Exposure and Response (Ritual) Prevention for Obsessive Compulsive Disorder FOA, EDNA B. (PROFESOR OF CLINICAL PSYCHOLOGY IN PSYCHIATRY, UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA, PENNSYLVANIA, USA),YADIN, ELNA (PSYCHOLOGIST AND DIRECTOR OF THE OCD CLINIC, CENTER FOR THE TREATMENT AND STUDY OF ANXIETY (CTSA), UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA, PENNSYLVANIA, USA),LICHNER, TRACEY K. (PSYCHOLOGY AND DIRECTOR OF SUPERVISION, CENTER FOR THE TREATMENT AND STUDY OF ANXIETY (CTSA), UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA, PENNSYLVANIA, USA)