background Cognitive Behavior Therapy and Interpersonal Psychotherapy are equally effective in the treatment of depression.
aim To find out why Cognitive Behavior Therapy and Interpersonal Psychotherapy produce very similar effects and to identify the factors that lead to a successful treatment-outcome.
method We searched the literature published after 1989 using Psyclit and the key words 'cognitive behavior therapy, 'interpersonal psychotherapy' and 'depression' and then searched with the key words 'National Institute of Mental Health Treatment of Collaborative Research Program' and 'tdcrp'. A supplementary search was performed with PiCarta, based on (combinations of) the key words 'cognitive behavior therapy' and 'interpersonal psychotherapy'.
results Neither Cognitive Behavior Therapy nor Interpersonal Psychotherapy produce modality-specific effects. There are clear differences in the way treatments are administered. Patient and therapist factors that make a positive contribution to a therapeutic alliance, are strongly linked to the treatment-outcome. Some patient characteristics, however, do lead to differential treatment effects.
conclusion The lack of differential effects in patients treated with Cognitive Behavior Therapy or Interpersonal Psychotherapy seems to derive from the important role played by factors that these treatments have in common.