Background: Standardised effect sizes have been criticized because they are difficult to interpret and offer little clinical information. This meta-analyses examine the extent of actual improvement, the absolute numbers of patients no longer meeting criteria for major depression, and absolute rates of response and remission.
Methods: We conducted a meta-analysis of 92 studies with 181 conditions (134 psychotherapy and 47 control conditions) with 6937 patients meeting criteria for major depressive disorder. Within these conditions, we calculated the absolute number of patients no longer meeting criteria for major depression, rates of response and remission, and the absolute reduction on the BDI, BDI-II, and HAM-D.
Results: After treatment, 62% of patients no longer met criteria for MDD in the psychotherapy conditions. However, 43% of participants in the control conditions and 48% of people in the care-as-usual conditions no longer met criteria for MDD, suggesting that the additional value of psychotherapy compared to care-as-usual would be 14%. For response and remission, comparable results were found, with less than half of the patients meeting criteria for response and remission after psychotherapy. Additionally, a considerable proportion of response and remission was also found in control conditions. In the psychotherapy conditions, scores on the BDI were reduced by 13.42 points, 15.12 points on the BDI-II, and 10.28 points on the HAM-D. In the control conditions, these reductions were 4.56, 4.68, and 5.29.
Discussion: Psychotherapy contributes to improvement in depressed patients, but improvement in control conditions is also considerable.
Keywords: Cognitive-behavior therapy; Interpersonal psychotherapy; Meta-analysis; Psychotherapy; Remission; Response.
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