Adverse Childhood Experiences and New-Onset of PTSD During Military Service.

INTRODUCTION: Exposure to adverse childhood experiences (ACEs) has been increasingly recognized as a potential risk factor for later psychopathology; however, its role in the development of post-traumatic stress disorder (PTSD) during military service remains insufficiently characterized. This study aimed to examine the associations between ACE exposure and new-onset PTSD among Israeli Defense Force (IDF) recruits, and to identify an optimal ACE score threshold for PTSD risk stratification. MATERIALS AND METHODS: This retrospective cohort study included 288,663 IDF recruits who underwent pre-enlistment mental health evaluations between 2009 and 2021. Data were obtained from military health records and ACE questionnaires administered before enlistment. PTSD diagnoses assigned by military psychiatrists were tracked longitudinally from enlistment to discharge. The associations between ACE exposure and new-onset PTSD were assessed using hierarchical logistic regression and Cox proportional hazards models. ROC analysis was conducted to identify the optimal ACE score threshold for PTSD prediction. RESULTS: Of the cohort, 169 recruits (0.06%) received a PTSD diagnosis during military service, including 139 new-onset cases identified during follow-up. In multivariable analyses, combat service (OR = 2.998, P < .001) and low socioeconomic status (OR = 0.656, P = .007) were significant predictors of PTSD onset. Among individual ACE indicators, emotional neglect (OR = 2.268, P = .001) and sexual abuse (OR = 3.366, P < .001) independently predicted new-onset PTSD. ROC analysis identified an ACE score of ≥2 as the optimal threshold for PTSD prediction. Recruits with ≥2 ACEs demonstrated a nearly threefold increased risk of developing PTSD during service compared to those with one or no ACEs (HR = 2.799, P < .001). CONCLUSIONS: These findings highlight the significant role of early-life adversity in shaping PTSD risk within a military context. Specific ACE subtypes-particularly emotional neglect and sexual abuse-confer independent risk for PTSD onset during service, and an ACE score of ≥2 identifies a high-risk subgroup. Pre-enlistment ACE screening may offer a meaningful opportunity for targeted mental health surveillance and preventive intervention among recruits at elevated risk.