The evolution of mental health outcomes across a combat deployment cycle: A longitudinal study of a Guam-based National Guard unit

Sustained overseas military operations over the last two decades have resulted in large numbers of United States and Allied servicemembers being faced with multiple unique occupational and environmental stressors, from serving in a combat zone, to having to be away from family and home for long periods of time. These stressors result in numerous negative health (physical and mental) and behavioral outcomes. Whereas there is a substantial amount of research focused on deployment-related health outcomes within active duty military populations, reserve forces are less understood. This study focuses on a United States Army National Guard combat unit before, during and after a deployment to Afghanistan. This prospective longitudinal study, conducted over the course of an operational deployment cycle (i.e., before, during and after), documents the trajectories of salient mental health outcomes (i.e., post-traumatic stress, depression, general anxiety, and aggression). The findings show that both combat (e.g., killing others) and non-combat (e.g., boredom) stressors negatively affect mental health outcomes, and the severity of these outcomes increases over the course of a deployment cycle. Of special note, the study reveals key gender differences in the evolution of PTSD, depression and anxiety across a deployment cycle: females report increased PTSD, depression and anxiety 6 months post-deployment whereas the levels reported by males stabilize at their mid-deployment levels. The findings offer insights for medical providers and policymakers in developing more targeted health promotion campaigns and interventions, especially during the post-deployment phase.