Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance

This is one of the first (and key) double-blind, placebo-controlled studies (n=36) on psilocybin and its effect on ‘healthy normals’. It shows that a high (30mg/70kg) dose can occasion mystical (peak) experiences (participants did already have a spiritual/religious practice beforehand). The experience is rated as personally meaningful. The participants exhibit positive mood (and lower anxiety) immediately and after two months.

Abstract of Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance

Rationale Although psilocybin has been used for centuries for religious purposes, little is known scientifically about its acute and persisting effects.

Objectives This double-blind study evaluated the acute and longer-term psychological effects of a high dose of psilocybin relative to a comparison compound administered under comfortable, supportive conditions.

Materials and methods The participants were hallucinogen-naïve adults reporting regular participation in religious or spiritual activities. Two or three sessions were conducted at 2-month intervals. Thirty volunteers received orally administered psilocybin (30 mg/70 kg) and methylphenidate hydrochloride (40 mg/70 kg) in counterbalanced order. To obscure the study design, six additional volunteers received methylphenidate in the first two sessions and unblinded psilocybin in a third session. The 8-h sessions were conducted individually. Volunteers were encouraged to close their eyes and direct their attention inward. Study monitors rated volunteers’ behavior during sessions. Volunteers completed questionnaires assessing drug effects and mystical experience immediately after and 2 months after sessions. Community observers rated changes in the volunteer’s attitudes and behavior.

Results Psilocybin produced a range of acute perceptual changes, subjective experiences, and labile moods including anxiety. Psilocybin also increased measures of mystical experience. At 2 months, the volunteers rated the psilocybin experience as having substantial personal meaning and spiritual significance and attributed to the experience sustained positive changes in attitudes and behavior consistent with changes rated by community observers.

Conclusions When administered under supportive conditions, psilocybin occasioned experiences similar to spontaneously occurring mystical experiences. The ability to occasion such experiences prospectively will allow rigorous scientific investigations of their causes and consequences.”

Authors: Roland R. Griffiths, William A. Richards, Una D. McCann & Robert Jesse

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Summary of Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning & spiritual significance

Psilocybin, a naturally occurring tryptamine alkaloid, is the principal psychoactive component of a genus of mushrooms. It causes significant alterations in perceptual, cognitive, affective, volitional, and somesthetic (touch/tactile) functions.

Early clinical research with psilocybin did not recognize the powerful influences of set and setting. Still, later research included more preparation and interpersonal support during the period of drug action, and found fewer adverse psychological effects and increased reports of positively valued experiences.

The study used double-blind clinical pharmacology methods to evaluate the mood-altering and psychological effects of psilocybin in 36 well-educated, hallucinogen-naive volunteers.

Further Notes

Griffiths et al (2008) do a 14-month follow-up and find that the mystical experience mediates personal meaning and spiritual significance.

This paper is included in the meta-analytical review by Galvão-Coelho and colleagues (2021) that found psychedelics to improve mood (for those with mood disorders) both in the short and long term (up to 60 days).

“The study compared psilocybin (30 mg/70 kg) and methylphenidate hydrochloride (40 mg/70 kg) using a double-blind between-group, crossover design that involved two or three 8-h drug sessions conducted at 2-month intervals. Thirty-six volunteers were randomly assigned to receive either two sessions (N=30) or three sessions (N=6).” (only the data of the two-session group was used in the analysis)

The participants were ‘healthy-normals’. Many had enjoyed higher education, and none had a family history of schizophrenia. The placebo used was methylphenidate (Ritalin), so there was some blinding, but of course, not everyone was fooled by the active placebo.

[P]silocybin produced significantly greater elevations in ratings of positive attitudes, mood, social effects, and behavior; the negative ratings of these same dimensions were very low and did not differ across the drug conditions. This questionnaire also included ratings of the personal meaningfulness and spiritual significance of the experience and whether the experience changed their sense of well-being or life satisfaction. Table 4 shows that these ratings were significantly higher after psilocybin than after methylphenidate. It is remarkable that 67% of the volunteers rated the experience with psilocybin to be either the single most meaningful experience of his or her life or among the top five most meaningful experiences of his or her life.”

