The relative effectiveness of Cognitive Behavioral Therapy (CBT) in alleviating depression has been declining steadily for the past 40 years, according to a study in Psychological Bulletin.
Authors Tom Johnsen and Oddgeir Friborg examined data from 70 studies between 1977 and 2014 involving 2,426 people diagnosed with depression. The effect sizes were quantified based on the Beck Depression Inventory (BDI) and the Hamilton Rating Scale for Depression (HRSD), and rates of remission were also factored in.
“The main finding was that the treatment effect of CBT showed a declining trend across time and across both measures of depression (the BDI and the HRSD),” wrote the authors. “Contemporary clinical treatment trials therefore, seem to be less effective than the therapies conducted decades ago.”
The authors examined the results from many angles and considered many different possibilities for what may be affecting these outcomes. In the main, they suggested that the “placebo effect” of CBT as a potential cure for depression may be waning. “(I)t is not inconceivable that patients’ hope and faith in the efficacy of CBT has decreased somewhat, in recent decades.” They added, “Moreover, whether widespread knowledge of the present meta-analysis results might worsen the situation, remains an open question.”
Johnsen, Tom J., and Oddgeir Friborg. “The Effects of Cognitive Behavioral Therapy as an Anti-Depressive Treatment Is Falling: A Meta-Analysis.” Psychological Bulletin, May 11, 2015. doi:10.1037/bul0000015. (Abstract) (Full text)
Is CBT for depression losing its efficacy? (BPS Research Digest, June 8, 2015)