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Placebo Effect in Psychedelic Drug Studies May Be Stronger Than Once Believed

While there has been a lot of recent interest in using psychedelic drugs to treat depression, a new study suggests that — in the right context — some people may experience psychedelic-like effects from placebos alone.

In the new study, researchers at McGill University in Montreal, Quebec, Canada, reported some of the strongest placebo effects on consciousness in the scientific literature relating to psychedelic drugs. In fact, researchers note that 61 percent of the participants in their experiment reported some effect after taking the placebo.

“The study reinforces the power of context in psychedelic settings. With the recent re-emergence of psychedelic therapy for disorders such as depression and anxiety, clinicians may be able to leverage these contextual factors to obtain similar therapeutic experiences from lower doses, which would further improve the safety of the drugs,” said Jay Olson, a Ph.D. candidate in McGill’s Department of Psychiatry and the lead author on the research paper.

The study participants, who were expecting to take part in a study of the effects of drugs on creativity, spent four hours together in a room that had been set up to resemble a psychedelic party, with paintings, colored lights, and a DJ. To make the context seem credible and hide the deception, the study also involved 10 research assistants in white lab coats, psychiatrists, and a security guard, the researchers described.

The 33 participants had been told they were being given a drug that resembled the active ingredient in psychedelic mushrooms. They also were told they would experience changes in consciousness over the four-hour period.

In reality, everyone consumed a placebo, according to the researchers.

Among the participants were several actors who had been trained to slowly act out the effects of the supposed drug. The researchers said they thought this would help convince the participants that everyone had taken a psychedelic drug, which might lead them to experience placebo effects.

When asked near the end of the study, the majority of the participants — 61 percent — reported some effect of the drug, ranging from mild changes to effects resembling taking a moderate or high dose of an actual drug.

The researchers report there was considerable variation among the participants. For example, several participants stated that they saw the paintings on the walls “move” or “reshape” themselves. Others described themselves as feeling “heavy… as if gravity had a stronger hold,” and one had a “come down” before another “wave” hit her. Several participants told the researchers they were certain they had taken a psychedelic drug.

“These results may help explain ‘contact highs’ in which people experience the effects of a drug simply by being around others who have consumed it,” said Dr. Samuel Veissière, a cognitive anthropologist who teaches in McGill’s Department of Psychiatry and supervised the study. “More generally, our study helps shed light on the ‘placebo boosting’ component inherent in all medical and therapeutic intervention, and the social influences that modulate these enhancing effects.

“Placebo effects may have been underestimated in psychedelic studies. The current trend towards ‘micro-dosing,’ consuming tiny amounts of psychedelic drugs to improve creativity, for example, may have a strong placebo component due to widespread cultural expectations that frame the response.”

The study was published in the journal Psychopharmacology.

Source: McGill University

Placebo Effect in Psychedelic Drug Studies May Be Stronger Than Once Believed

Janice Wood

Janice Wood is a long-time writer and editor who began working at a daily newspaper before graduating from college. She has worked at a variety of newspapers, magazines and websites, covering everything from aviation to finance to healthcare.

APA Reference
Wood, J. (2020). Placebo Effect in Psychedelic Drug Studies May Be Stronger Than Once Believed. Psych Central. Retrieved on November 30, 2020, from
Scientifically Reviewed
Last updated: 4 Apr 2020 (Originally: 4 Apr 2020)
Last reviewed: By a member of our scientific advisory board on 4 Apr 2020
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