Cannabis use before age 15 was linked to nearly 4x higher risk of suicidal thoughts and 5x higher risk of suicide attempts in young Mexicans | Research

The takeaway

In a follow-up study of over 1,000 young Mexicans, early cannabis use (before age 15), heavy use, and cannabis use disorders all significantly predicted later suicidal thoughts and attempts.

Read this if you want to understand the link between early cannabis use and suicide risk in young people.

Cannabis use before age 15: 4x suicidal ideation risk, 5x suicide attempt risk

What the researchers found

In a prospective study following 1,071 young Mexicans from 2005 to 2013, cannabis use before age 15 was associated with nearly 4 times the risk of suicidal ideation (RR=3.97) and over 5 times the risk of suicide attempt (RR=5.23).

Early-onset cannabis use disorder among cannabis users tripled the risk of ideation (RR=3.30) and quadrupled the risk of attempt (RR=4.14). High-frequency cannabis use was associated with 4.6 times the risk of attempt, and recent cannabis use disorder with 4.7 times the risk.

Other drugs showed some similar associations but generally to a lesser degree. For alcohol, only initiation before age 15 was linked to increased attempt risk (RR=1.79).

Why it matters

Suicide is a leading cause of death among young people in Mexico and globally. This prospective design, following the same individuals over eight years, strengthens the evidence that early and heavy cannabis use precedes suicidal behavior rather than simply co-occurring with it. The specificity of cannabis effects beyond other substances is notable.

The numbers in context

Cannabis before age 15: ideation RR=3.97 (95% CI 1.43-11.03), attempt RR=5.23 (95% CI 1.17-23.32). Early-onset DUD: ideation RR=3.30, attempt RR=4.14. High-frequency use: attempt RR=4.60. Recent DUD: attempt RR=4.74. Alcohol before age 15: attempt RR=1.79.

How the study worked

Prospective follow-up of the original Mexican Adolescent Mental Health Survey conducted in 2005, with follow-up in 2013 (n=1,071). Researchers estimated risk ratios for incident suicidal ideation and attempt based on earlier substance use patterns, adjusting for confounders.

What this study cannot tell us

Relatively small follow-up sample (1,071 participants). Wide confidence intervals on some estimates reflect limited statistical power. Observational design cannot confirm causation. Self-reported substance use and suicidal behavior may be subject to reporting bias. The study cannot fully account for shared risk factors.

How to read the evidence

Prospective cohort study with 8-year follow-up. Strong temporal design but limited by small sample size and wide confidence intervals.

When this study was published

Published in 2017. The association between early cannabis use and suicidal behavior continues to be studied across different populations.

The bigger picture

The consistency of the cannabis-suicide association across early use, heavy use, and use disorders suggests a dose-response relationship. The Latin American context is important because cannabis policy and cultural attitudes differ from North America and Europe, yet the associations appear similar, suggesting biological rather than purely cultural pathways.

Questions still open

What mechanisms link early cannabis use to later suicidal behavior? Would prevention of early cannabis initiation reduce suicide rates among Mexican youth? Do these associations differ across Latin American countries with varying cannabis policies?

Common questions

Does cannabis cause suicidal thoughts?

This study found that early and heavy cannabis use preceded suicidal behavior in a prospective design, which is stronger evidence than cross-sectional studies. However, it cannot prove causation. The association could involve cannabis exacerbating underlying vulnerability, or shared risk factors not fully controlled for.

Why is age of first use important?

Starting cannabis before age 15 carried the highest risk ratios in this study. The adolescent brain is still developing, particularly in areas governing emotional regulation and impulse control. Early exposure may disrupt these developmental processes in ways that increase vulnerability to suicidal thinking.

Read the original research

Alcohol, cannabis and other drugs and subsequent suicide ideation and attempt among young Mexicans.

Journal of psychiatric research, 91, 74-82

View on PubMed ↗Publisher’s paper ↗

Citation

Borges, Guilherme; Benjet, Corina; Orozco, Ricardo; Medina-Mora, Maria-Elena; Menendez, David. (2017). Alcohol, cannabis and other drugs and subsequent suicide ideation and attempt among young Mexicans.. Journal of psychiatric research, 91, 74-82. https://doi.org/10.1016/j.jpsychires.2017.02.025