Study connects regular cannabis use with higher morning cortisol

Regular cannabis use is linked to higher morning cortisol levels, according to new research exploring the relationship between habitual consumption and stress. Scientists at Oregon State University investigated after previous studies hinted that the drug might elevate stress levels rather than reduce them. The team evaluated how frequent consumption impacts the hypothalamic-pituitary-adrenal axis, which serves as the primary stress responder in the human body by regulating cortisol release.

Cannabis reported that the study evaluated 39 frequent cannabis users alongside 43 control participants who used the substance rarely or not at all. Over two weekdays, participants collected saliva swabs immediately upon waking, 30 minutes later, and at 9:00 pm to measure cortisol concentrations. Volunteers also completed questionnaires assessing their perceived stress levels, sleep quality, and mental health symptoms.

Researchers focused on the cortisol awakening response, which represents the natural rise in cortisol levels peaking roughly 30 minutes after waking up to prepare the body for the day. While the rise in cortisol during that initial 30-minute window was similar between both groups, regular cannabis users exhibited higher baseline cortisol levels immediately upon waking. Behavioural neuroscientist Anita Cservenka noted that waking cortisol levels could serve as a neurobiological marker of problematic cannabis use requiring further investigation.

The findings provide a snapshot in time and cannot establish direct cause and effect, given the potential bi-directional relationship where stressed individuals may consume more cannabis. Excessive cortisol levels are associated with long-term health risks, including anxiety and heart disease. Cservenka emphasised that longitudinal studies tracking the same participant groups over extended periods will be necessary to clarify cause-and-effect dynamics.

The study comes amid rising global consumption, with US figures indicating that 29% of individuals aged 19 to 30 reported using cannabis in the past 30 days. Furthermore, over 10% of people in that age demographic reported using the drug 20 or more times within 30 days. Researchers noted that future studies must address discrepancies with earlier findings, which had previously observed a blunted cortisol awakening response among frequent users.