Implications of Psychiatric Comorbidity Among Combat Veterans

The objectives of this study were to determine the baseline prevalence of comorbid mental disorder diagnoses among combat-deployed United States Marine Corps personnel and to assess the relationships between baseline comorbid disorders and post-deployment psychological health and career outcomes. The current study examined medical, deployment, and career records for 136,300 U.S. Marines who enlisted between 2002 and 2005. Results. The overall prevalence of psychiatric comorbidity at baseline was 1.3, while the overall prevalence by the end of the study period was 3.5. The strongest predictors of receiving one or more psychiatric diagnoses following first combat deployment were comorbid and singular baseline disorders. Comorbid baseline mental health diagnoses also greatly increased the risk of attrition. Compared with participants with no postdeployment psychiatric diagnoses, participants with two or more postdeployment diagnoses were thirteen times more likely to attrite, and participants with one postdeployment diagnosis were five times more likely to attrite. Comorbid psychiatric diagnoses were consistently the strongest predictor of negative postdeployment psychiatric and career outcomes. This finding suggests that military personnel with a history of multiple mental health disorders who are deployed to a combat zone are at a greater risk for adverse psychiatric outcomes and early attrition from service than Marines with no or one disorder.