Research consistently finds that participants rate the psychedelic experience as one of the most meaningful ones in their life. This is (at least in this case) without any further prompting/priming/preparations of the participant except to tell them about what they can expect.

“In written comments about their answers, the volunteers often described aspects of the experience related to a sense of unity without content (pure consciousness) and/or unity of all things.”

“None of the factors on the two widely used questionnaires assessing five factors of personality (NEO and PI-R) and measures of general positive and negative affect (PANAS-X) was differentially affected by psilocybin. At screening and at 2 months after session 1, there were no significant differences between the group that received psilocybin on the first session (N=15) and the group that received methylphenidate on the first session (N=15). Furthermore, within the latter group, there were no significant changes from post-session 1 to postsession 2.”

Although the sessions were impactful, they did not elicit changes in personality or positive/negative affect. This is a different result from a later study by Griffiths et al. (2011) that found increases in the personality measure openness.

“An important finding of the present study is that, with careful volunteer screening and preparation and when sessions are conducted in a comfortable, well-supervised setting, a high dose of 30 mg/70 kg psilocybin can be administered safely. It is also noteworthy that, despite meetings and prior sessions with monitors ranging from 8 h (when psilocybin was administered on the first session) up to 24 h (when psilocybin was administered on the third session) of contact time, 22% (8 of 36) of the volunteers experienced a period of notable anxiety/dysphoria during the session, sometimes including transient ideas of reference/ paranoia.”

So, although about 1 in 5 experienced anxiety, no (pharmacological) interventions were needed. The authors also report that none of the participants reported negative (psychological) outcomes in the follow-up.

“To date, there have been no reports of persisting perceptional phenomena sometimes attributed to hallucinogen use or of recreational abuse of hallucinogens, and all participants appear to continue to be high-functioning, productive members of society.”

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Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance

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Cite this paper (APA)

Griffiths, R. R., Richards, W. A., McCann, U., & Jesse, R. (2006). Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology187, 268-283.

Study details

Compounds studied

Topics studied
Healthy Subjects

Study characteristics
Original Placebo-Controlled Active Placebo Double-Blind Within-Subject Randomized

36 Humans


Authors associated with this publication with profiles on Blossom

Roland Griffiths
Roland R. Griffiths is one of the strongest voices in psychedelics research. With over 400 journal articles under his belt and as one of the first researchers in the psychedelics renaissance, he has been a vital part of the research community.

William Richards
William A. 'Bill' Richards is one of the pioneering psychedelic researchers (Johns Hopkins), a teacher at CIIS, and clinician in private practice.

Bob Jesse
Robert 'Bob' Jesse is one of the hidden movers and shakers in the psychedelics renaissance. He founded the Council on Spiritual Practices. Together with Roland Griffiths (and many others), he led the new research into psychedelics, also with a focus beyond the ill, but too for people for spiritual and psychological benefits.


Institutes associated with this publication

Johns Hopkins University
Johns Hopkins University (Medicine) is host to the Center for Psychedelic and Consciousness Research, which is one of the leading research institutes into psychedelics. The center is led by Roland Griffiths and Matthew Johnson.

Compound Details

The psychedelics given at which dose and how many times

Psilocybin 30 mg | 1x

Linked Research Papers

Notable research papers that build on or are influenced by this paper

Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness
This re-analysis from two psilocybin trials with hallucinogen-naïve subjects (n=52) looked at personality changes in participants. It found significant increases in openness (but not neuroticism, extroversion, agreeableness, and conscientiousness), which remained higher than baseline for those who had a mystical experience up to a year.

Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later
This follow-up study (n=36) found that the mystical experience on the day of the psychedelic experience (58% had a 'full' experience) with psilocybin (30mg/70kg) mediated the level of personal meaning and spiritual significance reported 14 months later.

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