Microevidence for microdosing with psilocybin mushrooms: a double-blind placebo-controlled study of subjective effects, behavior, creativity, perception, cognition, and brain activity
In a double‑blind placebo‑controlled study of 34 individuals who planned to microdose with 0.5 g dried Psilocybe cubensis, acute subjective effects were stronger with active doses (likely due to unblinding) but most objective measures showed no benefits and instead a trend toward cognitive impairment and reduced EEG theta power. The results suggest that expectation/placebo effects may account for many of the anecdotal benefits attributed to psilocybin microdosing.
Authors
- Enzo Tagliazucchi
- Claudio Pallavicini
- Michal Kuchar
Published
Abstract
The use of low sub-hallucinogenic doses of psychedelics (“microdosing”) has gained popularity in recent years. Although anecdotal reports claim multiple benefits associated with this practice, the lack of placebo-controlled studies limits our knowledge of microdosing and its effects. Moreover, research conducted in laboratory settings might fail to capture the motivation of individuals engaged in microdosing protocols. We recruited 34 individuals planning to microdose with psilocybin mushrooms ( Psilocybe cubensis ), one of the materials most frequently used for this purpose. Following a double-blind placebo-controlled design, we investigated the effects of 0.5 g dried mushrooms on subjective experience, behavior, creativity, perception, cognition, and brain activity. The reported acute effects were significantly more intense for the active dose compared to the placebo, which could be explained by unblinding. For the other measurements, we observed either null effects or a trend towards cognitive impairment and, in the case of EEG, towards reduced theta band spectral power. Our findings support the possibility that expectation effects underlie at least some of the anecdotal benefits attributed to microdosing with psilocybin mushrooms.
Research Summary of 'Microevidence for microdosing with psilocybin mushrooms: a double-blind placebo-controlled study of subjective effects, behavior, creativity, perception, cognition, and brain activity'
Introduction
Over the last decade, microdosing—taking sub-hallucinogenic amounts of psychedelics—has become a widely reported practice, with users claiming improvements in mood, cognition, creativity and relief from certain clinical symptoms. However, much of the evidence supporting these claims comes from self-selected, uncontrolled surveys and open-label studies, leaving the field vulnerable to expectancy effects, confirmation bias and variability in dosing schedules and materials. Prior controlled work on low doses of psychedelics (mostly LSD and some psilocybin) has produced mixed findings and has highlighted the importance of maintaining blinding and measuring physiological and neurobiological endpoints in addition to self-report. Cavanna and colleagues set out to test acute effects of a standardised microdose of Psilocybe cubensis in a pragmatic, double-blind, placebo-controlled design that preserved ecological validity. They recruited people already planning to begin a microdosing protocol with their own mushroom material, randomised each participant to one week of active capsules and one week of placebo capsules (order counterbalanced and blinded), and assessed subjective experience, behaviour, creativity, perception, cognition, physical activity and resting-state EEG. The study aimed to determine whether a 0.5 g dried mushroom dose (taken twice in a week) would produce measurable effects beyond placebo while controlling for unblinding and expectation.
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Study Details
- Study Typeindividual
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- APA Citation
Cavanna, F., Muller, S., de la Fuente, L. A., Zamberlan, F., Palmucci, M., Janeckova, L., Kuchar, M., Pallavicini, C., & Tagliazucchi, E. (2021). Microevidence for microdosing with psilocybin mushrooms: a double-blind placebo-controlled study of subjective effects, behavior, creativity, perception, cognition, and brain activity. https://doi.org/10.1101/2021.11.30.470657
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