Griffiths 2006: The Psilocybin Study That Changed Everything

Psilocybin and the Mystical Experience

36 hallucinogen-naive adults

In 2006, Roland Griffiths enrolled 36 carefully screened hallucinogen-naive adults in a double-blind trial at Johns Hopkins, the first rigorous clinical psilocybin study in four decades. 61% had a complete mystical experience.

Griffiths et al., Psychopharmacology, 2006

61%

of volunteers (22 of 36) met a priori criteria for a complete mystical experience on high-dose psilocybin, versus 11% (4 of 36) on the active control

58%

still ranked the experience among the five most personally meaningful of their lives at 14-month follow-up (Griffiths, 2008)

31%

reported strong or extreme fear at some point during the session, in the same carefully screened, individually monitored sample

Griffiths et al., Psychopharmacology, 2006

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In 1962, Walter Pahnke administered psilocybin to theological seminary students in the basement of Marsh Chapel during a Good Friday service. Twenty students took part; ten received 30 mg of psilocybin and ten received nicotinic acid as a comparison. Those who received psilocybin scored significantly higher on Pahnke's mystical experience questionnaire and reported positive changes in attitudes and behaviour at six months and again at a 25-year follow-up.^[1] But the experiment was never replicated. Its methodology was criticised. Psilocybin was classified Schedule I in 1970, clinical research stopped, and for the next four decades the question of whether psilocybin could reliably produce meaningful experiences under controlled conditions went unanswered in peer-reviewed science.

The Griffiths 2006 psilocybin study changed that. Roland Griffiths and colleagues at Johns Hopkins designed and published the first rigorous, double-blind clinical trial of psilocybin in four decades. They found that 61% of 36 hallucinogen-naive adults met strict pre-specified criteria for a complete mystical experience, that a majority rated it among the five most personally meaningful events of their lives, and that these ratings persisted to 14 months.^[1][2] The paper appeared in Psychopharmacology, one of the field's leading journals, and was published alongside invited commentaries from senior figures in addiction and pharmacology research — an editorial signal that the journal regarded it as consequential rather than fringe.

For the broader picture of what psilocybin does pharmacologically, the complete psilocybin pharmacology guide provides the foundational context.

Why 2006 and Not Earlier: The Four Decades of Missing Clinical Science

Psilocybin research didn't simply slow down after the 1960s. It stopped. The Controlled Substances Act of 1970 placed psilocybin on Schedule I, the most restrictive classification in American drug law. Schedule I drugs are defined as having no accepted medical use and high potential for abuse. Research required a DEA Schedule I researcher licence, institutional approval, a DEA-registered storage vault, and an FDA IND application. The practical barriers were sufficient to make almost no researcher attempt it.

The problem was not only regulatory. The earlier era of psychedelic research had been tainted by association with Timothy Leary, whose advocacy for LSD and dismissal of scientific protocol had generated a public and institutional backlash that contaminated the entire class of compounds in the eyes of mainstream science. Any researcher proposing to study psilocybin in 1985 or 1993 would have faced intense scepticism, not about psilocybin specifically, but about the field's credibility and their own.

Griffiths had credibility to spend. He was a behavioural pharmacologist with an established career studying caffeine and drugs of abuse. He had no prior advocacy work around psychedelics. When he began designing the 2006 study, his explicit goal was to produce data that would be un-dismissable on methodological grounds. Everything about the design was constructed to preempt the obvious criticisms from that earlier era.

How the Study Was Designed to Be Scientifically Un-Dismissable

The Griffiths team made a series of specific methodological choices that distinguish the 2006 study from earlier psychedelic research, each addressing a potential objection.^[1]

The participants were hallucinogen-naive: they had no prior experience with any psychedelic drug. This excluded the possibility that prior experiences were generating demand characteristics or inflating mystical experience scores through wishful interpretation. If someone with no prior psychedelic exposure reported a complete mystical experience, it was harder to attribute to expectation than if the sample had been drawn from the psychedelic community.

The comparison drug was methylphenidate (Ritalin) at 40 mg/70 kg — a stimulant with no psychedelic properties that nonetheless produces noticeable subjective effects with a similar onset and duration. An inert placebo would have made blinding impossible, since psilocybin's effects are unmistakable. Using an active comparator that participants could plausibly misidentify as the experimental drug preserved the blind. The design went further still: thirty volunteers received psilocybin and methylphenidate in counterbalanced order across two sessions, while six additional volunteers received methylphenidate in their first two sessions and unblinded psilocybin in a third, specifically to obscure the study design from participants and monitors.

