Mesmer, the placebo effect, and the efficacy paradox: lessons for evidence based medicine and complementary and alternative medicine

Abstract

Drawing on Isabelle Stengers’ discussion of the investigation of Mesmer and the starring role that experimentation plays in the rationality of modern medicine, this paper examines longstanding tensions between the realms of evidence based medicine and complementary and alternative medicine. While evidence based medicine often claims the ability to demarcate between pseudoscience and science, and complementary and alternative medicine often claims that evidence based medicine involves a kind of pseudo-logic that is unable to capture all forms of efficacy, I argue that both of these claims are unfounded. Unpacking the similarities between the commission that evaluated Mesmer’s magnetism and the structure of evidence based medicine, a significant gap is revealed in today’s system of knowledge production within medicine. In order to demonstrate the efficacy of a novel treatment within a randomized controlled trial, the treatment must be shown to improve clinical outcomes significantly more than a placebo control. However, some treatments improve clinical outcomes, but operate primarily through placebo responses, leading to effective medicines being labelled ‘ineffective’ within randomized controlled trials. This phenomenon is known as the efficacy paradox and appears most frequently in chronic conditions and in relation to complementary and alternative medicine, in which placebo responses are common. It is argued that the realms of evidence based medicine and complementary and alternative medicine have much to learn from each other, in that one has neglected the vast potential of producing clinical benefit through placebo responses, while the other has neglected the understanding that can be gained through experimentation.