Cannabis use associated with increased suicide risk, even controlling for depression

Cannabis use has become increasingly normalized and legalized across the globe, but its impact on mental health is still being understood. A recent systematic review and meta-analysis published in Drug and Alcohol Dependence delves into the complex relationship between cannabis use, depression, and suicidal behavior. Cannabis use has been found to be a risk factor for depression, and consistent cannabis use has been associated with suicidality, suicidal behaviors, and actions, though the findings have been mixed.

This study reviewed over 1,000 articles on major databases and included 25 articles in the systematic review. The review assessed all the studies, paying close attention to how depression was measured and its role (confounder, moderator, or mediator).

Key findings showed that cannabis use is associated with an increased risk of suicidal ideation and attempts, even when controlling for depression. Among adolescents, cannabis use was linked to a 1.85 times higher likelihood of attempting suicide, whereas for adults, the risk of suicidal thoughts was almost doubled. These findings suggest that while depression may partially confound the association, cannabis use is independently linked to increased suicidality. However, it is important to note that nearly half of the studies included found no significant relationship after adjusting for depression, highlighting the mixed and nuanced nature of the evidence.

While the evidence on whether depression moderates this relationship was inconclusive, the authors point to the possibility that cannabis use may be more harmful to individuals already struggling with depression and may elevate risk among individuals without depression. In addition, they note that cannabis may act as a catalyst, accelerating or amplifying depressive processes. The authors recommend prioritizing longitudinal research that considers the temporal sequence of cannabis use, depression onset, and suicidal behavior, as well as the role of comorbid mental health and substance use disorders.

Key Takeaways

• Cannabis use remains significantly associated with suicidal ideation and suicide attempts among both adolescents and adults, even after adjusting for depression.

  
  

• Depression may contribute to the relationship between cannabis use and suicidality, but does not fully explain it, suggesting that cannabis use poses an independent risk for suicidal thoughts and behaviors.

  
  

• More research is still needed to understand the relationship between depression and cannabis use and suicidality.

This review, published in Drug and Alcohol Dependence, was conducted by researchers Gustave Maffre Maviel, Camille Davisse-Paturet, and Maria Melchior from the Pierre Louis Institute of Epidemiology and Public Health (Sorbonne University, INSERM, France), Guillaume Airagnes from INSERM (France), and Camilla Somma from the University of Verona (Italy).

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Reference:

Maviel, G. M., Somma, C., Davisse-Paturet, C., Airagnes, G., & Melchior, M. (2025). The role of depression in the relationship between cannabis use and suicidal behaviours: A systematic review and meta-analysis. Drug and Alcohol Dependence, 273, 112714. https://doi.org/10.1016/j.drugalcdep.2025.112714