CORVALLIS, Ore. — Frequent cannabis users had higher cortisol levels upon waking than non-users in a small Oregon State University study. Researchers said the findings do not establish whether cannabis use caused the difference, but suggested the results deserve further investigation.
The study, published in the journal Cannabis, examined cannabis use in relation to the hypothalamic-pituitary-adrenal axis, the body’s primary stress-response system. Researchers Julia Donner, Alexia Obrochta, and Anita Cservenka of OSU’s College of Liberal Arts conducted the study.
Cortisol, a hormone produced by the adrenal glands, helps regulate blood pressure, blood sugar, metabolism, inflammation, and the body’s response to stress. Levels normally fluctuate throughout the day and rise around waking, but persistently elevated cortisol has been associated with several physical and mental health conditions.
The researchers recruited 82 participants: 39 who had used cannabis at least three days per week during the preceding year and 43 controls. Participants collected saliva samples upon waking, 30 minutes later, and in the evening on two consecutive weekdays.
The cortisol awakening response—the change between the initial waking measurement and the sample collected 30 minutes later—did not differ significantly between the groups. Frequent cannabis users, however, had higher cortisol levels in the initial waking samples. The higher levels within that group also were associated with more self-reported cannabis-related consequences, such as reduced motivation, impaired work or school performance, and risky behavior.
“Our research suggests cortisol levels upon awakening may serve as a neurobiological marker of problematic cannabis use, and that connection needs to be investigated further,” Cservenka said.
Because the study was cross-sectional, it could not determine whether frequent cannabis use contributed to higher waking cortisol, whether stress-related differences influenced cannabis use, or whether other factors accounted for the association.
The findings come as cannabis use among young adults has increased. According to the latest Monitoring the Future panel report, 29 percent of U.S. adults ages 19–30 reported past-month use in 2024, up from 18.5 percent in 2014. Use on 20 or more occasions during the preceding month rose from 7.1 percent to 10.8 percent during the same period.
Cservenka said larger longitudinal studies are needed to clarify the relationship between frequent cannabis use and cortisol.
The study was funded by Oregon State University, the OSU Center for the Humanities, and the OSU College of Liberal Arts.
