Meta-Analysis Found Cannabis Use Linked to Increased Suicide Risk, Especially With Heavy Use
A meta-analysis found that any cannabis use was associated with a 2.6x increased risk of suicide death, 1.4x risk of suicidal ideation, and 2.2x risk of suicide attempt, with heavy use roughly doubling these associations.
Quick Facts
What This Study Found
This review and meta-analysis examined the relationship between cannabis use and suicidality across three outcomes: suicide death, suicidal ideation, and suicide attempt.
For chronic cannabis use, the pooled odds ratios from meta-analyses were: suicide death (2.56, based on 4 studies), suicidal ideation with any use (1.43, from 6 studies) and heavy use (2.53, from 5 studies), and suicide attempt with any use (2.23, from 6 studies) and heavy use (3.20, from 6 studies).
For acute cannabis use, the evidence was mostly limited to toxicology reports finding cannabis in approximately 9.5% of suicide decedents, with higher detection rates among those who died by non-overdose methods. The authors concluded that chronic cannabis use can predict suicidality, but noted inconsistent measurement of cannabis exposure and sometimes inadequate control for known risk factors.
Key Numbers
Suicide death: OR 2.56 (4 studies). Suicidal ideation (any use): OR 1.43 (6 studies). Suicidal ideation (heavy use): OR 2.53 (5 studies). Suicide attempt (any use): OR 2.23 (6 studies). Suicide attempt (heavy use): OR 3.20 (6 studies). Acute cannabis detection in suicides: 9.5%.
How They Did This
Systematic search of Medline, PsychInfo, Google Scholar, and public databases for the period 1990-2015. Random effects meta-analyses were conducted separately for any cannabis use versus heavy cannabis use and for each suicidality outcome.
Why This Research Matters
These findings quantify the association between cannabis use and suicide risk across multiple outcomes. The dose-response pattern (heavier use associated with greater risk) adds plausibility to the association, though the authors cautioned about confounding.
The Bigger Picture
The cannabis-suicide association is one of the more concerning findings in cannabis epidemiology. While this meta-analysis cannot prove causation, the consistency across outcomes and the dose-response relationship are notable and have implications for clinical screening and risk assessment.
What This Study Doesn't Tell Us
The authors acknowledged lack of homogeneity in how cannabis exposure was measured across studies, and in some cases insufficient control for known suicide risk factors (depression, other substance use, childhood adversity). The number of studies for some outcomes was small (4 for suicide death). Observational data cannot prove cannabis causes suicidality.
Questions This Raises
- ?Does cannabis use directly increase suicide risk, or is it a marker for other risk factors?
- ?Would adequate control for all known confounders eliminate the association?
Trust & Context
- Key Stat:
- Heavy cannabis use associated with 3.2x increased risk of suicide attempt
- Evidence Grade:
- This is a systematic review with meta-analysis pooling data across multiple studies, providing strong evidence for the association, though the quality of included studies varied.
- Study Age:
- Published in 2016, covering literature from 1990-2015. Additional studies on this topic have been published since then.
- Original Title:
- A literature review and meta-analyses of cannabis use and suicidality.
- Published In:
- Journal of affective disorders, 195, 63-74 (2016)
- Authors:
- Borges, Guilherme(2), Bagge, Courtney L, Orozco, Ricardo(2)
- Database ID:
- RTHC-01111
Evidence Hierarchy
Combines results from multiple studies to find an overall pattern.
What do these levels mean? →Frequently Asked Questions
Does cannabis use cause suicidal thoughts?
The meta-analysis found a consistent association between cannabis use and suicidality across multiple outcomes, but cannot prove causation. Some of the association may be explained by shared risk factors such as depression, childhood adversity, or other substance use. However, the dose-response pattern (heavier use, higher risk) adds some weight to the possibility of a causal contribution.
Should people with suicidal thoughts avoid cannabis?
The evidence suggests that cannabis use, particularly heavy use, is associated with increased suicide risk. People experiencing suicidal thoughts should seek professional support. If you or someone you know is in crisis, contact the 988 Suicide and Crisis Lifeline by calling or texting 988.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-01111APA
Borges, Guilherme; Bagge, Courtney L; Orozco, Ricardo. (2016). A literature review and meta-analyses of cannabis use and suicidality.. Journal of affective disorders, 195, 63-74. https://doi.org/10.1016/j.jad.2016.02.007
MLA
Borges, Guilherme, et al. "A literature review and meta-analyses of cannabis use and suicidality.." Journal of affective disorders, 2016. https://doi.org/10.1016/j.jad.2016.02.007
RethinkTHC
RethinkTHC Research Database. "A literature review and meta-analyses of cannabis use and su..." RTHC-01111. Retrieved from https://rethinkthc.com/research/borges-2016-a-literature-review-and
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.