Trained monitors were present throughout each session. Two well-trained support staff remained with each participant for the full 8-hour session, with standardised protocols for responding to difficult experiences; if a participant reported significant fear or anxiety, monitors provided verbal reassurance or supportive physical contact. Preparation meetings before the session day and integration meetings afterward were standard, with monitor contact time ranging from at least 8 hours up to 24 hours. Sessions were conducted individually, with eyeshades and a fixed classical music programme. The room was designed to feel safe and comfortable, not clinical. About 25% of sessions were videotaped and reviewed by the first author to verify that procedures were followed.

The outcome measure was the Pahnke–Richards Mystical Experience Questionnaire, which quantifies the internal experience rather than relying on global impressions. "Did you have a meaningful experience?" is a question that could be answered positively by social desirability bias. The questionnaire instead required participants to rate specific phenomenological dimensions, and the threshold for a "complete" mystical experience was demanding.

How the Threshold Worked

Six Scales, All Six Required

“Complete mystical experience” was a pre-registered arithmetic rule, not a judgement call. Each of the six scales below had to reach at least 0.6 of its maximum possible score. Missing any one of them meant the session did not count — however intense the others were.

1. 1

   Unity

   ≥ 0.60 of max

   Internal (pure awareness, merging with ultimate reality) or external (all things are alive, all is one) — whichever scored higher
2. 2

   Transcendence of time and space

   ≥ 0.60 of max

   Loss of the ordinary sense of when and where the experience is happening
3. 3

   Ineffability and paradoxicality

   ≥ 0.60 of max

   The claim that the experience cannot be adequately put into words
4. 4

   Sense of sacredness

   ≥ 0.60 of max

   Awe; the experience being met as holy or worthy of reverence
5. 5

   Noetic quality

   ≥ 0.60 of max

   A conviction of having gained intuitive knowledge of ultimate reality
6. 6

   Deeply-felt positive mood

   ≥ 0.60 of max

   Joy, peace, love — not mere pleasantness

All six clear the line → scored as a complete mystical experience. Under 30 mg/70 kg psilocybin, 22 of 36 volunteers (61%) did. Under the methylphenidate control, 4 of 36 (11%) did.

Coverage describing this as a four-dimension threshold is reaching for the revised MEQ30, a later instrument with a four-factor structure. The 2006 study used the earlier Pahnke–Richards questionnaire, which assesses seven domains and scores six.

Source: Griffiths et al., Psychopharmacology, 2006 [ref 1].

What 61% of Participants Actually Experienced

At the high psilocybin dose (30 mg/70 kg), 22 of the 36 volunteers — 61% — met the pre-specified criteria for a complete mystical experience. After methylphenidate, 4 of 36 (11%) did.^[1] The gap is the finding. The control rate is not zero, which matters: a small number of people cross this threshold on a stimulant, under supportive conditions, with eyeshades and music. But the psilocybin rate is roughly five and a half times higher, large enough to establish that psilocybin reliably occasions these states — not for everyone, not at all doses, but at a rate that places it in a different category from other pharmacological interventions.

For context, Griffiths noted that 61% was somewhat higher than the 30–40% Pahnke reported in the Good Friday Experiment, and attributed the difference to the longer preparation time and the individual, eyeshade-and-music setting rather than Pahnke's group religious service.

At 2-month follow-up, 67% of volunteers rated the psilocybin experience as either the single most meaningful experience of their lives or among their top five. On spiritual significance, 33% called it the single most spiritually significant experience of their lives, with a further 38% placing it in their top five. For context: these were adults who had been living full lives with births, deaths, marriages, career achievements, and losses. A single drug session was ranking alongside those events. One caveat on these particular figures: the 2-month questionnaire was completed by 24 of the 36 volunteers, so they describe that subgroup rather than the full sample.

Community observers — friends, family members, and colleagues nominated by participants, with ratings available for 26 volunteers — corroborated the reports. They described participants as more positive, more flexible, more emotionally engaged, and kinder in the months following the session. This external validation mattered for ruling out one alternative explanation: that participants were reporting changes because they felt they were supposed to, or because they were invested in the study's success. People around them were noticing changes they had not been told to expect.

