Mediators and Mechanisms of Psychotherapy: Evaluating Criteria for Causality

Abstract

Although the efficacy of psychotherapy for treating many disorders has been demonstrated in randomized clinical trials (Ekers, Richards, & Gilbody, 2008; Hofman & Smits, 2008; Hoglend, 1999), little is known about the mechanisms through which psychotherapy achieves its effects (Kazdin, 2005). The purpose of this review is to examine the state of research on the mechanisms of psychotherapy. First, a definition of mechanism is presented and the importance of studying mechanisms in psychotherapy is discussed. Then, methods of demonstrating mediation in empirical studies are reviewed along with selected areas of empirical research on mechanisms of cognitive therapy. Finally, suggestions for future directions in studying mechanisms are offered.