Association Between Responsibility for the Death of Others and Postdeployment Mental Health and Functioning in US Soldiers

IMPORTANCE: Rates of suicidal thoughts and behaviors (STBs) in US soldiers have increased sharply since the terrorist attacks on September 11, 2001, and postdeployment posttraumatic stress disorder (PTSD) remains a concern. Studies show that soldiers with greater combat exposure are at an increased risk for adverse mental health outcomes, but little research has been conducted on the specific exposure of responsibility for the death of others. OBJECTIVE: To examine the association between responsibility for the death of others in combat and mental health outcomes among active-duty US Army personnel at 2 to 3 months and 8 to 9 months postdeployment. DESIGN, SETTING, AND PARTICIPANTS: This cohort study obtained data from a prospective 4-wave survey study of 3 US Army brigade combat teams that deployed to Afghanistan in 2012. The sample was restricted to soldiers with data at all 4 waves (1-2 months predeployment, and 2-3 weeks, 2-3 months, and 8-9 months postdeployment). Data analysis was performed from December 12, 2020, to April 23, 2021. MAIN OUTCOMES AND MEASURES: Primary outcomes were past-30-day PTSD, major depressive episode, STBs, and functional impairment at 2 to 3 vs 8 to 9 months postdeployment. Combat exposures were assessed using a combat stress scale. The association of responsibility for the death of others during combat was tested using separate multivariable logistic regression models per outcome adjusted for age, sex, race and ethnicity, marital status, brigade combat team, predeployment lifetime internalizing and externalizing disorders, and combat stress severity. RESULTS: A total of 4645 US soldiers (mean [SD] age, 26.27 [6.07] years; 4358 men [94.0%]) were included in this study. After returning from Afghanistan, 22.8% of soldiers (n = 1057) reported responsibility for the death of others in combat. This responsibility was not associated with any outcome at 2 to 3 months postdeployment (PTSD odds ratio [OR]: 1.23 [95% CI, 0.93-1.63]; P = .14; STB OR: 1.19 [95% CI, 0.84-1.68]; P = .33; major depressive episode OR: 1.03 [95% CI, 0.73-1.45]; P = .87; and functional impairment OR: 1.12 [95% CI, 0.94-1.34]; P = .19). However, responsibility was associated with increased risk for PTSD (OR, 1.42; 95% CI, 1.09-1.86; P = .01) and STBs (OR, 1.55; 95% CI, 1.03-2.33; P = .04) at 8 to 9 months postdeployment. Responsibility was not associated with major depressive episode (OR, 1.30; 95% CI, 0.93-1.81; P = .13) or functional impairment (OR, 1.13; 95% CI, 0.94-1.36; P = .19). When examining enemy combatant death only, the pattern of results was unchanged for PTSD (OR, 1.44; 95 CI%, 1.10-1.90; P = .009) and attenuated for STBs (OR, 1.46; 95 CI%, 0.97- 2.20; P = .07). CONCLUSIONS AND RELEVANCE: This cohort study found an association between being responsible for the death of others in combat and PTSD and STB at 8 to 9 months, but not 2 to 3 months, postdeployment in active-duty soldiers. The results suggest that delivering early intervention to those who report such responsibility may mitigate the subsequent occurrence of PTSD and STBs.