Jan 23

Placebos are part of human history
Placebos have a long and important history in human therapies. From ancient times to now, placebos have been widely used. Although their usage is now mostly intended to be used in clinical research, placebos have frequently been unintentionally used. Hence, for centuries, non effective therapies (placebos) were often used when no other adequate treatment was available. Because of their such positive psychological effects, those placebos are thought to have offered some means of relieving pain and even reversed the disease processes. As a matter of fact, “Placebo” comes from a Latin root meaning “I shall be pleasing or acceptable”.

1930: Placebos use in Clinical Trials
The expression “placebo”, as we often know today, was first used by Sollmann, in 1930. Placebo now referred to a control in studies and was linked to a “blind test”. Although the formal placebo-controlled study occurred in 1931, it wasn’t until the double blind randomized controlled clinical research developed, in the years following World War II, that it became of common use in clinical trials. Placebos were considered a morally acceptable and a harmless research contrasting tool, without the therapeutic actions or the side effects.

1950: The Placebo effect in Clinical Trials
However, in the mid-century, as the double blind randomized controlled took form, scientists started speculating about the powerful therapeutic effects of placebos, therefore questioning its use in clinical and research settings. Placebos were investigated and the outcome of the studies showed that subjects responded positively to placebos (Breecher et al., 1955), leading to the beginning of a medical and scientific controversy over placebo use in clinical research.

1960: The debate over Placebos use in Clinical Trials and the Declaration of Helsinki
With a new debate on the ethics of clinical research in the 1960’s, people became more aware of controversial research practices that had taking place over the past decades. In the heart of the debate, the World Medical Association published its Declaration of Helsinki: Ethical Principles for Medical Research Involving Human Subjects in 1964. The Declaration stated that when research is conducted in the context of clinical care:

“In any medical study, every patient – including those of a control group, if any – should be assured of the best proven diagnostic and therapeutic method.”

The Declaration of Helsinki brought even more confusion about the use of placebos in medical research. While some suggested that the statement was prohibiting new research since “unproven” therapies could not be tested, others understood otherwise. They believed that the aim of the statement was to supplement an effective therapy to patients seeking care, such as those enrolled in clinical trials.

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1990: The debate over Placebos use in Clinical Trials and the ICH
As ethics was becoming a critical part of research, there was an increase in the quantity of regulations surrounding all aspects of new medical products (e.g. drugs, medical devices). In the 1980`s, the European Commission (now the European Union) took the first steps towards harmonization. Japan and the U.S. quickly followed. The 1990`s saw the birth of the International Conference on Harmonisation (ICH). This group, including regulatory authorities and industry representatives from the U.S., Japan and Europe, established the documents that currently act as guidelines for many countries regulators. The ICH-E10 Guideline allows placebo controls except in cases where there is proven treatment that is “life-saving or known to prevent irreversible morbidity”.


(1) Anne Harrington, The Placebo Effect: An Interdisciplinary Exploration, Harvard University Press, 1999

(2) Health Canada

(3) U.S. Food and Drug Administration (FDA)

(4) International Conference on Harmonisation (ICH)

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