Both cannabis and tobacco use were associated with higher suicide attempt rates among veterans prescribed opioids

Among over 900,000 veterans on opioids, cannabis use was associated with 11% higher suicide attempt rates, and tobacco with higher rates of attempts, suicide deaths, and overdose deaths.

Nguyen, Nhung et al.·American journal of preventive medicine·2026·Strong EvidenceLongitudinal Cohort
RTHC-08518Longitudinal CohortStrong Evidence2026RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Longitudinal Cohort
Evidence
Strong Evidence
Sample
N=923,291

What This Study Found

Cannabis use: HR 1.11 for suicide attempts. Tobacco: HR 1.18 for attempts, HR 1.19 for suicide deaths, HR 1.67 for overdose deaths. Associations persisted after adjusting for substance use disorders, mental health, and sociodemographics.

Key Numbers

923,291 veterans. 5.4% cannabis, 39.4% tobacco. Median follow-up 6.7-6.8 years. Cannabis: HR 1.11 suicide attempt. Tobacco: HR 1.18 attempt, HR 1.19 suicide death, HR 1.67 overdose death.

How They Did This

Longitudinal cohort of 923,291 veterans receiving opioid analgesics in VHA clinics (2014-2019) with follow-up through 2021. Cause-specific hazard models adjusted for established suicide/overdose risk factors.

Why This Research Matters

Veterans on opioids are already at elevated risk. Identifying cannabis and tobacco as additional risk markers could inform screening and monitoring protocols.

The Bigger Picture

Identifying modifiable or monitorable risk markers could strengthen safety protocols without restricting necessary pain management.

What This Study Doesn't Tell Us

Observational. Cannabis/tobacco assessed at baseline only. Cannabis associated with attempts, not deaths. Residual confounding possible.

Questions This Raises

  • ?Is cannabis use causal or a marker for other risk factors?
  • ?Would addressing tobacco in opioid-prescribed veterans reduce overdose deaths?

Trust & Context

Key Stat:
HR 1.67 for overdose death among tobacco-using veterans on opioids
Evidence Grade:
Very large national cohort with long follow-up and extensive adjustment, but observational design limits causal claims.
Study Age:
2026 publication using 2014-2021 VA data
Original Title:
Associations of Cannabis and Tobacco Use with Suicide Attempt, Suicide Death, and Overdose Death Among Veterans Prescribed Opioid Analgesics.
Published In:
American journal of preventive medicine, 108309 (2026)
Database ID:
RTHC-08518

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Follows a group of people over time to track how outcomes develop.

What do these levels mean? →

Frequently Asked Questions

Does cannabis cause suicide?

The study found an 11% higher rate of suicide attempts associated with cannabis use after adjusting for mental health conditions, but cannot prove causation.

Why was tobacco more strongly linked to overdose death?

Tobacco was linked to 67% higher overdose death rates. This may reflect shared neurobiological pathways or tobacco as a marker for greater overall substance use severity.

Read More on RethinkTHC

Cite This Study

RTHC-08518·https://rethinkthc.com/research/RTHC-08518

APA

Nguyen, Nhung; Leonard, Samuel; Byers, Amy L; Austin, Peter C; Krebs, Erin E; Sandbrink, Friedhelm; Bravata, Dawn M; Keyhani, Salomeh. (2026). Associations of Cannabis and Tobacco Use with Suicide Attempt, Suicide Death, and Overdose Death Among Veterans Prescribed Opioid Analgesics.. American journal of preventive medicine, 108309. https://doi.org/10.1016/j.amepre.2026.108309

MLA

Nguyen, Nhung, et al. "Associations of Cannabis and Tobacco Use with Suicide Attempt, Suicide Death, and Overdose Death Among Veterans Prescribed Opioid Analgesics.." American journal of preventive medicine, 2026. https://doi.org/10.1016/j.amepre.2026.108309

RethinkTHC

RethinkTHC Research Database. "Associations of Cannabis and Tobacco Use with Suicide Attemp..." RTHC-08518. Retrieved from https://rethinkthc.com/research/nguyen-2026-associations-of-cannabis-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.