Review The effectiveness of group cognitive behaviour therapy for unipolar depressive disorders Tian P.S. Oei a,b, ⁎ , Genevieve Dingle a a School of Psychology, University of Queensland, Brisbane, Australia, 4072 b CBT Unit, Toowong Private Hospital, University of Queensland, Brisbane, Australia, 4072 Received 21 July 2006; received in revised form 12 July 2007; accepted 15 July 2007 Available online 22 August 2007 Abstract This paper evaluates the effectiveness of group cognitive behaviour therapy (GCBT) as an intervention for unipolar depressive disorders. PsychINFO and PubMed databases were selected to generate the 34 papers used for this review. Our results showed that effect sizes for GCBT over the control conditions range from small (0.1) to large (2.87) with the mean effect size of 1.10. The pre- post treatment effect sizes for GCBT range from 0.30 to 3.72 with a mean of 1.30. Convergent evidence was demonstrated across different outcome measures of GCBT. Our findings indicated that GCBT yielded outcomes better than no-treatment controls and was comparable with other treatments (including both bona fide and non-bona fide comparison treatments). It was concluded that GCBT was effective for the treatment of Unipolar depression and thus can be used with confidence. There is now an urgent need to develop and evaluate a coherent GCBT theory, in particular the roles of group processes in GCBT, before further major advancement in this area can be made. © 2007 Elsevier B.V. All rights reserved. Keywords: Cognitive behavioral therapy; Depression; Group processes; Group therapy; Mood disorder Contents 1. The effectiveness of GCBT for unipolar depressive disorders .............................. 0 2. Method ......................................................... 0 2.1. Selection of studies ................................................ 0 2.2. Description of studies reviewed ......................................... 0 2.3. Types of control condition used ......................................... 0 2.4. Effect size calculations .............................................. 0 3. Results .......................................................... 0 3.1. Description of studies included in the review ................................... 0 3.2. Outcome measures ................................................ 0 3.3. Effect sizes .................................................... 0 3.4. Comparison with other treatments ........................................ 0 Journal of Affective Disorders 107 (2008) 5 – 21 www.elsevier.com/locate/jad ⁎ Corresponding author. School of Psychology, University of Queensland, Brisbane, Australia, 4072. Tel.: +61 7 3365 6449. E-mail address: oei@psy.uq.edu.au (T.P.S. Oei). 6 12 12 12 12 13 13 13 13 14 14 0165-0327/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2007.07.018