Forstmann · Proceedings of the National Academy of Sciences of the United States of America 2020 · observational field study · n=>1,200

Transformative experience and social connectedness mediate the mood-enhancing effects of psychedelic use in naturalistic settings.

Cited 188 times in the scientific literature.

Level 3 - non-randomized controlled study

Multi-site observational field study with statistical controls (non-randomized cohort/cross-sectional design).

PubMed 31964815 · doi:10.1073/pnas.1918477117 · record verified 2026-08-26

What was done

Researchers conducted preregistered field studies involving over 1,200 participants across six multiday mass gatherings in the United States and the United Kingdom. Participants completed surveys assessing psychedelic use, transformative experiences, social connectedness, positive mood, demographic variables, and concurrent psychoactive substance use. Sequential mediation models were evaluated while adjusting for demographics and other substances.

What was found

Psychedelic use was significantly associated with positive mood, sequentially mediated by self-reported transformative experience and increased social connectedness. Effects were more pronounced among participants reporting psychedelic use within the preceding 24 hours compared with the prior week. The abstract reports no exact numerical values, effect sizes, or test statistics.

Why it matters

This study provides naturalistic, ecologically valid evidence that transformative psychological experiences and social bonding mediate the mood-enhancing effects of psychedelic use in communal settings.

Limits

No exact numbers, effect sizes, or confidence intervals are reported in the abstract. The non-randomized observational design precludes causal inference. Substance intake, dose, and purity were based entirely on unverified self-reports, and attendees of mass gatherings represent a highly self-selected sample.

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