Number Provenance

Four Correct Percentages, Four Different Questions

Every figure below is accurately reported in a peer-reviewed paper. They differ because each answers a different question, on a different sample, at a different moment. Quoting one as “the psilocybin mystical-experience rate” discards the sample and the timepoint that give it meaning.

61%22 of 36 volunteers

Griffiths 2006 [ref 1]All 36 enrolled volunteers· Immediately after the session

Met a priori Pahnke criteria for a "complete" mystical experience after 30 mg/70 kg psilocybin. This is the headline rate of the original paper.

11%4 of 36 volunteers

Griffiths 2006 [ref 1]The same 36, active-control session· Immediately after the session

Met the identical criteria after methylphenidate. The control rate is low but not zero — a detail routinely dropped when the finding is retold.

58%of 36 volunteers

Griffiths 2008 [ref 2]The same 2006 cohort· 14 months later

Still met criteria for having had a complete mystical experience when the session was re-rated over a year on. Slightly below the immediate rate, not above it.

72%of 18 volunteers

Griffiths 2011 [ref 3]A separate 18-person trial· At the two highest doses only

Had a mystical-type experience at 20 and/or 30 mg/70 kg in a dose-effect study — a different design, a different sample, and a rate conditioned on receiving a high dose.

Figures often attached to the wrong claim

• 67%Two separate quantities in the 2006 paper: the proportion meeting complete-mystical criteria among those dosed on the FIRST session specifically (67%, versus 60% on the second and 50% on the third), and — unrelatedly — the share rating the experience among their top five most personally meaningful at 2 months.
• 71%The 2-month spiritual-significance rating in 2006: 33% called it the single most spiritually significant experience of their life, plus a further 38% placing it in their top five.

Sources: Griffiths et al., Psychopharmacology, 2006 [ref 1]; Griffiths et al., Journal of Psychopharmacology, 2008 [ref 2]; Griffiths et al., Psychopharmacology, 2011 [ref 3].

The Half of the 2006 Paper That Rarely Gets Retold

The same 36 volunteers, in the same sessions that produced those results, also had a substantial rate of frightening experiences — and the 2006 paper reports it with the same precision it applies to the positive outcomes.^[1]

Eleven of the 36 volunteers (31%) rated their experience of fear during the session as "strong" or "extreme." None did so after methylphenidate. Eight volunteers (22%) had a sustained period of notable anxiety or dysphoria: for four of them the entire session was dominated by it, and for four others a significant portion was. Six of those eight had mild, transient ideas of reference or paranoid thinking during the hours after dosing. Two compared the experience to being in a war.

The counterweight belongs in the same breath, and it is equally precise: no volunteer required pharmacological intervention. Every difficult experience was managed with reassurance from the monitors, and the effects did not persist beyond the session. The primary monitor remained reachable by phone for 24 hours afterward.

One result here is genuinely counterintuitive. More preparation did not reduce difficulty. Anxiety and dysphoria occurred whether psilocybin was administered on the first session, the second, or the third — meaning that neither longer monitor contact nor being unblinded to the drug was protective.

The Half That Gets Left Out

Difficult Experiences in the Same 36 Volunteers

These figures come from the same paper, the same sample, and the same sessions as the 61% mystical-experience result. The volunteers were hallucinogen-naive, psychologically screened, individually monitored by two trained staff, and had at least eight hours of prior contact with them.

31%11 of 36Strong or extreme fear

Rated their "experience of fear" at some point in the session as strong or extreme after psilocybin. None did after methylphenidate.

22%8 of 36Notable anxiety or dysphoria

Had a sustained period of anxiety or unpleasant psychological struggle — for four of them, the entire session; for four others, a significant portion of it.

17%6 of 36Transient ideas of reference or paranoia

Mild, passing paranoid thinking during the hours after dosing. All six were among the eight with a notable anxiety/dysphoria response.

0of 36Required pharmacological intervention

Every difficult experience was managed with verbal or physical reassurance from the monitors and did not persist beyond the session.

Preparation did not prevent it

Anxiety and dysphoria occurred whether psilocybin was given on the first session (two volunteers), the second (four), or the third (two). Longer monitor contact — ranging from 8 up to 24 hours — and being unblinded to the drug were not protective. In the separate 2011 dose-effect trial, 39% of volunteers had extreme anxiety or fear at the 20 and 30 mg/70 kg doses [ref 3].

The authors’ own reading: the risks of hallucinogen use should not be underestimated, and under unmonitored conditions these effects could escalate to panic and dangerous behaviour.

