Driessen, E., Van, H.L., Don, F.J., Peen, J., Kool, S. ....Dekker, J.J. (2013). The efficacy of cognitive-behavioral therapy and psychodynamic therapy in the outpatient treatment of major depression: A randomized clinical trial. American Journal of Psychiatry, 170, 1041-1050.
Psychotherapy is one of the most widely used treatments for major depression. Unfortunately there is no commercial entity like the pharmaceutical industry to support research and development of psychotherapy. As a result, researchers have limited ability to conduct larger-scale studies of comparative treatment effectiveness, of which there are only a handful. Although psychodynamic therapy (PDT) has been used to treat depressed patients for decades, randomized controlled trials of its efficacy are relatively infrequent. A concurrent problem with outcome research in psychotherapy is that sample sizes tend to be too small to actually test if two treatments are equivalent in what is called an “equivalency trial”. Without large samples, all one can conclude is that two treatments are “not significantly different” (a statistical note: an equivalency trial is planned from the outset to have a large enough sample to test the hypothesis that, with 95% certainty, the effect of one treatment falls within a narrow, predetermined margin of the effect of another treatment). The study by Driessen and colleagues was conducted in several sites in Amsterdam, in which 341 patients seeking outpatient psychotherapy for depression in psychiatric clinics were randomized to PDT or cognitive behavioural therapy (CBT). This is largest trial ever of PDT. Participants received 16 weeks of therapy and then were followed up for 1 year. About 40% of patients started with severe depression. Therapists were 93 experienced and well trained therapists who provided one of the two treatments. The main outcome was remission from depression, defined by achieving a low score on a validated observer rating scale. Post treatment remission rates were 21% for CBT and 24% for PDT, indicating that the treatments were equivalent.
Cognitive-behavioral therapy (CBT) and short-term PDT provided similar outcomes for patients with a major depressive episode, but remission rates at the end of treatment were low for both treatments. Lower remission rates were likely due to the greater level of severity for these patients compared to those seen in primary care settings. The results highlight that even the best available psychological (and pharmacological) treatments yield modest outcomes for more severely depressed patients. Nevertheless, this rare equivalency trial found that both CBT and PDT were equivalent in terms of outcomes for these patients.
Author email: firstname.lastname@example.org