A tale of two therapies: psychotherapy and complementary and alternative medicine (CAM) and the human effect.

Meta-analyses show that psychotherapy and complementary and alternative medicine (CAM) are effective primarily or entirely due to contextual factors rather than the specific disease-treating factors suggested by the therapy. Therapists are the most important contextual factor. Psychotherapy research shows that therapist effectiveness varies from zero to about 80%, but has failed to identify what makes a good (ie charismatic) therapist. Therapist effects are unrelated to experience or training or type of therapy. The conclusion that CAM and psychotherapy are effective due to the human effect leads to more questions than it answers. We do not know what charismatic therapists communicate to patients, we do not know the mechanism of communication, and we do not know how this communication influences the patient therapeutically. The therapist matters, but how or why we do not know. We need a better understanding of therapist effects, in psychotherapy, in CAM and also amongst physicians.