-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.
KEY WORDS: CAM, common factors, complementary and alternative medicine, context, efficacy, meta-analysis, psychotherapy, therapist effectsPsychotherapy and complementary and alternative medicine (CAM) are both popular but controversial therapies and both involve quality therapist-patient contact. The increasing popularity of CAM 1 is matched by a reduction in the use of psychotherapy. 2 Research into psychotherapy is better established: there are about five times as many psychotherapy publications as there are on CAM (Box 1). This paper uses meta-analyses to: (a) draw attention to similarities in the 'research stories' of these two therapies, and (b) come to some conclusions about the human effect in therapy.
The psychotherapy research storyIn any psychotherapy, two types of factor can have a therapeutic effect: specific factors and incidental (or non-specific) factors. The specific factors are specific to a particular psychotherapy, they correct the assumed underlying pathology, and are commonly assumed to be the major contributor to therapeutic outcome. For example, in cognitive behavioural therapy (CBT), the underlying pathology is assumed to be erroneous cognitions, and the specific factors are the therapist-patient interactions that correct those erroneous cognitions. The incidental factors are factors that are incidental to the process of delivering the specific factors. They include emotional contact with the patient, a shared interpretation of the problem, and expectancy of a positive outcome. Because the incidental aspects are common across all psychotherapies, they are also known as common factors.The majority of research in psychotherapy is designed to demonstrate the superiority of one set of specific factors over another or in contrast to the common factors. Many studies demonstrate superiority. However, efficacy research in psychotherapy is confounded by the researcher's allegiance to a therapy (and consequently the therapist's allegiance), and allegiance correlates with outcome. When allegiance is taken into a...