The role of depression in the relationship between cannabis use and suicidal behaviours

Drug and Alcohol Dependence

Drug and Alcohol Dependence – Volume 273, 1 August 2025, 112714

by Gustave Maffre Maviel,  Camilla Somma, Camille Davisse-Paturet, Guillaume Airagnes,  Maria Melchior.

A systematic review and meta-analysis

Highlights
  • Studies reveal a significant association between cannabis use and suicidality, independent of depression.
  • Existing research is inconsistent regarding whether the association differs between individuals with and without depression.
  • More research is needed to identify the pathways linking cannabis use to suicidality.

Abstract

Background

Depression has been cited as a possible confounder, moderator, and mediator of the relationship between cannabis use and suicidal behaviours. We aimed to assess the role of depression in the relationship between cannabis use and suicidal behaviours by systematically reviewing existing literature in the general population.

Methods

We systematically searched PubMed, Science Direct and Psych Articles from database inception to May 20th 2024, for quantitative observational studies investigating the role of depression in the association between cannabis use and suicidal behaviours. We conducted a meta-analysis to examine the confounding role of depression and search for qualitative arguments in favour of moderating and/or mediating roles of depression.

Results

We screened 1081 articles, selected 43 for full-text screening and finally included 25. Among adolescents, cannabis use was associated with suicidal ideation (OR = 1.46 [1.17, 1.83]) and suicide attempts (OR = 2.17 [1.56, 3.03]) in studies adjusting for depression. Among adults, cannabis use was associated with suicidal ideation (OR = 1.78 [1.28, 2.46]) in studies adjusting for depression. 12 out of 25 studies found no association between cannabis use and suicidality after adjustment for depression. Six studies investigated a potential moderating role of depression, with four reporting significant but conflicting results. No article investigated the mediating role of depression.

Discussion

There is a clear relationship between cannabis use and suicidal behaviours, which is partly confounded by depression. Studies investigating a moderating role of depression did not agree about the direction of moderation. Further research using methodologies that consider the chronology of events is needed. 

Keywords

Cannabis
Cannabis use
Cannabis use disorder
Suicidal behaviours
Suicide
Depression
Source:  https://www.sciencedirect.com/science/article/pii/S037687162500167X?
Elsevier Science has two locations: one in New York, United States, and the other in Amsterdam, Netherlands.  

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