Heavy Cannabis Use Combined With Disrupted Cortisol Patterns Tripled the Risk of Suicidal Thoughts | Research

The takeaway

In a 5-year study of 368 male cannabis users, those with heavy THC use and a blunted cortisol stress response had more than three times the odds of suicidal thoughts and behaviors compared to controls.

Mental health clinicians working with cannabis users, suicide prevention researchers, and neuroendocrinology researchers.

3.2x higher odds of suicidal thoughts in heavy users with blunted cortisol response

What the researchers found

Cannabis users with a blunted cortisol awakening response (CAR), flattened diurnal cortisol slope (DCS), and higher cortisol area under the curve who reported heavy cannabis use had 3.2 times higher odds of suicidal thoughts and behaviors (OR 3.2, 95% CI: 2.4-4.1) compared to controls.

Why it matters

This study proposes a biological mechanism linking cannabis use to suicide risk: THC may dysregulate the body's stress response system (HPA axis), and this dysregulation is what drives suicidal ideation. This reframes the cannabis-suicide link from a purely behavioral to a neurobiological phenomenon.

The numbers in context

368 male cannabis users; 5-year follow-up; OR 3.2 (95% CI: 2.4-4.1) for STB in heavy users with blunted cortisol; four THC dosage categories analyzed; saliva cortisol via LC-MS/MS

How the study worked

Population-based matched-pair nested case-control study within a three-wave longitudinal cohort (2019-2024) of 368 male continued cannabis users. Participants were categorized by THC dosage (low, moderate, high, relapse). Cortisol was measured via saliva LC-MS/MS and urinary metabolites via GC-MS. Structural equation modeling examined relationships.

What this study cannot tell us

Male participants only. Cannot fully establish causality despite longitudinal design. Cortisol patterns can be affected by many factors beyond cannabis. The specific cohort (congress 60 clients) may not generalize.

How to read the evidence

Prospective cohort with biological measurements and appropriate modeling, but male-only sample and specific cohort limit generalizability.

When this study was published

Published in 2024 with data from 2019-2024.

The bigger picture

The HPA axis dysregulation model could explain why some cannabis users develop suicidal ideation while others do not: the combination of heavy use and cortisol disruption may identify a high-risk subgroup.

Questions still open

Would cortisol monitoring identify cannabis users at highest suicide risk?
Does cannabis cessation restore normal cortisol patterns and reduce suicide risk?

Common questions

Does cannabis cause suicidal thoughts?

This study found that heavy cannabis use combined with a disrupted stress hormone pattern tripled the odds of suicidal thoughts, suggesting a biological mechanism linking the two.

Are all cannabis users at risk?

No. The elevated risk was specific to heavy users who also showed disrupted cortisol patterns. Light or moderate users without cortisol disruption were not at the same elevated risk.

Read the original research

Prediction of suicidal thoughts and behaviors based on the diurnal cortisol pattern and THC dosage in continued cannabis users, a 5 year population-based matched cohort study.

Psychiatry research, 339, 116091

View on PubMed ↗Publisher’s paper ↗

Citation

Pirnia, Bijan; Soleimani, Ali; Farhoudian, Ali; Zahiroddin, Alireza. (2024). Prediction of suicidal thoughts and behaviors based on the diurnal cortisol pattern and THC dosage in continued cannabis users, a 5 year population-based matched cohort study.. Psychiatry research, 339, 116091. https://doi.org/10.1016/j.psychres.2024.116091