Trauma-related cognitions about the self and the world have been identified as a mediator of posttraumatic stress disorder (PTSD) change during prolonged exposure (PE) therapy. However, the extent to which negative cognitions mediate PTSD change in other PTSD treatments is unclear. In addition, previous studies have not tested alternate mediators of PTSD change during PE. In a sample of 216 treatment-seeking active-duty military personnel with PTSD, the present study examined the specificity of the negative cognition mediation effect in both PE and present-centered therapy (PCT). In addition, we examined another possible mediator, cognitive emotion regulation. Lagged mediational analyses indicated that negative cognitions about the self and world and the unhelpful cognitive emotion regulation strategy of catastrophizing each significantly mediated change in PTSD from baseline to 6-month follow-up. In a combined model, the mediating effect of catastrophizing was greater than negative cognitions about the world, and similar to negative cognitions about the self. Moderated mediation analyses revealed that the effect of catastrophizing was greater in PE than in PCT. Findings show that trauma-related cognitions and, to a greater degree, the emotion regulation strategy catastrophizing, both mediate PTSD change. Further research is needed to determine whether these mediating variables represent mechanisms of therapeutic change.
Keywords: PTSD; mediation; present-centered therapy; prolonged exposure therapy; trauma-related cognitions.
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