(PS4-A2) Examining the Comorbidity of PTSD and OCD: Symptoms and Cognitions

Despite the co-occurrence of posttraumatic stress disorder (PTSD) and obsessive-compulsive disorder (OCD), there is limited research on the nature of this comorbidity. Cognitive behavioral models of PTSD and OCD posit that dysfunctional cognitions contribute to both disorders. Obsessions and compulsions can also develop as a means of coping with posttraumatic stress symptoms (PTSS). The present study examined how aspects of PTSS and posttraumatic cognitions relate to OC symptom dimensions (i.e., contamination, responsibility for harm, unacceptable thoughts, symmetry) in a community sample of 329 individuals with a Criterion A trauma (M age = 24.41, SD = 12.46).

Participants completed the following measures: Posttraumatic Diagnostic Scale for DSM-5 (PDS-5), Dimensional Obsessive-Compulsive Scale (DOCS), and Posttraumatic Cognitions Inventory (PTCI; subscales include self-blame, negative cognitions about oneself, and negative cognitions about the world). PTSS clusters were measured using the subscale scores of the PDS-5 (reexperiencing, avoidance, changes in mood and cognition, and arousal and hyperarousal). Hierarchical linear regressions were performed with the DOCS subscales as the dependent variables. Gender was entered in Step 1, the PTCI subscales in Step 2, and the PDS-5 subscales in Step 3.

The overall regression predicting DOCS-Contamination was significant, accounting for 5.8% of the variance, (F (8, 317) = 2.42, p = .02), with hyperarousal emerging as a significant individual predictor (β = .21, p = .03). The regression predicting DOCS-Responsibility for Harm accounted for 29.5% of the variance (F (8, 317) = 16.62, p < .001), with hyperarousal (β = .25, p = .003) and posttraumatic cognitions about oneself (β = .30, p < .001) emerging as significant individual predictors. The regression predicting DOCS-Unacceptable Thoughts accounted for 29.5% of the variance, (F (8, 317) = 28.79, p < .001), with hyperarousal (β = .16, p = .04) and posttraumatic cognitions about oneself (β = .32, p < .001) and the world (β = .14, p = .03) emerging as significant individual predictors. Finally, the regression predicting DOCS-Symmetry was also significant, accounting for 15% of the variance (F (8, 317) = 6.97, p < .001), with reexperiencing symptoms (β = .22, p = .01) emerging as a significant individual predictor.

These results suggest that dysfunctional trauma-related cognitions, hyperarousal, and reexperiencing symptoms play a role in the co-occurrence of PTSS and OCS. Additionally, certain posttraumatic cognitions and PTSS symptom clusters appear to be differentially related to the four OC symptom dimensions. Further research examining mechanisms of co-occurrence is critical to improving treatment for individuals with co-occurring PTSS and OCS.