Depression as a Mediator between Combat Deployment and Substance Use among Veterans

Individuals who deploy to combat zones often develop increased rates of substance use problems, which may be due to self-medication for depressive symptoms. This study used logistic simple mediation analyses with bootstrapping to test whether depression mediates the relationship between combat zone experience and substance dependence or abuse (alcohol, nicotine, marijuana, opioids, other illicit drugs, and concurrent substance misuse) among military veterans via secondary data analysis of the 2013 to 2018 National Survey on Drug Use and Health (NSDUH; N = 14,121; 87.9% male; 54.4% age 50+; 75.2% white; 34.5% with combat zone experience). Analysis revealed that depression was only a significant mediator of the relationship between combat zone experience and alcohol dependence or abuse (OR = 1.020, 95% CI [1.002, 1.054], p < .05). Among the individual effects tested, the effect of combat zone experience on depression was only significant for alcohol (b = .167, 95% CI [.008, .326], p < .05), the effect of depression on substance dependence or abuse was significant for all substance categories except marijuana (ORs = 1.125 to 1.473, ps < .05), and the direct effect of combat zone experience on all substance dependence or abuse categories was not significant, ps > .05. Clinicians may consider screening for depression in all veterans, as well as screening for and emphasizing substance use prevention measures in those showing signs of depression. Our results also suggest the importance of combining treatments for depression and alcohol to improve treatment outcomes among veterans, regardless of combat zone experience.