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National Conference Explores the Placebo Effect

By Linda Engel and Joan Wilentz

The Jan. 9, 2000, cover story in the New York Times Magazine exclaimed, "Astonishing Medical Fact: Placebos Work! So Why Not Use Them as Medicine?" When prominent national newspapers and health consumers alike are asking doctors to add sugar pills to their treatments, something medically significant appears to be on the horizon.

To explore the basis for and potential applications of the placebo effect and determine future research opportunities, the National Center for Complementary and Alternative Medicine teamed with the National Institute of Diabetes and Digestive and Kidney Diseases to organize a trans-NIH/DHHS workshop, along with 17 other components of NIH and two DHHS groups. More than 500 researchers and research administrators attended the "Science of the Placebo: Toward an Interdisciplinary Research Agenda," held recently at NIH.

NCCAM director Dr. Stephen Straus and NIDDK's Josephine Briggs, event coplanner

"There are numerous aspects to tackle as regards to the cultural, social and genetic factors associated with placebo effects, what induces them, how long they persist, what biological mechanisms might underlie them, whether there are biomarkers to monitor their presence, ethical issues that affect studies of the placebo, optimal clinical study designs to account for their confounding effects," according to NCCAM director Dr. Stephen E. Straus. "Certainly, the placebo effect has major implications for the conduct of all clinical trials."

What Is the Placebo Effect?

The placebo effect may be defined as "desirable physiological or psychological effects attributable to the use of inert medications." Indeed, the potential use of placebos to benefit health and well-being and their continued use in clinical trials are stirring considerable interest and controversy. The placebo effect in itself has become the focus of scientific interest: Can science explain why placebos often work?

Cochaired by Harry Guess, vice-president, epidemiology, Merck Research Laboratories and Dr. Arthur Kleinman, professor of social anthropology and medical anthropology at Harvard, the workshop brought together a multidisciplinary group of experts whose strengths clearly complemented each other. As Guess noted, "the fact that clinical trialists on the one hand and social, behavioral, and biological researchers on the other enlarged each others' perspectives is a noteworthy accomplishment of the meeting and an important first step toward developing an interdisciplinary research agenda to move the field forward." The meeting also highlighted the evolving status of the placebo, from negative perceptions — a sham in clinical care and unwanted statistical noise in clinical trials — to a positive one that appreciates the potential for therapeutic value. "It's clear from the placebo effect that people have the resources inside to get better," offered Dr. Richard H. Gracely, chief of the clinical measurement and mechanisms unit with NIDCR's Pain and Neurosensory Mechanisms Branch.

History of the Field

In plenary sessions of the workshop, researchers summarized the history of the field and provided perspectives on the meaning and mechanisms of the placebo effect from varied points of view: social/cultural, behavioral, biological and ethical. Other speakers addressed the use of placebos in randomized clinical trials and what alternatives to placebos might be used. Videotapes of the plenary sessions may be viewed on the NIH videocast site at

Panelists Anne Harrington and Ted Kaptchuk attend to the proceedings.

Presenters reflected that prior to the 1950's, clinicians had few effective treatments for disease. Medicine was an art that depended on provider-patient interactions, which often incorporated the use of drugs or other measures that today would be considered inert or even harmful. Nevertheless, patients frequently felt better and objectively may have shown improvements in health.

In that light, workshop participants considered whether the notion of placebos should encompass the process — what happens in the course of the patient-provider encounter — or whether placebos should be defined in terms of their effects, as seen in the eyes of the responder as well as in measures of brain and body changes.

Lingering Ethical Questions

Discussions of the ethical use of placebos, both in the clinical setting and in clinical trials, threaded throughout the conference. Recent revisions to the Declaration of Helsinki, a statement developed by the World Medical Association to guide researchers in studies that involve humans, led to profound ethical debates among participants. According to the revision, researchers have a moral responsibility to use the "best current" drugs in trials, and placebos should be used only when no proven treatment exists. While no one disagrees that all patients should receive treatment in cases in which the absence of treatment could cause them harm — for example, in testing new chemotherapeutic agents for cancer — there was disagreement among participants regarding the necessity to provide patients with the "best current" treatment for milder conditions such as allergic rhinitis. In such cases, patients may only experience some discomfort and some argue that their willingness to participate as volunteers with full informed consent should be honored. How individuals resolve the conflict between the worthy principles of guarding the rights of the individual on the one hand, and benefiting society on the other depends on their philosophical leanings.

Summing up the conference, Kleinman said, "Throughout all of this, it is important to consider the findings and what they tell us about a phenomenon that goes to the very heart of what medicine is about. The data are extraordinarily interesting, somewhat controversial, and sometimes not entirely clear. The real issue is to build a future research agenda that is prioritized to those things we can learn the most about and carry it across to research, education and practice." The work now falls to NIH and agencies within DHHS to address the research opportunities identified at the meeting.

A summary of conference proceedings will be submitted to a journal that has agreed to submit it for peer review. Background papers and recommendations will be published in a book by the British Medical Association in early 2002.

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