Predicting the outcome of psychotherapy. findings of the Penn Psychotherapy Project

Our study of predictability of outcomes of psychotherapy used predictions of two kinds: (1) direct predictions by patients, therapists, and clinical observers; and (2) predictive measures derived from the same sources. Seventy-three nonpsychotic patients were treated in psychoanalytically oriented psychotherapy (mean, 44 sessions). Two thirds of the therapists were residents in psychiatry; one third were more experienced. The two main composite outcome measures, measured at termination, were Raw Gain (residualized) and Rated Benefits, which intercorrelated at .76. Most patients improved and showed a considerable range of benefits. The clinical observers' direct predictions of Rated Benefits were highest (.27, P less than 905). The success of the predictive measures were generally insignificant, and the best of them were in the .2 to .3 range meaning that only 5% to 10% of the outcome variance was predicted. The Prognostic Index Interview variables did the best (eg, emotional freedom composite, .30; a crossvalidation for 30 patients was .39 (P less than .05). Neither the therapist measures nor the early psychotherapy session measures predicted significantly. Reanalysis of the similar Chicago Counseling Center study, in our terms, showed a similar low level of prediction success, eg, adequacy of functioning, marital status match, and length of treatment predicted significantly in both studies.