Moving from empirically supported treatment lists to practice guidelines in psychotherapy: the role of the placebo concept.

The use of placebos is the "gold standard" in studies of investigational drugs, and of other medical procedures as well. Several recent trends have suggested the use of placebos in studies of psychotherapy to isolate effective treatment components, and as a basis for establishing lists of empirically supported treatments. Unlike within the domain of medicine, in which the logic of placebos is relatively straightforward, the concept of placebo as applied to psychotherapy is fraught with both conceptual and practical problems. The evidence-based practice of psychotherapy can best be promoted through the development of practice guidelines, for which psychotherapy placebos are unnecessary. Moreover, even if problems associated with psychological placebos could be overcome, they are not necessary in psychotherapy research.