Placebo and Psychotherapy: Differences, Similarities, and Implications.

The placebo and psychotherapy are both effective psychological interventions. Next to being characterized by their own and specific controversies and debates, there is a persistent-and least for psychotherapy-looming notion that these two interventions share more than just the first letter. Based on Grünbaum's influential conceptualization of placebo, this chapter critically reviews both the time-honored claim that psychotherapy is a placebo as well as the argument that the placebo concept does not translate to psychotherapy. We conclude that there is an unwanted proximity between these two interventions and that empirical attempts to separate the "wheat from the chaff" in psychotherapy research face several distinctive challenges and thus are often methodologically comprised by the integrity of the placebo. However, drawing on recent, innovative research, we conclude that psychotherapy can be saved, i.e., shown to be distinct from the placebo, by employing study designs derived from the placebo research. We conclude that the placebo concept has profound implications for psychotherapy, psychotherapy research, and last but not least its ethical practice.