Sources: Griffiths et al., Psychopharmacology, 2006 [ref 1]; Griffiths et al., Psychopharmacology, 2011 [ref 3].

Safety

Critical

These results describe a highly controlled clinical setting, not recreational use

Concern

Even among volunteers who were medically screened, psychologically stable, hallucinogen-naive, individually monitored by two trained staff, and prepared over 8 or more hours of prior contact, 31% experienced strong or extreme fear and 22% had a period of notable anxiety or dysphoria, sometimes with transient paranoid thinking.

What the research says

The study's own authors argue explicitly that the risks of hallucinogen use should not be underestimated, and note that under unmonitored conditions such effects could escalate to panic and dangerous behaviour. The absence of serious harm in this trial is a property of the screening, preparation, and monitoring — not of the drug alone.

Particularly relevant for: Psilocybin remains a Schedule I substance in the United States outside of authorised research and specific state-regulated programmes. Risks are substantially higher for people with personal or family histories of psychotic disorders, who were excluded from this trial.

What to do

This article describes research findings and is not medical advice. Nothing here should be read as guidance for using psilocybin outside a legally authorised, medically supervised setting. Discuss any question about psychedelic treatment with a qualified clinician.

Griffiths et al., Psychopharmacology, 2006 [ref 1]

For understanding how psilocybin's 5-HT2A mechanism generates these experiences at the neurological level, the 5-HT2A agonism explainer covers the pharmacological chain from receptor activation to subjective state.

The 14-Month Follow-Up: Why This Is More Than a Drug Paper

The 2006 publication reported 2-month outcomes. The more striking data came from the 14-month follow-up, published by Griffiths and colleagues in the Journal of Psychopharmacology in 2008.^[2]

Key Study

Griffiths et al. (2008) · Journal of Psychopharmacology

Population

The same 36 hallucinogen-naive adults from the 2006 trial, all reporting regular participation in religious or spiritual activities

Intervention

A single oral dose of psilocybin, 30 mg/70 kg, given in one of two or three monitored 8-hour sessions

Comparator

Methylphenidate, 40 mg/70 kg, administered in the other session(s)

Finding

At 14 months, 58% rated the psilocybin session among the five most personally meaningful experiences of their lives and 67% among the five most spiritually significant; 11% and 17% respectively called it the single most. 64% said it increased their wellbeing or life satisfaction, 61% reported moderate-to-extreme positive behaviour change, and 58% still met criteria for a complete mystical experience. Ratings did not differ significantly from the 2-month assessment.

positive Robust and independently corroborated by community observers, but in a small, self-selected, spiritually-oriented sample with no comparison group receiving a different intervention.

Griffiths et al., Journal of Psychopharmacology, 2008 [ref 2]

These were not marginal or narrowly positive results. They represented a majority of participants reporting sustained life changes from a single pharmacological experience lasting one working day. Notably, of all the personality, affect, quality-of-life and spirituality measures assessed across the study, only the mystical experience scale showed a difference from screening — the change was specific rather than a general uplift.

The community observer reports at 14 months continued to corroborate participant self-report. This matters because it rules out a straightforward demand characteristic explanation: at 14 months, participants were reporting to researchers they had not had sustained contact with. The observers had their own independent perspective.

One selection limitation applies and should not be ignored. Participants were recruited specifically for regular participation in religious or spiritual activities. This was deliberate: Griffiths reasoned that people already oriented toward spiritual experience would have a framework for interpreting and integrating mystical states, reducing the risk of difficult experiences and increasing the chance of meaningful ones. The volunteers were also, in the authors' own description, well educated, psychologically stable, and middle-aged. It means the results describe a specific population. Whether hallucinogen-naive adults with no prior spiritual interest would show the same outcomes is an open question the study does not answer — and the authors say so directly.

For the question of how this mediating experience translates into concrete therapeutic outcomes across different conditions, the how the mystical experience predicts therapeutic outcomes article covers that data.

The Dose-Response Confirmation: Effects Are Not All-or-Nothing

Five years after the 2006 paper, Griffiths and colleagues published a dose-effect study examining how psilocybin dose affects the probability and intensity of mystical experience.^[3] This was a separate trial with a new sample — 18 adults, 17 of them hallucinogen-naive — who each received five doses (0, 5, 10, 20 and 30 mg/70 kg) in 8-hour sessions at one-month intervals, randomised to ascending or descending order.

