An intensive empirical methodology is introduced to evaluate the efficacy of Cognitive Behavioral Analysis System of Psychotherapy (CBASP) treatment for outpatients with early onset chronic depression. The patient with chronic illness presents a unique measurement challenge to psychotherapists. One of the most prominent reasons is the refractory nature of the disorder. In order to measure the change process, the authors have found it helpful to use an acquisition-learning methodology to answer three questions: (1) What are we trying to teach the patient? (2) How much has the patient learned throughout the course of therapy? And, (3) how does the extent of patient learning impact the change indices at the end of treatment and during the follow-up period? Answering questions 2 and 3 allows us to superimpose the change process variables over the performance learning variables on a graph. These combined variables also allow us to test the hypothesis: By learning what psychotherapy teaches, the chronic psychological disorder may be resolved.