Group therapy is an efficacious treatment for patients suffering from obsessive-compulsive disorder (OCD). Especially Cognitive-Behavioral Therapy (CBT) approaches are well examined (Schwartze et al., 2016). For this disorder, we considered systematic reviews and meta-analyses only, published from 1990 on with no restrictions on publication language and involving adult patients (>= 18 years) with a diagnosis of OCD according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R, DSM-IV, DSM-IV-TR; American Psychiatric Association 1987, 1994, 2000) or the International Classification of Diseases (ICD-10; World Health Organization, 1992). Additionally, studies must have been based upon a psychotherapeutic formal change theory, performed by a professional group leader or therapist in groups comprising at least three patients, lasting at least for five sessions. Eligible control groups were “no treatment/wait-list control”, “treatment as usual”, “common factor control”, “individual psychotherapy” as well as “pharmacotherapy”. Clinician-rated symptom severity was considered as the primary outcome.

Each disorder included had more than 2 trials given the amount of research attention OCD has received. One caution about the evidence is the inclusion of not randomized-controlled trials only which limits the establishment of causal associations and thereby the level of evidence (Zabor et al., 2020).

Most studies and resources relate to CBT. Fewer studies examined group behavioral therapy (exposure with response prevention) or group cognitive therapy. However, these also show proven efficacy.

Most of the included resources were designed for individual therapy. However, they can be usefully applied in a group setting.