INITIAL SEVERITY AND DIFFERENTIAL TREATMENT OUTCOME IN THE NATIONAL INSTITUTE OF MENTAL-HEALTH TREATMENT OF DEPRESSION COLLABORATIVE RESEARCH-PROGRAM

Random regression models (RRMs) were used to investigate the role of i nitial severity in the outcome of 4 treatments (cognitive-behavior the rapy [CBT], interpersonal psychotherapy [IPT],-imipramine plus clinica l management [IMI-CM], and placebo plus clinical management [PLA-CMI]) for outpatients with major depressive disorder seen in the National I nstitute of Mental Health Treatment of Depression Collaborative Resear ch Program. Initial severity of depression and impairment of functioni ng significantly predicted differential treatment effects. A larger nu mber of differences than previously reported were found among the acti ve treatments for the more severely ill patients; this was due, in lar ge part, to the greater power of the present statistical analyses.