Do Changes in Dysfunctional Posttraumatic Cognitions Differentially Predict PTSD Symptom Clusters?

Objective: In recent years, it has been suggested that the modification of dysfunctional posttraumatic cognitions plays a central role as a mechanism of change in cognitive behavioral therapy (CBT) for posttraumatic stress disorder (PTSD). Indeed, several studies have shown that changes in dysfunctional posttraumatic cognitions precede and predict symptom change. However, these studies have investigated the influence on overall symptom severity-despite the well-known multidimensionality of PTSD. The present study therefore aimed to explore differential associations between change in dysfunctional conditions and change in PTSD symptom clusters. Method: As part of a naturalistic effectiveness study evaluating trauma-focused cognitive behavioral therapy for PTSD in routine clinical care, 61 patients with PTSD filled out measures of dysfunctional posttraumatic cognitions and PTSD symptom severity every five sessions during the course of treatment. Lagged associations between dysfunctional cognitions and symptom severity at the following timepoint were examined using linear mixed models. Results: Over the course of therapy, both dysfunctional cognitions and PTSD symptoms decreased. Posttraumatic cognitions predicted subsequent total PTSD symptom severity, although this effect was at least partly explained by the time factor. Moreover, dysfunctional cognitions predicted three out of four symptom clusters as expected. However, these effects were no longer statistically significant when the general effect for time was controlled for. Conclusion: The present study provides preliminary evidence that dysfunctional posttraumatic cognitions predict PTSD symptom clusters differentially. However, different findings when employing a traditional versus a more rigorous statistical approach make interpretation of findings difficult.