The Main and Interactive Effects of Distress Tolerance and Reward Function on Posttraumatic Stress Disorder Symptoms Among Firefighters

Background: Firefighters are at heightened risk of posttraumatic stress disorder (PTSD), underscoring the importance of understanding clinically targetable factors to inform evidence-based intervention development. Hedonic capacity, or the ability to experience pleasure, is a facet of reward functioning. Anhedonia (i.e., low or absent hedonic capacity) is a hallmark symptom of PTSD. Distress tolerance (DT), or the perceived ability to withstand negative emotional states, has also demonstrated associations with PTSD. Objective: The purpose of the present study was to examine the main and interactive effects of self-reported hedonic capacity (Snaith-Hamilton Pleasure Scale) and DT (Distress Tolerance Scale) on PTSD symptom severity among firefighters. Method: A hierarchical linear regression was performed among a sample of 802 trauma-exposed career firefighters, who completed a battery of self-report questionnaires. Covariates included trauma load (i.e., number of trauma types), years in the fire service, and depression symptoms (excluding anhedonia). Results: Both hedonic capacity (B = 2.71, SE = .95, p = .005) and DT (B = -.21, SE = .03, p < .001) were incrementally associated with PTSD symptom severity. The interactive effect of hedonic capacity and DT was associated with heightened PTSD symptom severity (B = .25, SE = .07, p < .001). Conclusions: Hedonic capacity and DT were independently and transactionally associated with heightened PTSD symptom severity among trauma-exposed firefighters. These findings provide evidence for the utility in developing interventions that target DT and impaired hedonic capacity among firefighters, particularly those experiencing PTSD symptomatology. Clinical Impact Statement Results suggest that firefighters with PTSD symptoms may benefit from treatments that address an individual's ability to tolerate distress and/or their capacity to experience pleasure.