Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing.
Level 4 - case-series / case-control
Prospective, uncontrolled observational survey study
PubMed 33479342 · doi:10.1038/s41598-021-81446-7
What was done
A prospective web-based survey tracked individuals planning a weekly psychedelic microdosing regimen. Participants completed surveys before, during, and after a four-week test period to assess mental health outcomes and baseline expectancy. Eighty-one participants completed the primary study endpoint.
What was found
No numerical values or effect sizes are reported in the abstract. The abstract states that at the four-week primary endpoint, participants showed increased self-reported psychological well-being, emotional stability, psychological resilience, social connectedness, agreeableness, nature relatedness, and aspects of psychological flexibility, as well as reductions in state anxiety and depressive symptoms. Positive expectancy scores at baseline significantly predicted subsequent improvements in well-being.
Why it matters
The findings indicate that psychological benefits observed in naturalistic psychedelic microdosing are largely driven by pre-existing positive expectations, highlighting the major influence of placebo response.
Limits
The study lacked a randomized control or placebo group, relied entirely on self-selected participants and self-report web surveys, and had a modest sample size (n = 81). Dosing, substance identity, and purity were uncontrolled and unverified.
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