Cited by 905Psychedelics and Drug StudiesReligion, Spirituality, and PsychologyParanormal Experiences and Beliefs

Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later

Open access
Griffiths, RR, Richards, WA, Johnson, MW, McCann, UD, Jesse, R.·2008·Journal of Psychopharmacology

Abstract

Psilocybin has been used for centuries for religious purposes; however, little is known scientifically about its long-term effects. We previously reported the effects of a double-blind study evaluating the psychological effects of a high psilocybin dose. This report presents the 14-month follow-up and examines the relationship of the follow-up results to data obtained at screening and on drug session days. Participants were 36 hallucinogen-naïve adults reporting regular participation in religious/ spiritual activities. Oral psilocybin (30 mg/70 kg) was administered on one of two or three sessions, with methylphenidate (40 mg/70 kg) administered on the other session(s). During sessions, volunteers were encouraged to close their eyes and direct their attention inward. At the 14-month follow-up, 58% and 67%, respectively, of volunteers rated the psilocybin-occasioned experience as being among the five most personally meaningful and among the five most spiritually significant experiences of their lives; 64% indicated that the experience increased well-being or life satisfaction; 58% met criteria for having had a 'complete' mystical experience. Correlation and regression analyses indicated a central role of the mystical experience assessed on the session day in the high ratings of personal meaning and spiritual significance at follow-up. Of the measures of personality, affect, quality of life and spirituality assessed across the study, only a scale measuring mystical experience showed a difference from screening. When administered under supportive conditions, psilocybin occasioned experiences similar to spontaneously occurring mystical experiences that, at 14-month follow-up, were considered by volunteers to be among the most personally meaningful and spiritually significant of their lives.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1177/0269881108094300

Cites

49 of 49 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Psilocybin is a serotonergic classic psychedelic that has been examined in combination with psychological support as a promising treatment option in clinical trials for various disorders.

    “Psilocybin (4-phosphryloxy-N,N-dimethyltryptamine) is a serotonergic classic psychedelic (19–25) that has been examined in combination with psychological support as a promising treatment option in clinical trials for various disorders (26–28).”

    From Acute and post-dosing effects of single-dose psilocybin for obsessive-compulsive disorder in a randomized, double-blind, placebo-controlled trial: an interpretative phenomenological analysis (2025) · cites this paper as [21]

    The Introduction identifies psilocybin as a classical hallucinogen whose effects are primarily mediated at 5-HT2A receptors, and the Methods describe preparation and interpersonal support. But the Comment proposes re-initiating therapeutic trials; this study followed volunteers’ experiences, not psilocybin treatment trials for various disorders. Its discussion of earlier treatment studies concerns classical hallucinogens generally. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • Psilocybin increases emotional empathy, attachment security and other prosocial effects.

    “supporting evidence that psilocybin increases emotional empathy, attachment security and other prosocial effects, which has been observed previously [61,62].”

    From Psilocybin‐assisted psychotherapy for methamphetamine use disorder: A pilot open‐label safety and feasibility study. (2025) · cites this paper as [62]

    The Results (page not supplied) report higher retrospective ratings of positive social effects and behavior after psilocybin than after methylphenidate; the Comment also describes positive changes in altruism. The paper does not report increases in emotional empathy or attachment security, so those specific parts of the claim are unsupported. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • Psychedelic experiences in clinical settings are often characterized as highly meaningful.

    “Psychedelic experiences in clinical settings are often characterized as highly meaningful.”

    From Authenticity and Love Drugs: Insights from Psychedelic Therapy (2026) · cites this paper as Griffiths et al. 2008

    The Comment section reports that many volunteers rated their psilocybin experience among the most personally meaningful of their lives. The Methods and Comment sections describe a supported, laboratory-based study of healthy volunteers, not psychedelic experiences across clinical settings generally. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Psilocybin treatment has been described as one of the most meaningful experiences in the lives of participants of several studies.

    “psilocybin treatment has been described as one of the most meaningful experiences (Griffiths et al. 2008;Smith and Sisti 2020) in the lives of participants of several studies.”

    From Authenticity and Love Drugs: Insights from Psychedelic Therapy (2026) · cites this paper as Griffiths et al. 2008

    The Results and Comment report that 58% of volunteers rated their psilocybin-session experience among the five most personally meaningful of their lives. This supports the meaningful-experience claim, but the study involved hallucinogen-naïve volunteers in a laboratory session, not patients receiving psilocybin treatment. (LLM, conf=0.85)

    Experimental — accuracy not yet measured
  • In this trial, participants rarely described the full array of acute effects that together prototypically constitute 'full mystical experiences' described in landmark studies.

    “in our trial, participants rarely described the full array of acute effects that together prototypically constitute ‘full mystical experiences’ described in landmark studies (e.g., psilocybin for existential distress or depression) (21, 63).”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 5

  1. James W The Varieties of Religious Experience 1902 New York Penguin Books republished 1958
  2. Metzner R Teonanacatl: sacred mushroom of visions 2004 El Verano, California Four Tree Press
  3. Metzner R Litwin G Weil G The relation of expectation and mood to psilocybin reactions: a questionnaire study Psychedelic Review 1965 5 3 39
  4. Pahnke WN Drugs and mysticism: An analysis of the relationship between psychedelic drugs and the mystical consciousness Thesis presented to the President and Fellows of Harvard University for the Ph.D. in Religion and Society 1963
  5. Pahnke WN DeBold RC Leaf RC LSD and religious experience 1967 Middletown, CT LSD Man & Society. Wesleyan University Press 60 85

Cited by

Sorted by citations

Authors
Griffiths, R., Richards, W., Johnson, M., McCann, U., & Jesse, R.
Affiliations
  • Johns Hopkins University (US)
  • Johns Hopkins Bayview Medical Center (US)
  • Council on Spiritual Practices, San Francisco, CA, USA
Corresponding author
Griffiths, RR
Venue
Journal of Psychopharmacology
Published
2008-05-30
Volume
22
Issue
6
Pages
621-632
ISSN
  • 0269-8811 (ISSN-L)
  • 1461-7285
OpenAlex
W2119738402
Cited by
905
References
49
Citations by year
2026: 57 · 2025: 98 · 2024: 89 · 2023: 89 · 2022: 101 · 2021: 79 · 2020: 65 · 2019: 29 · 2018: 54 · 2017: 44 · 2016: 46 · 2015: 16 · 2014: 31 · 2013: 24 · 2012: 26
FWCI
20.58
Type
journal article
Language
en
Open access
Locations
  • Journal of Psychopharmacology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Heffter Research Institute
  • National Institute on Drug Abuse (R01DA003889)
Topics
  • Social Sciences › Psychology › Clinical Psychology › Psychedelics and Drug Studies
  • Social Sciences › Health › Religion, Spirituality, and Psychology
  • Social Sciences › Psychology › Social Psychology › Paranormal Experiences and Beliefs
Keywords
psilocybin, mystical experience, personal meaning, spiritual meaning, long-term effects, life satisfaction, well-being, spirituality, religious experience, personality, quality of life
MeSH terms
Administration, Oral, Adult, Affect, Female, Follow-Up Studies, Hallucinogens, Humans, Male, Middle Aged, Mysticism, Personality, Psilocybin, Quality of Life, Surveys and Questionnaires, Religion, Time Factors, Knowledge, Spirituality

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review