Early predictors of chronic posttraumatic stress disorder symptom trajectories in U.S. Army soldiers deployed to the Iraq war zone

Abstract

Purpose The course of posttraumatic stress disorder (PTSD) symptoms varies among veterans of warzones, but sources of variation in long-term course remain poorly understood. Modeling of symptom growth trajectories facilitates understanding predictors of individual outcomes over time. Although growth mixture modeling (GMM) has been applied to military populations, few studies have incorporated both pre-deployment and follow-up measurements over an extended time.

Methods In this prospective study, 1087 US Army soldiers with varying military occupational specialties and geographic locations were assessed before and after deployment to the Iraq War, with long-term follow-up assessment occurring at least five years after return from deployment. The primary outcome variable was the PTSD Checklist, civilian version, summary score.

Results GMM yielded four latent profiles: (1) primarily asymptomatic (n = 194; 17·8%), (2) post-deployment worsening symptoms (n = 84; 7·7%), (3) mild symptoms (n = 320; 29·4%), and (4) pre-existing, with chronic post-deployment elevation of symptoms (n = 489; 45·0%). Regression models comparing the primarily asymptomatic class to symptomatic classes revealed that chronic symptom classes were associated with greater stress exposure, less pre-deployment social support, identifying as a racial/ethnic minority, military reservist or veteran status at most recent assessment, and poorer pre-deployment visual memory.

Conclusions PTSD symptom course varies considerably over time after military deployment and is associated with potentially modifiable biopsychosocial factors occurring early in its course, in addition to exposures and military status.

Trial Registration The course of posttraumatic stress disorder (PTSD) symptoms varies among veterans of war zones, but sources of variation in long-term symptom course remain poorly understood. Modeling of symptom growth trajectories facilitates the understanding of predictors of individual outcomes over time. Although growth mixture modeling (GMM) has been applied to military populations, few studies have incorporated both predeployment and follow-up measurements over an extended time. In this prospective study, 1,087 U.S. Army soldiers with varying military occupational specialties and geographic locations were assessed before and after deployment to the Iraq war zone, with long-term follow-up assessment occurring at least 5 years after return from deployment. The primary outcome variable was the PTSD Checklist–Civilian Version summary score. GMM yielded four latent profiles, characterized as primarily asymptomatic (n = 194, 17.8%); postdeployment worsening symptoms (n = 84, 7.7%); mild symptoms (n = 320, 29.4%); and preexisting, with a chronic postdeployment elevation of symptoms (n = 489, 45.0%). Regression models comparing the primarily asymptomatic class to the symptomatic classes revealed that chronic symptom classes were associated with higher degrees of stress exposure, less predeployment social support, military reservist or veteran status at the most recent assessment, and poorer predeployment visual memory, ORs = 0.98–2.90. PTSD symptom course varies considerably over time after military deployment and is associated with potentially modifiable biopsychosocial factors that occur early in its course in addition to exposures and military status.