Suicide Among Regular-Duty Military Personnel: A Retrospective Case-Control Study of Occupation-Specific Risk Factors for Workplace Suicide

OBJECTIVE: The purpose of this study was to examine the epidemiology, phenomenology, and occupation-specific risk factors for suicide among regular-duty military personnel as a model for other professions at risk for workplace suicide. METHOD: Suicide incidence and methods were determined in a retrospective military cohort comprising all deaths (N=732) of regular-duty military personnel in the Irish Defence Forces between 1970 and 2002. A retrospective, case-control study using pair-matched military comparison subjects was conducted to determine occupation-specific risk factors for suicide, particularly by firearm, among military personnel. Risk factors were subjected to chi-square analysis or independent t tests and entered into a binary logistic regression analysis model. RESULTS: The period-averaged suicide rate for the cohort was 15.3/100,000. Firearm suicides accounted for 53% of the cases. Suicides that took place on duty occurred predominantly when personnel were alone shortly after duty commencement in the morning. Bivariate and logistic regression analyses identified psychiatric illness and a past history of deliberate self-harm, morning duty (shortly after duty assumption and consequent access to firearms), and a recent medical downgrading as independent risk factors predicting firearm suicide among military personnel. CONCLUSIONS: Occupation influences suicide method. Access to and opportunity to use lethal means in the workplace are distinct but related occupation-specific suicide risk factors in the military and in other at-risk professions. In professions where access to lethal means is inevitable, moderating opportunity for suicide is crucially important. In regular-duty military personnel, a medical downgrading, combined with risk factors established in civilians such as younger age, male gender, psychiatric illness, and past self-harm, increases the risk of suicide. The findings may be used to guide military harm-reduction strategies and have applicability in strategies for other professions at risk for workplace suicide.