Cognitive models hypothesize that certain dysfunctional beliefs leading to misinterpretation of the significance of intrusions are important in the etiology and maintenance of obsessive-compulsive disorder (OCD). There is no consensus about which characteristics of OCD patients more likely to be associated with better treatment response.

We aimed to investigate whether obsessive beliefs change over time in the OCD patients receiving Serotonin Reuptake Inhibitors. We also investigated the effect of change in obsessive beliefs on psychopharmacological treatment response.

A sample of 75 patients with OCD were interviewed the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and Hamilton Depression Rating Scale (HDRS). To measure dysfunctional beliefs, they were administered the Obsessive Beliefs Questionnaire-44 (OBQ-44) which contains three subscales; threat overestimation and responsibility, importance and control of intrusive thoughts, and perfectionism and need for certainty.

The seventy-six percent (n=57) patients completed the treatment period and they were reassessed after 12 weeks with the Y-BOCS, HDRS and OBQ-44. The mean change scores of responders for OBQ-44 Responsibility/Threat Estimation and OBQ-44 Perfectionism/Certainty were not significantly differing from those of non-responders. The mean change in responders for OBQ-44 Importance/Control of Thoughts and HDRS were significantly higher than non responders.

Our results suggest that treatment response to pharmacotherapy in OCD is negatively associated with the obsessive beliefs about perfectionism and certainty. The alleviation of negative mood by SRIs may not allow the sufferer disengages from dysfunctional appraisals.