The body's stress system starts working before you do. Cortisol climbs in the half hour after your eyes open, priming you for whatever the day holds. The peer-reviewed paper behind a widely circulated Oregon State finding is now available, and it shows that people who used cannabis frequently began that climb from a higher floor.
The study appeared in the journal Cannabis, published by the Research Society on Marijuana. Julia Donner, Alexia Obrochta and Anita Cservenka compared saliva samples from 39 adults with frequent cannabis use against 43 healthy controls, collected at three points, immediately on waking, 30 minutes later and in the evening, across two consecutive weekdays.
The size of the morning rise was statistically indistinguishable between groups. The starting point was not.
The Rise Was Normal, the Starting Line Was Not
The measurement at the center of the study is the cortisol awakening response, or CAR. Subtract the waking cortisol value from the value 30 minutes later, and the difference is treated as a marker of how well the body gears up for the demands ahead.
Earlier work by other groups had reported a blunted CAR in frequent cannabis users. This study did not reproduce that. The between-group difference came out nonsignificant at p = 0.23.
What separated the groups was the baseline. At awakening, the cannabis group had significantly higher cortisol than controls, at p = 0.047. Subjective stress was positively related to waking cortisol across the whole sample, at p = 0.001.
The detail that gives the finding teeth is what the elevation correlated with. Higher awakening cortisol tracked with cannabis-related consequences, the negative outcomes people report from their own use, at p = 0.007. Cservenka, who led the work, said awakening cortisol may serve as "a neurobiological marker of problematic cannabis use" and that the connection needs further investigation.
She also framed the failure to replicate the blunted-CAR result as a signal of real nuance: "Earlier studies by other researchers found CAR to be blunted in frequent cannabis users, but we didn't replicate that finding, which suggests there is a lot of nuance that could be related to analytic strategies and sample characteristics."
Why the Number at 7 a.m. Matters
Cortisol is produced by the adrenal glands and governed by the hypothalamic-pituitary-adrenal axis, the neuroendocrine system that runs the body's response to stress. It is not simply a stress chemical. As the National Library of Medicine explains, cortisol affects almost every organ and tissue, helping control blood glucose, metabolism and blood pressure.
Short-term elevation is useful and normal. As the Oregon State announcement notes, prolonged periods of high cortisol are the problem, carrying associations with anxiety, depression and heart disease.
The researchers point out that this is one of relatively few studies to examine the HPA axis specifically in the context of frequent cannabis use, which matters given how many people that describes. They cite figures showing 29% of US adults aged 19 to 30 reporting cannabis use in the previous 30 days, nearly double the share 15 years earlier, with more than 10% of that age group using 20 or more times in a month. That trajectory is consistent with the Monitoring the Future panel survey, which the National Institute on Drug Abuse has repeatedly described as showing historically high cannabis use among adults in that age band.
The Loop Researchers Are Watching For
Stress is one of the most commonly cited reasons people use cannabis, and stress-motivated use is associated with problematic patterns. The researchers raise a specific concern that follows from that: cannabis may provide short-term relief while chronic use gradually degrades the system that handles stress in the first place.
If a dysregulated stress axis then makes daily life harder to tolerate, use could increase, and the cycle tightens.
That is a hypothesis, not a finding. The study measured cortisol and self-reported stress at a single window in time. It cannot show that cannabis pushed cortisol up, and it cannot rule out the reverse, that people whose stress systems already run hot are more likely to become frequent users. Disrupted sleep could independently drive both.
Eighty-Two People Cannot Settle the Direction
Several limits deserve weight. The sample was 82 people total, small for endocrine research. The design was cross-sectional. Saliva was collected on only two weekdays, and cortisol is notoriously sensitive to sleep timing, waking time, light exposure, caffeine, smoking, and stress on the day of collection. Subjective stress was self-reported. The paper does not characterize THC potency, product type or route of administration, all of which vary enormously in the current market.
None of this supports changing anything about medical treatment, and nobody should read a single cortisol measurement as a diagnostic test. Anyone concerned about their own cannabis use, or about persistent stress symptoms, is better served by a conversation with a qualified clinician than by a saliva kit.
Key Questions Answered
What did the study actually find?
Adults who used cannabis frequently had significantly higher cortisol at the moment of waking than nonusers, while the size of the normal 30-minute morning cortisol rise did not differ between groups.
Does this prove cannabis raises cortisol?
No. The design was cross-sectional and cannot establish direction. Causality remains undetermined.
What is the cortisol awakening response?
The rise in cortisol that everyone experiences after waking, peaking around 30 minutes later. It is calculated by subtracting the waking value from the 30-minute value and is used as an indicator of stress-system function.
Why did the elevated baseline stand out?
Because it correlated with self-reported negative consequences of cannabis use, which is what led the authors to propose awakening cortisol as a possible marker worth studying further.
Is high morning cortisol dangerous?
A single elevated reading means little. Sustained high cortisol over long periods has been associated with anxiety, depression, and cardiovascular disease, but this study did not measure health outcomes.
What would settle the question?
Longitudinal studies following the same individuals over time, with larger samples and better characterization of what and how much people are actually using.
