Science of the Placebo: Toward an Interdisciplinary Research Agenda.

OVERVIEW

Do placebos work? For many conditions, you bet they do! Maybe in some people most of the time; maybe even in all people some of the time. Those are among the conclusions that experts drew from a comprehensive review of placebo effects that took place at the National Institutes of Health. The meeting, designed to bring basic biomedical and behavioral scientists together with clinicians and clinical trial experts, developed an expanded concept of the placebo, explored a variety of explanatory mechanisms of why placebos word when they work, and discussed the pros and cons of using placebos in clinical trials. The experts went on to develop a research agenda to further progress in the field.]

The result is a new look at placebos, one that calls for careful consideration of the complex ethical issues incolved in exploiting placebo effects, but sees their potential as therapeutic allies in clinical practice.

The chapters serve as an essential practical and theoretical guide to practitioners, researchers, bioethicists, patients, and students who want a comprehensive review of the state of placebo science and placebo controlled clinical trials. They include:

• The historical context and ethical perspectives;
• Explanatory psychosocial and physiological mechanisms (for example, social and cultural meanings, classic conditioning, social learning, intervening psychophysiology)
• The need to distinguish placebo effects from biological and statistical artifacts
• Issues concerning the use of placebo groups in clinical trials: ethics, metholological issues, pros, cons, and alternatives
• Priorities for future research

The publication of this book has important implications for clinical medicine, making it essential reading for clinical researchers, basic scientis and health care practitioners.

TABLE OF CONTENTS

In the introductory chapter the delegates of the conference express their experiences with the placebo and its effect and point out that many of these experiences differ from what Hrobjartsson and Gotzsche found in their analysis. The main fallacies regarding the interpretation of the placebo being discussed are, for example, that a placebo is often mistaken for a sham and that some researchers still see the placebo effect as ‘noise’ in a randomised controlled trial. Moerman brings forward his idea of the ‘meaning response’: in a patient–practitioner interaction the meaning response consists of language, procedures, settings and the processing of information.

Various explanations for the psychosocial mechanism of the placebo effect have previously been suggested, such as personality factors, therapeutic relationship, expectations, hope and classical conditioning. However, scientists all over the world still argue whether it is more important to test the efficacy of the placebo effect or its mechanism of action.

In the next chapter, a historical perspective is being taken to lead the reader through the changes in attitudes and perceptions of the placebo effect over the last decades. It is observed that not everyone sees the placebo effect as (in theory) functioning as a therapy.

Chapter 3 discusses ethical issues of the placebo effect and weighs the benefits for individual patients from placebo use against possible risks for patients, health professionals and society as a whole.

In Chapter 4 the meaning response as consisting of physiological and/or psychological effects of meaning in the treatment of illnesses is discussed in more detail and Chapter 5 seeks explanations for mechanisms, such as cognition, personality and social learning.

Regression to the mean is explained in Chapter 7 and it is suggested that it likely explains much of what has been described as the placebo effect but that it cannot explain all of the reported placebo effects.

Further to previous discussions, in Chapters 8 and 9 it is argued that the placebo effect represents a phenomenon linking belief to well-being that can be analysed systematically to prove insights into how beliefs might affect immune responses and disease expression or severity.

The second part of the book – Chapters 10–14 – provide a discussion of the use of placebos in clinical trials and the pros and cons of equivalence trials.

Finally, in Chapter 15, priorities for future research and different research ideas that need to be further developed by healthcare professionals are discussed.

To summarise the content of the book, some of the aspects of the placebo and the placebo effect are admittedly being repeated throughout the chapters. However, the book gives the reader a valuable insight into the process of developing ideas about the phenomena collected by researchers with various medical backgrounds.