[Cognitive therapy and interpersonal psychotherapy for major depressive disorder: how do they work, how long, and for...

Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for depression has been well established, little is known about how, how long and for whom they work.
AIM: To summarize findings from a large rct to the (differential) effects and mechanisms of change of ct/ipt for depression.
METHOD: 182 adult depressed outpatients were randomized to ct (n = 76), ipt (n = 75), or a two-month wait-list-control condition (n = 31). Primary outcome was depression severity (bdi-ii). Other outcomes were quality of life, social and general psychological functioning and various potential process measures. Interventions were compared at the end of treatment, and up to 17 months follow-up.
RESULTS: Overall, ct and ipt were both superior to the wait-list, but did not differ significantly from one another. However, the pathway through which therapeutic change occurred appeared to be different for ct and ipt, and many patients were predicted to have a clinically meaningful advantage in one of the two interventions. We did not find empirical support for the theoretical models of change.
CONCLUSION: (Long-term) outcomes of ct and ipt appear to not differ significantly. The field would benefit from further refinement of research methods to disentangle mechanisms of change, and from advances in the field of personalized medicine.