BACKGROUND: Individual Cognitive Behavioural Therapy (CBT) is considered an empirically supported treatment for OCD. Group therapy has been proposed in the treatment of OCD, but it is still uncertain whether it is as effective as individual therapy. Most outcome researchers of individual therapy, as well as reviewers of the literature have focused on within single treatments effect sizes rather between group effect sizes. OBJECTIVES To make a systematic review, and by methods of meta analysis compute a pooled within effect size of studies of group CBT of OCD and compare these to previously reported within effect sizes of individual treatment studies. A second objective was to compute a between group effect size, relying solely on randomised studies comparing group therapy to waitlist control. METHOD A systematic literature search was conducted and included studies were divided into three categories based on their study design. RESULTS Thirteen studies with a total of 828 participants fulfilled the inclusion criteria; four randomizes control studies, four non randomizes comparative studies and 7 naturalistic studies. The pooled within effect sizes for each category were found to be 1.31; 1.05 and 1.25 respectively, with an overall combined pooled within effect size across the categories at 1.18. Finally a between effect sizes of the four studies comparing group therapy to waitlist control group was reported at.1.12 CONCLUSION The reported within effect sizes in this meta-analysis (range 1.05 - 1.36) are comparable to reported within effect sizes of individual therapy ranging from d = 1.02 to d = 1.46. Based solely on calculations of effect sizes these results show that group therapy is equally effective to individual therapy.
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The 5th World Congress of Behavioural & Cognitive Therapies, 2007