EFFECTS OF TREATMENT DURATION AND SEVERITY OF DEPRESSION ON THE EFFECTIVENESS OF COGNITIVE-BEHAVIORAL AND PSYCHODYNAMIC INTERPERSONAL PSYCHOTHERAPY

A total of 117 depressed clients, stratified for severity, completed 8 or 16 sessions of manualized treatment, either cognitive-behavioral p sychotherapy (CB) or psychodynamic-interpersonal psychotherapy (PI). E ach of 5 clinician-investigators treated clients in all 4 treatment co nditions. On most measures, CB and PI were equally effective, irrespec tive of the severity of depression or the duration of treatment. Howev er, there was evidence of some advantage to CB on the Beck Depression Inventory (Beck, Ward, Mendelson, Mock, & Erbaugh, 1961). There was no evidence that CB's effects were more rapid than those of PI, nor did the effects of each treatment method vary according to the severity of depression. There was no overall advantage to 16-session treatment ov er 8-session treatment. However, those presenting with relatively seve re depression improved substantially more after 16 than after 8 sessio ns.