Moral injury and substance use disorders among US combat veterans: results from the 2019-2020 National Health and Resilience in Veterans Study

Background Exposure to potentially morally injurious events (PMIEs) is associated with increased risk for substance use disorders (SUDs), although population-based studies remain limited. The goal of this study was to better understand the relationships between PMIE exposure and lifetime and past-year alcohol use disorder (AUD), drug use disorder (DUD), and SUD. Methods Data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study, which surveyed a nationally representative sample of 1321 combat veterans. Multivariable analyses examined associations between three types of PMIE exposure (perpetration, witnessing, and betrayal), and lifetime and past-year AUD, DUD, and SUD, adjusting for sociodemographic variables, combat exposure severity, prior trauma, and lifetime posttraumatic stress disorder and major depressive disorder. Results Perpetration was associated with increased odds of lifetime AUD (OR 1.15; 95% CI 1.01-1.31) and lifetime SUD (OR 1.18; 95% CI 1.03-1.35). Witnessing was associated with greater odds of past-year DUD (OR 1.20; 95% CI 1.04-1.38) and past-year SUD (OR 1.14; 95% CI 1.02-1.28). Betrayal was associated with past-year AUD (OR 1.20; 95% CI 1.03-1.39). A large proportion of the variance in past-year AUD was accounted for by betrayal (38.7%), while witnessing accounted for 25.8% of the variance in past-year DUD. Conclusions Exposure to PMIEs may be a stronger contributor to SUDs among veterans than previously known. These findings highlight the importance of targeted assessment and treatment of moral injury among veterans with SUDs, as well as attending to specific types of morally injurious experiences when conceptualizing and planning care.