Conventional wisdom suggests that repeated traumatic exposure should strongly relate to increased posttraumatic stress disorder (PTSD) symptoms. However, research with first responders, who are repeatedly exposed to traumatic events, finds inconsistent links to PTSD. Although recent studies explored associations between general self-reported emotion-regulation and PTSD, the present study was the first to test the moderating role of regulatory choice flexibility, the ability to choose regulatory options that suit contextual demands. A total of 69 firefighters with differing dutyrelated traumatic-exposure were tested on an innovative performance-based regulatory choice flexibility paradigm and evaluated for PTSD symptoms using clinical interviews. We predicted and found that firefighters with low but not high regulatory choice flexibility showed a significant positive correlation between traumatic exposure and PTSD symptoms. This moderation was specific to PTSD symptoms and contributed above and beyond other well-established correlates of PTSD. The results suggest that regulatory choice flexibility can intersect the deleterious link between traumatic exposure and PTSD symptoms.

Clinical improvement in individuals with PTSD was associated with increased expression of FKBP5 and increased hippocampal volume, which were positively correlated.

Reduced hippocampal volume may account for the difficulty of individuals with PTSD to differentiate negative and novel conditions and hence may facilitate reexperiencing symptoms.