Prospective examination of pre-trauma anhedonia as a risk factor for post-traumatic stress symptoms

Anhedonia in US Marines significantly increased following combat deployment. Anhedonia was associated with re-experiencing symptoms cross-sectionally. Anhedonia was associated with re-experiencing symptoms prospectively. Anhedonia was associated more strongly with re-experiencing compared to depression. Anhedonia, the reduction of pleasure and reward-seeking behaviour, is a transdiagnostic symptom with well-described neural circuit mediators. Although typically observed during disease state, extant hypotheses suggest that anhedonia may also be an early risk factor for development of psychopathology. Understanding the contribution of anhedonia to the trauma-response trajectory may bolster inferences about biological mechanisms contributing to pre-trauma risk versus trauma-related symptom expression, knowledge of which could aid in targeted interventions. Using a prospective, longitudinal design in a population at risk for trauma disorders, we tested the hypothesis that anhedonia may be a pre-trauma risk factor for post-traumatic stress disorder (PTSD) symptoms. Adult male participants from the Marine Resilience Study (N = 2,593) were assessed across three time-points (pre-deployment, 3-month and 6-month post-deployment). An anhedonia factor was extracted from self-report instruments pre-trauma and tested for its relationship with development of PTSD re-experiencing symptoms after deployment. Higher pre-deployment anhedonia predicted increased PTSD intrusive re-experiencing symptoms at 3- and 6-months post-deployment when controlling for pre-trauma PTSD and depression symptoms. Depression symptoms were not significant predictors of subsequent PTSD intrusive re-experiencing symptoms. Anhedonia at 3 mo also robustly predicted maintenance of PTSD intrusive re-experiencing symptoms at the 6 mo time point. Pre-deployment anhedonia may be a pre-trauma risk factor for PTSD, not simply a state-dependent effect of trauma exposure and PTSD symptom expression. Anhedonia may contribute to persistence and/or chronicity of re-experiencing symptoms after the emergence of PTSD symptoms.