Psychological distress across the deployment cycle: exploratory growth mixture model

Background Prior research has identified behavioural health outcomes as key sequelae to combat deployment. However, relatively little is known about differential patterns of change in depression or generalised anxiety linked to deployment to a combat zone. In this paper, we add to the existing trajectory literature and examine key predictive factors of behavioural health risk. Aims The primary aim is to leverage growth mixture modelling to ascertain trajectories of psychological distress, operationalised as a coherent construct combining depression and generalised anxiety, and to identify factors that differentiate adaptive and maladaptive patterns of change. Method Data were collected from a brigade combat team prior to a combat deployment to Afghanistan, during deployment, at immediate re-integration and approximately 2–3 months thereafter. The main outcome was measured using the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS). Results Three latent trajectories were identified: a low–stable trajectory, a declining trajectory and a rising trajectory. Most individuals aligned with the low–stable trajectory. A conditional model using covariates measured during deployment showed that the low–stable trajectory differed consistently from the remaining trajectories on self-reported loneliness and non-combat deployment stressors. Conclusions The examination of differential patterns of adaptation, to identify individuals at higher risk, is critical for the efficient targeting of resources. Our findings further indicate that loneliness may be a useful leverage point for clinical and organisational intervention.