Thematic similarity and clinical outcome in obsessive-compulsive disorder group treatment.

Despite the existence of efficacious cognitive-behavioral group treatments for obsessive-compulsive disorder (OCD), no data has been presented regarding the potential impact of symptom or thematic similarity among group members. The purpose of this study was to evaluate the effect of thematic similarity among group members on outcome after cognitive-behavioral (CBT) or exposure/response prevention (ERP) treatment for OCD. Results consistently demonstrated across a range of measures no impact of thematic similarity, nor any interaction of similarity by treatment type (ERP versus CBT), on treatment outcome. These data suggest that OCD treatment groups can be formed based on consecutive client intake without negatively impacting efficacy.