The Powerful Placebo: From Ancient Priest to Modern Physician

Before the introduction of the double-blind randomized controlled trial (RCT), medicine defined acceptable therapy in terms of therapeutic results. After World War II, with the gradual adoption of the masked RCT methodology as the “gold standard,” medicine redefined legitimacy as an intervention more effective than a placebo. Arthur and Elaine Shapiro’s history of the placebo and the apparatus needed to separate it from “specific” effects is a “positivist” account of medical history from the perspective of this triumphal shift in scientific and moral standards. It is also an example of what some philosophers of science have described as history becoming a reconfiguration of the past to justify research programs.

For the Shapiros, medical history is easily bifurcated into pre- and post-blind RCT. The first part of the book is about medicine under “the hegemony of the placebo” (p. 229). They argue that, with extremely few exceptions, health care before the RCT was placebo therapy. The medicine of the premodern era is exemplified by such examples as crocodile dung and bezoar stone. Their argument has flaws. “Selection bias” is obvious, and theirillustrations are analogous to saying that antibiotics for viral infections or routine electronic fetal monitoring are representative samples of biomedical treatment. The Shapiros neglect the less dramatic elements of traditional materiae medicae containing plants that often have pharmacological properties with physiological effects that may or may not be clinically effective. Somehow, the Shapiros do not need the methodological safeguards they consider so essential in evaluating efficacy when they examine the premodern era. A dismal early past is more fitting for their story line of dramatic rescue. Another problem is that much of the discussion is too simple, ignoring the fact that the placebo effect is relative; it is determined by a comparison between a tested drug and an identical decoy. For example, crocodile dung in some contexts could have absolute effects greater than those of a sugar pill or even of some modern “proven” drugs.

The second major section of the book concerns the development of controlled trials and blind assessment. On controlled trials, the authors have little to say that is new. On blind assessment, they make important contributions beyond anything that has appeared in previous accounts. The Shapiros name R. H. R Rivers (1864–1922) as the first person to have adopted placebo controls in an experiment (1908), and then trace his possible influence to early and neglected researchers such as Hollingwood and Sollmann. The book also has an excellent and sorely needed discussion of Harry Gold (1899–1973) and his colleagues and their pioneering efforts at blind assessment. Much of this material is based on refreshing interviews that provide significant historical insights.

In the preface, Arthur Shapiro (the principal author) apologizes that it was “impossible to satisfy [his] obsessive desire to confirm every detail” (p. x). This remark is an important qualification, because this history is seriously flawed by easily avoidable errors. For example, even in the important blind assessment chapter, the Shapiros fail to note that Rivers provided a lengthy background discussion of German predecessors who had inspired his adoption of sham controls, and thus they do not follow up the obvious lead. Many other examples of insufficient attention to cited material, and even blatant misquotations, are found throughout the text.

Historiography often transgresses into hagiography in this volume. Villains and heroes fit the stereotypical mold whether or not they are guilty of the crimes accused. William Osler and Oliver Wendell Homes are virtuous, despite being aware of the blind assessment method and rejecting its application for orthodox therapies. Unorthodox healers remain quacks, despite having more of an inclination to consider the value of blind assessment. The book becomes much more engaging when it departs from history and deals with secondary themes that reflect Arthur Shapiro’s background as a researcher and psychiatrist. The chapter on whether psychotherapy is more than a placebo is well nuanced. The chapter on why...