The Nocebo Effect: When Words Make You Sick

An investigation of the nocebo effect—the placebo effect’s evil twin.

Can beliefs make you sick? Consider “The June Bug” incident from a US textile factory in the early 1960s. Many employees began to feel dizzy, had an upset stomach, and vomited. Some were even hospitalized. The illness was attributed to a mysterious bug biting workers. However, when the CDC investigated this outbreak, no bugs or any other cause of the illnesses could be identified. Instead, it appears to be an illness caused by the mind — that is, sickness due to expectation.

The June Bug story is one of many striking examples of the nocebo effect, a phenomenon best summarized as the occurrence of a harmful event that stems from expecting it. The nocebo effect plays a role in side effects for some of the most commonly prescribed medications. It provides a lens for understanding how sensationalized media reports that sound alarm about public health might even become a self-fulfilling prophecy. It might even explain the mysterious symptoms associated with Havana Syndrome, during which dozens of US government employees fell ill after reportedly being exposed to an unidentified sound wave in Cuba.

We are just discovering the power behind this effect and how it can be ethically mitigated. Enlightening and startling, The Nocebo Effect is the first book dedicated to investigating this fascinating phenomenon by the foremost experts in the field.


Charlotte Blease, Ph.D., is a philosopher and interdisciplinary health researcher at Digital Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, and Department of Women’s and Children’s Health, Uppsala University, Sweden. She is a former Fulbright Scholar and a winner in 2012 of the UK-wide BBC Radio 3’s New Generation Thinkers Competition. Dr. Blease has written extensively about the ethics of placebo and nocebo effects. Her research has been profiled by international news outlets including The Washington Post, The Guardian, and The Sydney Morning Herald.

Cosima Locher, Ph.D., is a psychologist and researcher at the Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, University of Zurich, Switzerland. She is dedicated to studying honest (e.g., “open-label”) placebos. She is published in leading peer-reviewed journals, such as PAIN, the American Journal of Psychiatry, JAMA Psychiatry, and JAMA Pediatrics. Dr. Locher is a co-founder of The Pain Net, an international network of researchers interested in Chronic Primary Pain, including with a special focus on the placebo effect

Walter A. Brown, M.D., is a Clinical Professor Emeritus of Psychiatry and Human Behavior at the Warren Alpert Medical School of Brown University. He has studied the placebo effect for the past 40 years, and is the author of three books, including The Placebo Effect in Clinical Practice.

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“In this pioneering book, leading researchers show how words help shape our conscious experience of the world, which in turn directly affects our bodies and our health. The more we know, the more we can say ‘no’ to nocebos.” – John Bargh, Susan Nolen-Hoeksema Professor of Psychology and Cognitive Science, Yale University, and author of Before You Know It: The Unconscious Reasons We Do What We Do

“An excellent and well-written discussion of ‘the pla­cebo effect’s evil twin’ by leading researchers in the field. Reading this book has the potential of decreasing the reader’s experience of nocebo effects, and for that reason, I highly recommend that it be read by everyone.”—Irving Kirsch, Associate Director of the Program in Placebo Studies at the Harvard Medical School and author of The Emperor’s New Drugs

“An outstanding compilation of the latest research by eminent researchers in the field. Written in an understandable way, The Nocebo Effect is a helpful manual for readers to stop “nocebo-ing” themselves.”—Jeremy Howick, Director of the Stoneygate Centre for Empathic Healthcare at the University of Leicester, Director of the Oxford Empathy Program, and author of The Powerful Placebo

“A fascinating multidisciplinary volume that offers a comprehensive understanding of an underappreciated force in medicine and psychology, and provides illuminating insights into improving care.”—Rob Henderson, founding faculty fellow at UATX and author of Troubled: A Memoir of Foster Care, Family, and Social Class

“The nocebo effect has been so far understudied and underestimated compared to the placebo effect. This volume fills that gap by providing an exciting, comprehensive, and interdisciplinary account of a phenomenon that certainly needs more attention.”—Fabrizio Benedetti, M.D., Professor of Neurophysiology, University of Turin Medical School, Turin, Italy

“This book is needed, comprehensive, evidence-based and, most importantly, opens as many discussions as it provides answers. A must-have and must-read for anyone in clinical practice and research.”—Prof. Dr. Jens Gaab, University of Basel, Switzerland