Explaining change in psychotherapy : an examination and comparison of the theories of change in cognitive therapy and psychoanalytic self psychology

Psychotherapy works. But it is less clear how. Most models of therapeutic change are wedded to specific therapeutic interventions, offering theoretical explanations for a technique-outcome link. However, these links have not, so far, stood up to empirical investigation, and the weight of evidence suggests common rather than specific factors account for therapeutic change. Notwithstanding the evidence, there is a poverty of theory to explain why, how, or even which common factors are therapeutic. This thesis argues that the absence of such theory has impeded research into how psychotherapy works and may thereby have impeded the development of more- effective psychotherapy. The present study sought to address this problem by revisiting two quite different but well-established specific factor theories of therapeutic change. It investigated their explanatory power with respect to the more recent findings concerning common therapeutic factors and treatment outcome. The theories chosen were Self Psychology and Cognitive Therapy. A Logic Model of each theory was generated, mapping the explicit and implicit mechanisms of change. The two models were then subjected to rigorous theoretical scrutiny in two phases. First, a goodness of fit approach was used to evaluate their capacity to explain the common factors findings. Second, the theoretical integrity of the models was tested against criteria derived from the philosophy of science literature. This included a reciprocal critique of each theory—critique from the vantage point of the other theory. It was found that the Logic Model derived from Self Psychology explained better the common factors findings and was better able to yield testable hypotheses for further research. It was concluded that this model provides a framework for more rigorous investigation of common factors findings