling with insomnia or restless nights rather than relying on cannabinoid-induced sedation. Advice includes maintaining a consistent sleep schedule, keeping the bedroom cool, dark, and quiet, avoiding electronic screens before bed, and adopting a calming pre-sleep routine such as reading, meditation, or a warm shower. If sleep problems persist or there are signs of sleep-disordered breathing (like loud snoring), consulting a healthcare provider is advised to evaluate underlying conditions.
Future research will seek to clarify how specific cannabinoid formulations, doses, and routes of administration (for example, vaporized concentrates versus oral edibles) influence sleep architecture and whether these effects differ by age or clinical context.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by staff.
About this Sleep Research:
- Media Contact: Kristin Samuelson
- Source: Northwestern University
- Image Credit: Image credited to Neuroscience News
- Original Research (Open Access): JAMA Network Open (Oct 1, 2026). Title: “Recent and Cumulative Cannabis Use and Sleep in Middle-Aged Adults.” Authors: Thanh-Huyen T. Vu, MD, PhD; Kristen L. Knutson, PhD; Reto Auer, MD, MAS; Julian Jakob, MD, PhD; Donald M. Lloyd-Jones, MD, MSc; and Mercedes R. Carnethon, PhD.
- DOI: 10.1001/jamanetworkopen.2026.38303
Abstract
Recent and Cumulative Cannabis Use and Sleep in Middle-Aged Adults
Importance
Cannabis is widely used and often promoted as a sleep aid, but high-quality evidence about its long-term effects on sleep is limited.
Objective
To evaluate associations between cumulative cannabis exposure from young adulthood to midlife, recent cannabis use, and both objective and subjective sleep outcomes in middle age.
Design, Setting, and Participants
This cohort study used data from the CARDIA study with 35 years of follow-up through the year-35 examination (2020–2022) and the CARDIA Year-35 Sleep Ancillary Study. Analyses were conducted from January to July 2026.
Exposures
Cumulative cannabis use was measured in cannabis-years (one cannabis-year = 365 days of use). Recent use was categorized as past 30-day use versus former or never use.
Main Outcomes and Measures
Objective sleep was measured with 7-day wrist actigraphy and subjective sleep with the Pittsburgh Sleep Quality Index (PSQI). Primary outcomes included objective sleep duration (short <6 hours, optimal 6–8 hours, long >8 hours), sleep percentage (low <85%), sleep fragmentation (highest quartile = high fragmentation), and wakefulness after sleep onset (WASO >=30 minutes), plus PSQI scores for subjective sleep quality (PSQI >5 = poor sleep).
Results
Among 1,266 participants (891 with objective and 1,128 with subjective sleep data), the mean age at year-35 was 60.7 years. After adjusting for multiple factors, each additional cannabis-year was associated with greater odds of low sleep percentage, high sleep fragmentation, and prolonged WASO. Recent use was linked to higher odds of low sleep percentage, high fragmentation, prolonged WASO, and long sleep duration compared with former or never users. No association was observed between cannabis use and self-reported sleep quality.
Conclusions and Relevance
Both cumulative and recent cannabis use were associated with poorer objectively measured sleep quality in midlife, while subjective sleep reports did not reflect these differences. These results highlight the importance of assessing both objective and subjective sleep and suggest potential adverse associations between long-term recreational cannabis exposure and midlife sleep health.