Recent Developments in Group Psychotherapy Research.

This article reviews group psychotherapy research published within the past 30 years, predominantly focusing on outcomes of group treatments for patients with various mental disorders. Additionally, meta-analyses on the efficacy of group treatments for patients with cancer or chronic pain are summarized. Results strongly support the use of group therapy and demonstrate outcomes equivalent to those of individual psychotherapy. The research also appears to emphasize the effect of feedback on outcomes in group treatments and an association between treatment outcomes and group cohesion and alliance. Other promising developments in the field of group therapy are discussed.