Background: There remains considerable disagreement regarding the relative efficacy of psychotherapy and medication across types of depression.
Method: We used random effects meta-analysis to examine the relative efficacy of psychotherapy vis-à-vis medication at post-treatment and follow-up. We also estimated the relative efficacy of continued medication versus discontinued psychotherapy. As twenty-eight studies (39 effects, n=3,381) met inclusion criteria, we were able to conduct an adequately powered test of between-study heterogeneity and examine if the type of depression influenced relative efficacy.
Results: Psychotherapy and medication were not significantly different at post-treatment, however effect sizes were not consistent. Although there was no association between severity and relative efficacy, a small but significant advantage for medications in the treatment of dysthymia did emerge. However, psychotherapy showed a significant advantage over medication at follow-up and this advantage was positively associated with length of follow-up. Moreover, discontinued acute phase psychotherapy did not differ from continued medication at follow-up.
Limitations: Limitations included relatively fewer studies of severe and chronic depression, as well as dysthymia. In addition, only a minority of studies reported follow-up data.
Conclusions: Our results indicated that both psychotherapy and medication are viable treatments for unipolar depression and that psychotherapy may offer a prophylactic effect not provided by medication. However, our analyses diverged from previous findings in that effects were not consistent and medication was significantly more efficacious than psychotherapy in the treatment of dysthymia.