Yale-Brown Obsessive Compulsive Scale: Are self-rating and interview equivalent measures?

Aim: We compared the self-report rating scale of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) with the Y-BOCS interview in an inpatient sample of 28 patients with obsessive-compulsive disorder. Method: All patients completed the Y-BOCS self-rating scale. Afterwards they participated in an Y-BOCS interview with one of four experienced raters, who rated them without knowledge of the self rating-scores of the patient. At the end of treatment the procedure was repeated. Results: The agreement between both Y-BOCS versions measured by intra-class-correlation (ICC) was 0,83 at the beginning of the inpatient treatment. At the end of treatment, agreement rose to 0,93. Conclusions: Proceeding from considerations based on these data it is recommended to consider both Y-BOCS versions as interchangeable in the computation of group statistics even for moderate sample sizes, which implies economic and practical advantages for the organization of research projects. On the other hand, if individual Y-BOCS scores are important, the interview should be preferred.