The finding was clear: both the acute and the persisting effects of psilocybin were generally a monotonically increasing function of dose. At the two highest doses, 72% of volunteers had a mystical-type experience. One month after those sessions, volunteers rated the experience as having substantial personal and spiritual significance, and at 14 months those ratings were undiminished and consistent with changes rated by community observers. The ascending dose sequence produced greater positive effects than the descending one.

The graded nature of the effect supported a pharmacological rather than purely expectancy-based account: if the experiences were purely placebo, they should not show a monotonic dose-response gradient under blinded conditions. The implication for clinical research was that dose is a meaningful therapeutic lever.

But the same dose gradient runs in both directions. At those same two highest doses, 39% of volunteers experienced extreme anxiety or fear. Turning the dose up increases the probability of a complete mystical experience and the probability of a frightening one together — which is precisely why dose selection in clinical psilocybin research is a trade-off rather than a maximisation.

For readers interested in the specific doses used in clinical research and how they translate to different experience types, the psilocybin dose-response curve article covers the full gradient from threshold to heroic doses.

The Unexpected Outcome: One Drug Session Shifted Personality More Than a Year Later

The most striking and debated finding from this research programme came from MacLean, Johnson, and Griffiths (Journal of Psychopharmacology, 2011), who analysed Big Five personality data from 51 participants across Griffiths lab studies.^[4]

The Big Five model of personality identifies five broad dimensions: Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. A large body of longitudinal evidence suggests these core traits are predominantly stable in adults after about age 30. They shift gradually over a lifetime, and their trajectories are not substantially altered by typical life events or interventions. As the authors noted, no prior study had demonstrated personality change in healthy adults following a single experimentally manipulated event.

Participants showed significant increases in Openness following a high-dose psilocybin session. Critically, in those who had a mystical experience during the session, Openness remained significantly higher than baseline more than a year afterward. The durable trait-level shift was specific to the mystical experience quality, not to psilocybin exposure per se.

Fact Check

Does one psilocybin session permanently change your personality?

The claim

“A single psilocybin session permanently rewires your personality.”

Popular coverage of the MacLean 2011 Openness finding, often compressed to 'psychedelics change who you are'.

What research shows

Overstated

MacLean and colleagues found a significant, durable increase in one of five traits — Openness — measured more than a year after a high-dose session, and only in participants who had a mystical-type experience. Those who received psilocybin without such an experience did not show the durable change.

One trait, not personality wholesale. 'More than a year' is the longest interval measured, which is not the same as permanent. The sample was 51 volunteers, self-selected for interest in spiritual practice, and there was no non-psilocybin comparison group followed over the same interval. It remains among the most discussed and contested results in the literature.

MacLean, Johnson & Griffiths, Journal of Psychopharmacology, 2011 [ref 4]

This finding is the outlier in the 2006 study family. A 2-month or 14-month change in wellbeing is surprising but interpretable. A change in trait personality persisting beyond a year from a single pharmacological session is a different category of claim, and it deserves the scrutiny it continues to receive.

For background on how oceanic boundlessness and ego dissolution, the specific experiential features most associated with these outcomes, are defined and measured, the oceanic boundlessness and ego dissolution article covers that topic directly. The broader mystical experience overview, including the 2025 Romeo meta-analysis confirming that experience intensity predicts outcomes across studies, is in the psilocybin and the mystical experience overview.

The Bottom Line

The Griffiths 2006 study was the first rigorous double-blind clinical trial of psilocybin in four decades. Under a demanding six-scale threshold, 61% of 36 hallucinogen-naive adults (22 of 36) had a complete mystical experience at high dose, against 11% on the active comparator methylphenidate. At 2 months, 67% rated it among the five most personally meaningful experiences of their lives; at 14 months (Griffiths 2008), 58% still did, with 64% reporting increased wellbeing — corroborated by community observers. The same sessions produced strong or extreme fear in 31% of volunteers and notable anxiety or dysphoria in 22%, though none required drug treatment. The MacLean 2011 follow-on found durable Openness increases only in participants who had a mystical experience. The study's key contribution was methodological rigour that preempted the criticism which had undermined earlier-era research; its key limitations are a small sample selected for existing spiritual engagement and the absence of an active non-psilocybin comparison followed long-term.

Frequently Asked Questions

What did the Griffiths 2006 psilocybin study find?

