Cannabis use doubled the odds of suicide attempts among 86,000 adolescents across 21 countries | Research

The takeaway

In a study of 86,254 adolescents from 21 low- and middle-income countries, both past-month and lifetime cannabis use were independently associated with approximately doubled odds of suicide attempts, even after adjusting for confounders.

Global health researchers, suicide prevention specialists, and policymakers in countries considering cannabis legalization.

2x suicide attempt risk

What the researchers found

Past 30-day cannabis use was significantly associated with suicide attempts (OR 2.03, 95% CI 1.42-2.91) after multivariable adjustment. Lifetime cannabis use showed an even stronger association (OR 2.30, 95% CI 1.74-3.04). These associations held across 21 countries with widely varying cannabis prevalence rates.

Why it matters

This is one of the largest studies examining the cannabis-suicide association, and the first to systematically assess it across multiple low- and middle-income countries. The consistency of the finding across vastly different cultural contexts strengthens the case for a real association.

The numbers in context

86,254 adolescents from 21 countries. Mean age 13.7. Past 30-day cannabis: 2.8% (range 0.5% Laos to 37.6% Samoa). Lifetime cannabis: 3.9%. Suicide attempts past year: 10.5%. Adjusted OR: 2.03 (30-day) and 2.30 (lifetime).

How the study worked

Cross-sectional analysis of the Global School-based Student Health Survey data from 86,254 adolescents (mean age 13.7) in 21 low- and middle-income countries. Multivariable logistic regression adjusted for potential confounders.

What this study cannot tell us

Cross-sectional design cannot establish causation. Self-reported measures in school settings. Students not in school were excluded. Cultural differences in reporting both cannabis use and suicidality may affect comparisons. Specific confounders like mental health treatment availability could not be assessed.

How to read the evidence

Rated strong because this is a very large multi-country study using standardized methodology, though the cross-sectional design limits causal inference.

When this study was published

Published in 2019 using Global School-based Student Health Survey data.

The bigger picture

The cannabis-suicide link has been primarily studied in high-income countries. This study shows the association extends to low- and middle-income countries with very different cannabis use patterns, healthcare systems, and cultural contexts, suggesting a robust relationship.

Questions still open

Is the relationship causal or confounded by shared risk factors? Would prospective studies confirm these cross-sectional findings? Does the association vary by cannabis potency or type of use?

Common questions

Is cannabis use linked to suicide in teens?

In 86,254 adolescents across 21 countries, cannabis use was associated with roughly double the odds of suicide attempts, even after adjusting for other risk factors.

Does this apply to all countries?

The association was consistent across 21 low- and middle-income countries with cannabis prevalence ranging from 0.5% to 37.6%, suggesting it is not specific to any one cultural context.

Read the original research

Cannabis use and suicide attempts among 86,254 adolescents aged 12-15 years from 21 low- and middle-income countries.

European psychiatry : the journal of the Association of European Psychiatrists, 56, 8-13

View on PubMed ↗Publisher’s paper ↗

Citation

Carvalho, Andre F; Stubbs, Brendon; Vancampfort, Davy; Kloiber, Stefan; Maes, Michael; Firth, Joseph; Kurdyak, Paul A; Stein, Dan J; Rehm, Jürgen; Koyanagi, Ai. (2019). Cannabis use and suicide attempts among 86,254 adolescents aged 12-15 years from 21 low- and middle-income countries.. European psychiatry : the journal of the Association of European Psychiatrists, 56, 8-13. https://doi.org/10.1016/j.eurpsy.2018.10.006