Effects of treatment duration and severity of depression on the maintenance of gains after cognitive-behavioral and psychodynamic-interpersonal psychotherapy.

One hundred four clients completed a mailed follow-up 1 year after completing 8 of 16 sessions of treatment, either cognitive-behavioral (CB) or psychodynamic-interpersonal (PI) psychotherapy. Although mean scores on outcome measures at 1 year suggested that gains were, in general, well maintained, only 29% of clients were asymptomatic on all 3 occasions of testing (end of treatment, 3 months and 1 year later) without recourse to further treatment. However, only 11% of those asymptomatic at end of treatment experienced relapse or recurrence of depression, albeit on the limited evidence of just two follow-up assessments. The results of comparisons among treatment conditions at 1 year differed substantially from those obtained earlier: Eight-session PI treatment now appeared less efficacious than the other 3 treatment conditions, and there was now no measurable benefit of 16-session over 8-session CB, irrespective of initial severity of depression. These findings confirm the importance of follow-up in evaluation of psychotherapies for depression.