Summary:
A 35-year study following adults from young adulthood into middle age reveals that both lifetime and recent cannabis use are tied to worse objectively measured sleep quality, characterized by lower sleep efficiency and higher fragmentation. Crucially, participants did not perceive their sleep to be impaired, revealing a disconnect between subjective sensation and physical sleep disruption.
Key Facts:
- Objective Disruption vs. Subjective Blind Spot: While wrist actigraphy demonstrated lower sleep efficiency, greater fragmentation, and prolonged awakenings, cannabis users did not report worse sleep on questionnaires compared to non-users.
- 35-Year Longitudinal Tracking: Evaluating 1,266 Black and white adults from the CARDIA study, the findings showed that cumulative lifetime exposure to cannabis correlates with degraded sleep architecture in middle age.
- Independent of Confounders: The link between cannabis use and poor sleep remained significant even after controlling for age, sex, race, alcohol, nicotine, physical activity, depression, and other substance use.
Source: Northwestern University
Millions of adults routinely turn to cannabis products, tinctures, and edibles as sleep aids, believing THC and cannabinoids induce faster and deeper rest. However, a landmark longitudinal study led by Northwestern Medicine suggests that cannabis may actually impair sleep quality over the long term—without users ever realizing it.
The findings, published in JAMA Network Open, reveal that both lifetime cumulative use and recent cannabis consumption are associated with significantly poorer objectively measured sleep quality in middle age. Yet, when asked about their own sleep, cannabis users generally reported no noticeable issues, uncovering an “illusion” of restorative sleep.
Tracking Sleep Quality Across Three and a Half Decades
To evaluate the long-term impact of cannabis on sleep patterns, investigators analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which has monitored a racially diverse cohort of Black and white American adults since 1985–1986.
Researchers tracked cannabis consumption repeatedly across nearly 35 years as participants transitioned from young adulthood into midlife. In middle age, 1,266 participants wore actigraphy sleep monitors on their wrists for seven consecutive days while simultaneously completing comprehensive subjective sleep questionnaires. This design allowed the researchers to directly compare physiological sleep data with participants’ subjective perceptions.
The wrist-worn monitors revealed that participants with greater cumulative lifetime exposure spent a lower proportion of their night actually asleep (reduced sleep efficiency), woke up more frequently throughout the night (higher sleep fragmentation), and experienced longer intervals of wakefulness after initial sleep onset.
Recent cannabis users displayed similar sleep disturbances and were also significantly more likely to sleep longer than eight hours per night, a pattern frequently linked to hypersomnia and non-restorative sleep cycles.
The Subjective Disconnect
Despite the physiological data showing fragmented, low-efficiency rest, participants who consumed cannabis did not rate their sleep quality any lower than non-users on clinical surveys.
“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. “The wearable device detected more nighttime disruption among participants with long-term cannabis exposure, but the participants themselves generally did not report worse sleep.”
This disconnect suggests that while cannabis may induce sedation or blunt conscious awareness of midnight awakenings, it disrupts the micro-architecture of restorative sleep beneath the surface.
Importantly, this relationship persisted even after researchers controlled for a battery of potential confounding variables, including age, biological sex, race, depressive symptoms, physical activity, alcohol consumption, cigarette smoking, and concurrent prescription medications.
Evidence-Based Strategies for Sleep Health
While the study was observational and not designed to establish direct causation, it represents one of the most robust multi-decade investigations into how recreational cannabis affects adult sleep.
“Our data do not support the belief that cannabis is helpful as a sleep aid,” emphasized senior author Mercedes R. Carnethon, PhD, chair of the Department of Preventive Medicine at Feinberg. “As cannabis becomes increasingly available and accepted, it’s important to better understand its long-term associations with health behaviors such as sleep.”
For those struggling with insomnia or restless nights, sleep medicine specialists recommend relying on evidence-based behavioral interventions rather than cannabinoid-induced sedation.
“Keep a regular bedtime, make your bedroom cool, dark and quiet, and avoid looking at phones and other screens right before bed,” advised co-author Kristen L. Knutson, PhD, associate professor of neurology and preventive medicine at Feinberg. “It can also help to establish a calming routine before sleep, such as reading, meditating or taking a shower. If sleep problems persist, or if you’re a loud snorer, talk with your healthcare provider to rule out an underlying sleep disorder.”
Future research will aim to parse the impact of specific cannabinoid formulations, dosages, and administration routes—such as vaporized concentrates versus oral edibles—on sleep architecture.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this Sleep Research:
- Media Contact: Kristin Samuelson
- Source: Northwestern University
- Image Credit: Image credited to Neuroscience News
- Original Research is Open Access: JAMA Network Open (Oct 1, 2026). “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 evidence of its long-term implications for sleep is limited.
Objective
To examine the associations of cumulative cannabis exposure from young adulthood to middle age and recent cannabis use with objective and subjective sleep outcomes in middle age.
Design, Setting, and Participants
This cohort study analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, including 35 years of follow-up through the year-35 examination (conducted in 2020 to 2022), and the CARDIA Year-35 Sleep Ancillary Study. Analyses were conducted from January 15 to July 15, 2026.
Exposures
Cumulative cannabis use (calculated in cannabis-years, with 1 cannabis-year equating to 365 days of use) and recent cannabis use (defined as past 30-day use vs former use and never use).
Main Outcomes and Measures
Objective sleep was assessed using data from 7-day wrist actigraphy, and subjective sleep was assessed with the Pittsburgh Sleep Quality Index (PSQI). Primary outcomes and measures were objective sleep duration (categorized as short [<6 hours], optimal [6-8 hours], or long [>8 hours]), sleep percentage (defined as percentage of time asleep; low percentage: <85%), sleep fragmentation (defined as the index of restlessness during sleep; high fragmentation: highest quartile), and wakefulness after sleep onset (WASO; prolonged WASO: ≥30 minutes) and subjective sleep quality (PSQI score and poor sleep quality: PSQI >5).
Results
A total of 1266 participants (891 with objective and 1128 with subjective sleep data) were analyzed. Among the 891 participants with objective sleep data, the mean (SD) age at the year-35 examination was 60.7 (3.6) years; the cohort included 564 females (63.3%) and 365 Black (41.0%) and 526 White (59.0%) participants. After multivariable adjustment, each additional cannabis-year was associated with higher odds of low sleep percentage (odds ratio [OR], 1.10; 95% CI, 1.06-1.14), high sleep fragmentation (OR, 1.04; 95% CI, 1.01-1.08), and prolonged WASO (OR, 1.21; 95% CI, 1.10-1.34). Compared with participants with former use and never use status, those with recent use had higher odds of low sleep percentage, high fragmentation, prolonged WASO, and long (vs optimal) sleep duration (eg, vs never use, prolonged WASO: OR, 3.23 [95% CI, 1.44-7.27]; long sleep duration: OR, 4.60 [95% CI, 1.81-11.70]). Cannabis use was not associated with subjective sleep quality.
Conclusions and Relevance
In this cohort study, both cumulative use and recent cannabis use were associated with poorer objective sleep quality, although no association with self-reported sleep quality was found. These findings underscore the importance of assessing both subjective and objective sleep and suggest potential adverse association between long-term recreational cannabis exposure and midlife sleep health.
