Efficacy of cognitive -behavioral, pharmacological, and combined treatments of depression: A meta-analysis

The objective of the present study was to compare the efficacy of cognitive-behavioral (CBT), pharmacological (PT), and the combined treatments (CT) of depression using meta-analysis. A total of 57 studies (total number of patients = 9,375) met the inclusion criteria. The effect size analyses of symptom reduction based on the Hamilton Rating Scale for Depression (HAM-D; Hamilton, 1960) revealed that CBT was more efficacious than the controlled condition (i.e., no-treatment or waiting list), with a large Cohen's d effect size of -0.83. PT was more efficacious than the controlled condition, with a small Cohen's d effect size of -0.41. There was no difference in the efficacy between CBT and PT, with a small Cohen's d effect size of -0.13. CT was more efficacious than PT and CBT, both with a medium Cohen's d effect size of -0.53. The findings supported the enhancing effect of CT.;Analyses of moderator variables showed that longer treatment duration and individual therapy were associated with more favorable outcomes in CBT, and higher level of initial symptom severity was associated with more favorable outcome in PT. The comparison of the number of dropout patients showed no differences between any of the three treatment approaches. However, dropout is an important issue related to treatment efficacy, and more research is needed to prevent dropout. The results indicated that depression can be treated and CT appears to be the most promising approach. Future research should focus on the mechanisms responsible for the enhancement effect of CT and on the differences between simultaneous versus sequential administration. Future research should also focus on the application of CT to different patient populations.