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New research suggests the placebo effect may be responsible for the benefits of microdosing. microgen/Getty Images
  • Taking microdoses of psychedelic drugs for their possible mental health benefits has been growing in popularity.
  • Research investigating the medical value of microdosing has been inconclusive.
  • Now, researchers at Imperial College London (ICL) in the United Kingdom have introduced a novel control mechanism into such investigations.
  • The ICL researchers identified a strong placebo effect in the perceived benefits of psychedelic microdosing.

Although psychedelic substances remain illegal in most places, a number of people have been microdosing with them in the hopes of achieving psychiatric benefits. These doses are too small — under 10% of a standard dose two or three times per week — to achieve perceptible psychedelic effects.

Early research has been ambiguous regarding the medical value of microdosing. One international survey found that 44% of participants self-reported improvements in their mental health. Another saw no definitive effect but suggested a possible role for microdosing in people experiencing mental health problems.

Now, a new study from ICL researchers suggests a placebo effect is behind the confusion.

Lead author Dr. Balázs Szigeti says, “Anecdotal reports about the benefits of microdosing are almost certainly biased by the placebo effect.”

The study appears in the journal eLife.

Since studies of psychedelic microdosing rely so heavily on self-reporting, previous researchers have had to draw conclusions without the benefit of having a control group to check for placebo effects.

The researchers at ICL worked out a mechanism designed to overcome this study limitation.

The study was conducted online with 191 individuals who were already microdosing psychedelics for their mental well-being.

Researchers guided participants through a procedure where they mixed their psychedelics with identical-looking placebo capsules. The study authors refer to this arrangement as “self-blinding.”

Having mixed the capsules, individuals in the study could not tell whether they were ingesting a psychedelic or a placebo.

The researchers, however, could tell, since each capsule was barcoded so that scanning revealed to them whether it was a placebo or psychedelic.

Consuming capsules over a 4-week period, the participants reported their experiences to the researchers. They were also given online cognitive tasks at various timepoints.

“We have mixed results,” says Dr. Szigeti. He adds:

“On the one hand, we observed microdosing’s benefits in a wide range of psychological measures. On the other hand, we saw equal benefits among participants taking placebos.”

“These findings suggest that the benefits are not due to the drug, but rather due to the placebo-like expectation effects. Many participants who reported that they experienced positive effects while taking the placebo were shocked to learn after the study that they hadn’t been taking the real drug.”

– Lead author Dr. Balázs Szigeti

One benefit of the authors’ methodology is that it captures “real-life” microdosing as the researchers left participants in charge of their own medication schedules.

The scientists caution that insights from online, self-reporting research may ultimately be less reliable than those of a traditional study, even with the self-blinding mechanism employed.

In addition, the authors note that controlling the potency of individuals’ psychedelic substances was impossible since the participants purchased them illegally from black-market sources.

The self-blinding method developed for this study may prove useful — and economically attractive — in other areas of research that rely heavily on self-reporting, according to the senior author of the study, Dr. David Erritzoe.

He says:

“Accounting for the placebo effect is important when assessing trends, such as the use of cannabidiol oils, fad diets, or supplements, where social pressure or users’ expectations can lead to a strong placebo response. Researchers can use self-blinding citizen science initiatives as an inexpensive, initial screening tool before launching expensive clinical studies.”