Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 35918311 · doi:10.1038/s41398-022-02039-0
What was done
Thirty-four individuals starting a psilocybin mushroom (Psilocybe cubensis) microdosing regimen were recruited for a double-blind, placebo-controlled experimental study. Researchers assessed the acute and short-term effects of 0.5 g of dried mushrooms versus placebo on subjective experience, behavior, creativity (divergent and convergent thinking), perception, cognition, and electroencephalographic (EEG) brain activity.
What was found
The abstract reports no numerical values. Subjective acute effects were significantly more intense following the active dose compared to placebo, but this difference occurred only among participants who correctly identified their experimental condition. Active dosing reduced EEG power in the theta band while preserving Lempel-Ziv broadband signal complexity. For all other measures, microdosing had no effect aside from a few small changes indicating cognitive impairment, with no observed enhancements in well-being, creativity, or cognitive function.
Why it matters
This study provides rigorous placebo-controlled evidence that anecdotal cognitive and mood benefits from psilocybin microdosing are likely driven by expectancy and unblinding rather than pharmacological enhancement.
Limits
The sample size was small (n = 34) and limited to self-selected individuals initiating microdosing. Blinding integrity was compromised as subjective differences were tied to correct condition guessing. The abstract does not report exact numerical metrics, confidence intervals, or specific measures of the observed cognitive impairments.
Cited by
- partial There is zero scientific evidence that microdosing psilocybin provides any clinical or cognitive benefit.