• Applicants for outpatient psychotherapy completed a symptom checklist that permitted evaluation of the duration, intensity, and patterning of presenting symptoms. Random assignment of patients acceptable for psychotherapy to immediate treatment or to the waiting list resulted in two comparable groups who repeated the symptom checklist after an average interval of nine months.
Patients in psychotherapy showed a greater reduction in average intensity of all symptoms than was observable in the waiting list group. In the waiting list group, improvements tended to be limited to those patients whose conditions were of comparatively brief duration. In the psychotherapy group, improvements of chronic patients were frequent; however, improvements tended to occur among those patients reporting some new symptoms rather than those giving no evidence of exacerbation. A predominance of "neurotic" over "behavioral" complaints also appeared to be predictive of a positive response to psychotherapy.
Siegel SM, Rootes MD, Traub A. Symptom Change and Prognosis in Clinic Psychotherapy. Arch Gen Psychiatry. 1977;34(3):321-329. doi:10.1001/archpsyc.1977.01770150079009