A comparison of dose-response curves in cognitive-behavioral and psychodynamic psychotherapies

Changes in patient‐ and therapist‐rated process items, and patient‐rated symptom severity assessed over a maximum of 30 sessions of psychodynamic or cognitive–behavioral psychotherapy were compared in an outpatient mental‐health clinic. Patients' ratings in psychodynamic psychotherapy on two of the process items were superior to ratings by patients in cognitive–behavioral therapy, and interactions with time were discovered for an interpersonal item. Comparisons between patients who reported their initial symptom severities as most severe and those with less severe symptoms also were made, with results indicating differential effects of treatment according to perceptions of symptom severity. Interactions between length of stay in treatment and number of sessions also were investigated. Findings indicated that patients benefit from psychotherapy over time and support the usefulness of a contextual model for psychotherapy funding. © 2001 John Wiley & Sons, Inc. J Clin Psychol 57: 63–73, 2001.