Psychotherapy versus the combination of psychotherapy and pharmacotherapy in the treatment of depression: a meta-analysis

Background: A large number of studies have shown that psychological treatments have significant effects on depression. Although several studies have examined the relative effects of psychological and combined treatments, this has not been studied satisfactorily in recent statistical meta-analyses. Method: We conducted a meta-analysis of randomized studies in which a psychological treatment was compared to a combined treatment consisting of the same psychological treatment with a pharmacological therapy. For each of these studies we calculated the effect size indicating the difference between the psychological and the combined treatment. Results: All inclusion criteria were met by 18 studies, with a total of 1,838 subjects. The mean effect size indicating the difference between psychological and combined treatment was 0.35 (95% CI: 0.24∼0.45; P<0.001), with low heterogeneity. Subgroup analyses indicated that the difference between psychological and combined treatments was significantly smaller in studies in which cognitive behavior therapy was examined. We also found a trend (P<