Psilocybin microdosing does not affect emotion-related symptoms and processing: A preregistered field and lab-based study.
Level 2 - randomized trial
Preregistered double-blind, placebo-controlled, within-subject crossover trial
PubMed 34915762 · doi:10.1177/02698811211050556
What was done
In a preregistered, double-blind, placebo-controlled, within-subject crossover trial, participants self-administered psilocybin microdoses or placebo over 3 weeks. Participants completed the Multidimensional Assessment of Interoceptive Awareness Questionnaire 1.5 hours after their second dose (or placebo), and both an emotional go/no-go task and the shortened Depression Anxiety Stress Scale 1.5 hours after their seventh dose.
What was found
The abstract reports no numerical values. Confirmatory analyses revealed that psilocybin microdosing did not affect emotion processing or symptoms of anxiety and depression compared with placebo. Exploratory analyses showed no effect on self-reported interoceptive awareness or expectations, though depression and stress symptoms decreased in the first block compared with baseline, and participants broke blind in the second block.
Why it matters
This study provides controlled experimental evidence challenging widespread anecdotal claims that sub-hallucinogenic psilocybin microdosing improves mood and emotional processing.
Limits
The abstract does not state the sample size, dose amounts, or baseline participant characteristics. Blinding was compromised in the second block, and the study was not conducted in a substance-naive population with clinical-range depression or anxiety.