Combat Exposure and Risk of Suicide Attempt Among Danish Army Military Personnel

Objective: The aim of this study was to estimate the association between self-reported perceived danger during deployment, measured as combat exposure or witnessing the consequences of war, and post-deployment suicide attempts among military personnel. Furthermore, the effect of post-deployment symptoms of post-traumatic stress disorder (PTSD) and/or depression on the risk of suicide attempts was also evaluated. Methods: This observational cohort study included Danish Army military personnel who returned from deployment in international missions from 1998 to 2016 and had completed a post-deployment questionnaire. Perceived exposure to danger was ascertained by self-report. Data on suicide attempt were retrieved from national registers. Adjusted Cox regression analyses were used to evaluate if military personnel indicating high level of combat exposure were more likely to have attempted suicides post-deployment than military personnel with lower levels of combat exposure. Results: Eighty-three suicide attempts were registered after homecoming among 12,218 military personnel. Perceived higher exposure to combat was associated with the risk of suicide attempt (hazard ratio = 1.08; 95% CI, 1.01-1.16). Furthermore, the association between combat exposure and suicide attempt was fully mediated by post-deployment symptoms of PTSD and/or depression. No association was found between witnessing consequences of war and the risk of post-deployment suicide attempt. Conclusions: This nationwide study found that combat exposure was associated with an increased risk of suicide attempt among military personnel. This association was, however, fully mediated by mental disorders (PTSD and/or depression). These findings suggest that better psychological follow-up of military personnel identified as having PTSD and/or depression may be warranted.