Past-Year Co-Use of Alcohol and Opioid and Suicidal Behaviors in U.S. Adults with Prior Military Service

Alcohol use and opioid use independently increase the risk of suicidal behaviors. These substances are also frequently used concurrently, yet the extent to which their co-use contributes to suicidal behaviors at the population level remains insufficiently understood. This gap is particularly relevant among adults with prior military service, who experience elevated burdens of chronic pain, opioid exposure, and mental health comorbidities. We therefore examined whether past-year alcohol-opioid co-use was associated with suicidal behaviors among U.S. adults and assessed whether these associations differed by military service status and across pre- and post-COVID-19 periods.

We conducted a repeated cross-sectional analysis of adults aged ≥18 years using 2014-2023 data from the National Survey on Drug Use and Health (n = 544,488; 19,047 with prior military service). Past-year suicidal behaviors were defined as ideation, planning, or attempt. Substance use groups were categorized as alcohol-only, opioid-only, alcohol-opioid co-use, or neither. Year-specific multivariable logistic regression models adjusted for sociodemographic and clinical covariates were pooled using random-effects meta-analysis. Analyses were stratified by pandemic period (2014-2019 vs. 2020-2023). Interaction terms and marginal effects assessed effect modification by military service.

Among adults without prior military service, alcohol-opioid co-use (adjusted OR = 1.61, 95% CI, 1.37-1.90) and opioid-only use (aOR = 1.59, 95% CI, 1.27-2.00) were associated with suicidal behaviors after full adjustment. Among adults with prior military service, co-use was significant in minimally adjusted models but attenuated after full adjustment. Stratified analyses indicated stronger associations for co-use during the COVID-19 period, particularly among those with prior military service. Interaction analyses showed limited evidence of effect modification by military status after adjustment.

Alcohol-opioid co-use is associated with increased odds of suicidal behaviors in U.S. adults, with variation across military service status and pandemic periods. These findings highlight the importance of considering polysubstance use and contextual stressors in understanding suicide risk.