Group Psychotherapy Efficacy: A Meta-Analytic Perspective.

Analyses of the efficacy of group psychotherapy indicate that group therapy demonstrates, in a majority of reviews, significant improvement over inert comparison groups and proves comparable or superior to other active treatment conditions. Because group therapy is a viable cost-efficient treatment option being used with increasing regularity among diverse populations, and with varying structural formats, a central task demanding attention is careful analysis of the differential effectiveness of group therapy across treatment variations or dimensions. Using a common measuring standard called an effect size, meta analyses can represent the average amount of change one could expect in the average client who receives a given treatment. The present study sought to explore systematically the relationships between improvement rates in group psychotherapy (effect size) and several treatment, therapist, client, and methodological variables using meta-analytic techniques. The review was based on the cumulative results of 12 years of group psychotherapy outcome literature. Results were reported on: component characteristics; post treatment change comparisons--treatment type comparison with wait-list controls, group treatment type comparison, outcome source comparison on post-treatment change, and outcome content comparison on post-treatment change; and pre- post-treatment change comparisons--client population/diagnosis client gender, composition, and attrition. Contains 47 references. (JBJ)