Abstract
INTRODUCTION: Little is known if cannabis and tobacco use are indicators of suicide-related risks. This longitudinal study examined associations between cannabis and tobacco use with risks of suicide attempt/death and overdose death over a 2-year follow-up in a cohort of Veterans prescribed opioids. METHODS: This study analyzed data in 2024 using a national cohort of 923,291 Veterans receiving opioid analgesics in Veterans Health Administration clinics collected during 2014-2019. Cannabis and tobacco use were assessed at cohort entry. Outcomes (suicide attempts, suicide death, overdose death) were obtained at follow-up through 2021. Cause-specific hazard models were used to examine associations between cannabis and tobacco use with each outcome, adjusting for well-established risk factors for suicide/overdose (e.g., substance use disorders, mental health, socio-demographics). RESULTS: At baseline, 5.4% of the cohort used cannabis, and 39.4% used tobacco. At the end of follow-up (median follow-up time was 6.7-6.8 years), 2.2% of the sample had attempted suicide, 0.4% had died by suicide, and 0.5% had died by overdose. In adjusted models, cannabis use was associated with a higher rate of suicide attempt (hazard ratio [HR] 1.11, 95%CI: 1.06-1.15). Current use of tobacco at baseline (versus never use) was associated with a higher rate of suicide attempts (HR 1.18, 95%CI: 1.13-1.22), suicide deaths (HR 1.19, 95%CI: 1.07-1.32), and overdose deaths (HR 1.67, 95%CI: 1.51-1.83). CONCLUSIONS: Cannabis and tobacco use were associated with suicide attempts/deaths and overdose deaths among Veterans prescribed opioid analgesics, underscoring a need for monitoring patients who use tobacco and cannabis in this population.