The Yale-Brown Obsessive Compulsive Scale: interview versus self-report.

Several studies have demonstrated the reliability and validity of the Yale-Brown Obsessive Compulsive Scale (YBOCS) conducted by trained interviewers. The present study examined several aspects of a self-report YBOCS version relative to the usual interview format in two non-clinical samples (ns = 46 and 70) and in a clinical OCD sample (n = 36) and a clinical non-OCD group (n = 10). The self-rated instrument showed excellent internal consistency and test-retest reliability, performing somewhat better than the interview. There was good agreement between symptom checklist categories across the two versions, though clinical subjects reported more symptoms on the self-report form than on the interview. Some order effects were evident for non-clinical subjects only: those who received the self-report first scored lower on both self-report and interview than those who received the interview first. No order effects were observed in the clinical sample. The self-report version showed strong convergent validity with the interview, and discriminated well between OCD and non-OCD patients. Although more study is needed, particularly on clinical samples, these findings suggest that the self-report YBOCS may be a time-saving and less costly substitute for the interview format in assessing OCD symptoms.