The study found that 22 of 36 hallucinogen-naive adults — 61% — given a high dose of psilocybin (30mg/70kg) met pre-specified criteria for a complete mystical experience, compared with 4 of 36 (11%) on the active comparator methylphenidate. At 2-month follow-up, 67% rated the experience as the single most meaningful of their lives or among their top five. At 14 months (Griffiths 2008), 58% still placed it in their top five most personally meaningful and 67% in their top five most spiritually significant, with community observers corroborating sustained positive behavioural changes. The same paper reports that 31% of volunteers experienced strong or extreme fear during the session.

What counts as a 'complete' mystical experience in this research?

It was a pre-registered arithmetic threshold, not a clinical judgement. Using the Pahnke–Richards Mystical Experience Questionnaire, a volunteer had to score at least 0.6 of the maximum possible on every one of six scales: unity (internal or external, whichever was higher), transcendence of time and space, ineffability and paradoxicality, sense of sacredness, noetic quality, and deeply-felt positive mood. Falling short on any single scale meant the session did not qualify. Descriptions of a four-dimension threshold refer to the later revised MEQ30, a different instrument from the one used in 2006.

How was the Griffiths 2006 study different from Leary's research?

Griffiths used a double-blind design with an active comparison drug (methylphenidate), enrolled hallucinogen-naive adults with no prior psychedelic experience, used validated quantitative outcome measures with pre-specified thresholds, included two trained monitors throughout each individual session, conducted pre-session preparation and post-session integration, videotaped and audited a sample of sessions, and published in a peer-reviewed pharmacology journal. Leary's work lacked rigorous controls, enrolled participants with prior psychedelic experience, and was conducted without formal clinical protocols, making systematic replication impossible.

Were there any bad reactions in the Griffiths psilocybin study?

Yes, and the paper documents them in detail. Eleven of the 36 volunteers (31%) rated their experience of fear during the psilocybin session as strong or extreme, and none did after methylphenidate. Eight volunteers (22%) had a period of notable anxiety or dysphoria — for four of them the entire session. Six of those eight had mild, transient ideas of reference or paranoid thinking. No volunteer required pharmacological intervention, and effects were managed with reassurance and did not persist beyond the session. Longer preparation did not prevent these reactions. The authors explicitly warn that under unmonitored conditions such effects could escalate to panic and dangerous behaviour.

How many people were in the Griffiths psilocybin study?

The original 2006 study enrolled 36 participants: 30 received psilocybin and methylphenidate in counterbalanced order, and 6 additional volunteers received methylphenidate in their first two sessions plus unblinded psilocybin in a third, to obscure the design. The 2011 dose-effect study was a separate trial with 18 participants. The MacLean 2011 personality paper analysed 51 participants from Griffiths lab studies. Sample sizes in this research area are modest by large-trial standards; the significance of the 2006 study came from its design and the magnitude of observed effects, not its sample size.

Why was the 2006 psilocybin study published in Psychopharmacology important?

Psychopharmacology is a leading peer-reviewed journal in the field; publication required passing scientific peer review at a venue that would not be dismissible as alternative medicine or advocacy publishing. The paper was published alongside invited commentaries from senior researchers, an editorial signal that the journal treated it as consequential. Importantly, the study demonstrated that rigorous controlled research on psilocybin was possible and publishable, establishing the methodological template for subsequent Johns Hopkins, NYU, and Imperial College London trials that followed over the next 20 years.

What is the Johns Hopkins psilocybin study?

The Johns Hopkins psilocybin study typically refers to the Griffiths 2006 study, the foundational double-blind trial published in Psychopharmacology. The Johns Hopkins Center for Psychedelic and Consciousness Research has since conducted multiple follow-on trials for depression, addiction (tobacco, alcohol), and other conditions. The 2006 study is specifically the one that established the mystical experience finding in a healthy volunteer sample; the Openness personality result came from the related MacLean 2011 analysis.

Sources & References

1. 1RTHM-00096·Griffiths, R R et al. (2006). “Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance..” Psychopharmacology.Study breakdown →PubMed →↩
2. 2RTHM-00250·Griffiths, Roland R et al. (2008). “Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later..” Journal of Psychopharmacology.Study breakdown →PubMed →↩
3. 3RTHM-00396·Griffiths, Roland R et al. (2011). “Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects..” Psychopharmacology.Study breakdown →PubMed →↩
4. 4RTHM-00422·MacLean, Katherine A et al. (2011). “Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness..” Journal of psychopharmacology (Oxford.Study breakdown →PubMed →↩