Predicting externalizing symptom trajectories in U.S. National Guard recruits: The role of adverse childhood experiences.

Adverse childhood experiences (ACEs) are strongly associated with increased risk of externalizing problems. Despite their prevalence in military populations, limited research links ACEs to longitudinal externalizing problem trajectories during military service transition. This study aimed to identify distinct trajectories of externalizing problems (deviant behavior, alcohol use, and drug use) in U.S. Army National Guard recruits and examine how baseline ACEs predict membership in higher-risk trajectories during the transition to military service. A longitudinal cohort of 707 Army National Guard recruits was assessed before basic combat training and at four follow-ups over 18 months. Growth mixture modeling was used to identify distinct trajectories for deviant behavior, alcohol use, and drug use, whereas logistic regression analyses were conducted to examine associations between baseline ACEs and trajectory group membership. For each domain, we identified distinct trajectory patterns beyond stable-low: decreasing-increasing and increasing-decreasing deviant behavior trajectories, stable-high and increasing alcohol use trajectories, and a variable drug-users trajectory. Relative to stable-low class membership, higher ACE scores were associated with increased odds of membership in the decreasing-increasing, OR = 1.26, 95% CI [1.12, 1.41], and increasing-decreasing, OR = 1.26, 95% CI [1.15, 1.37], deviant behavior; stable-high alcohol, OR = 1.13, 95% CI [1.03, 1.25]; and drug-users, OR = 1.19, 95% CI [1.11, 1.28], trajectories. Specific ACEs uniquely predicted higher-risk trajectories. These findings suggest that ACEs may have longitudinal effects on the unfolding of externalizing symptom trajectories among military recruits, highlighting the need to address preexisting developmental vulnerabilities when examining pathways to psychopathology during significant life transitions.