Non-suicidal self-injury prevalence, course, and association with suicidal thoughts and behaviors in two large, representative samples of US Army soldiers

BackgroundNon-suicidal self-injury (NSSI) prospectively predicts suicidal thoughts and behaviors in civilian populations. Despite high rates of suicide among US military members, little is known about the prevalence and course of NSSI, or how NSSI relates to suicidal thoughts and behaviors, in military personnel.MethodsWe conducted secondary analyses of two representative surveys of active-duty soldiers (N = 21 449) and newly enlisted soldiers (N = 38 507) from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS).ResultsThe lifetime prevalence of NSSI is 6.3% (1.2% 12-month prevalence) in active-duty soldiers and 7.9% (1.3% 12-month prevalence) in new soldiers. Demographic risk factors for lifetime NSSI include female sex, younger age, non-Hispanic white ethnicity, never having married, and lower educational attainment. The association of NSSI with temporally primary internalizing and externalizing disorders varies by service history (new v. active-duty soldiers) and gender (men v. women). In both active-duty and new soldiers, NSSI is associated with increased odds of subsequent onset of suicidal ideation [adjusted odds ratio (OR) = 1.66-1.81] and suicide attempts (adjusted OR = 2.02-2.43), although not with the transition from ideation to attempt (adjusted OR = 0.92-1.36). Soldiers with a history of NSSI are more likely to have made multiple suicide attempts, compared with soldiers without NSSI.ConclusionsNSSI is prevalent among US Army soldiers and is associated with significantly increased odds of later suicidal thoughts and behaviors, even after NSSI has resolved. Suicide risk assessments in military populations should screen for history of NSSI.