Journal of Psychopharmacology
November 30, 2016
Annie Umbricht, Mary P Cosimano, Roland R. Griffiths et al.
2,174 citations
In cancer patients with life-threatening diagnoses and symptoms of depression or anxiety, a high dose of psilocybin (22 or 30 mg/70 kg) produced large decreases in depressed mood and anxiety, along with increases in quality of life, life meaning, and optimism, and decreases in death anxiety, compared with a very low placebo-like dose (1 or 3 mg/70 kg). At 6-month follow-up, about 80% of participants continued to show clinically significant decreases in depressed mood and anxiety. Participants attributed improvements in attitudes about life, mood, relationships, and spirituality to the high-dose experience, with over 80% endorsing moderately or greater increased well-being or life satisfaction. The mystical-type experience during the session mediated the effect of dose on therapeutic outcomes.
Psychopharmacology
July 7, 2006
Roland R. Griffiths, William A. Richards, U. Mccann et al.
1,684 citations
A high dose of psilocybin, given under supportive conditions to hallucinogen-naïve adults who regularly participate in religious or spiritual activities, produced acute perceptual changes, subjective experiences, and labile moods including anxiety. It also increased measures of mystical experience. Two months later, volunteers rated the psilocybin experience as having substantial personal meaning and spiritual significance and attributed sustained positive changes in attitudes and behavior to it, consistent with ratings by community observers. The ability to prospectively occasion such experiences allows rigorous scientific investigation of their causes and consequences.
JAMA Psychiatry
November 4, 2020
Mary P Cosimano, Alan K. Davis, Frederick S. Barrett et al.
1,269 citations
Two doses of psilocybin (20 and 30 mg per 70 kg) combined with supportive psychotherapy produced large, rapid antidepressant effects in adults with major depressive disorder who were not taking other antidepressants. In a randomized waiting list-controlled trial with 24 completers, depression scores on the GRID-Hamilton scale dropped from a mean of 22.8 at baseline to 8.0 one week after the second session, compared with 23.8 at the same time point in the delayed-treatment group. Seventy-one percent of participants showed a clinically significant response at week 1, and 58% met remission criteria. Effects persisted through the four-week follow-up.
Journal of Psychopharmacology
September 11, 2014
Mary P Cosimano, Matthew W. Johnson, Albert Garcia‐romeu et al.
910 citations
In an open-label pilot study, 15 nicotine-dependent smokers received moderate (20 mg/70 kg) and high (30 mg/70 kg) doses of psilocybin as part of a structured 15-week smoking cessation program. At 6-month follow-up, 12 of 15 participants (80%) showed seven-day point prevalence abstinence, a rate substantially exceeding the typical 35% or less reported for other behavioral or pharmacological therapies. The authors note the open-label design prevents definitive conclusions about efficacy, but the findings suggest psilocybin may be a potentially useful adjunct to smoking cessation treatment.
The American Journal of Drug and Alcohol Abuse
July 21, 2016
Matthew W. Johnson, Albert Garcia‐romeu, Roland R. Griffiths
702 citations
A follow-up of a small pilot study found that two to three moderate to high doses of psilocybin (20 and 30 mg/70 kg) combined with cognitive behavioral therapy for smoking cessation led to high long-term abstinence rates. At 12 months, 10 of 15 participants (67%) were confirmed abstinent; at a longer follow-up averaging 30 months, 9 participants (60%) remained abstinent. Most participants rated the psilocybin experiences among the five most personally meaningful and spiritually significant events of their lives. The results suggest psilocybin, within a structured treatment program, holds promise for promoting long-term smoking abstinence and warrants further research.
Journal of Psychopharmacology
August 31, 2016
Theresa M. Carbonaro, Matthew P. Bradstreet, Frederick S. Barrett et al.
541 citations
In a survey of 1,993 people who recalled their worst 'bad trip' after taking psilocybin mushrooms, 39% ranked it among the top five most challenging experiences of their lives. Eleven percent put themselves or others at risk of physical harm, with factors such as higher dose, longer duration, and lack of physical comfort or social support increasing that risk. About 2.6% acted aggressively and 2.7% needed medical help. Among those whose experience was more than a year prior, 7.6% sought treatment for lasting psychological symptoms, with three cases linked to enduring psychotic symptoms and three to attempted suicide. Despite difficulties, 84% reported benefiting from the experience. The incidence of risky behavior or lasting distress is very low when psilocybin is given in controlled laboratory settings.
ACS Pharmacol Transl Sci
December 10, 2020
David B. Yaden, Roland R. Griffiths
534 citations
Classic psychedelics induce altered states of consciousness that people often find meaningful. In human studies, when the overall intensity of drug effects is statistically controlled, specific subjective experiences—not just neurobiological changes—predict therapeutic and other positive outcomes. The authors argue that these subjective effects are necessary for lasting benefits and account for most of the improvement, while underlying brain mechanisms are likely necessary but insufficient on their own.
Journal of Psychopharmacology
October 11, 2017
Roland R. Griffiths, Matthew W. Johnson, William A. Richards et al.
528 citations
A double-blind trial compared a high dose of psilocybin (20 and 30 mg/70 kg) with a very low dose (1 mg/70 kg) in healthy adults who also undertook a program of meditation and spiritual practices. At six months, the high-dose groups, compared with the low-dose group, showed large, significant positive changes in interpersonal closeness, gratitude, life meaning, forgiveness, death transcendence, daily spiritual experiences, religious faith and coping, and community observer ratings. The enduring trait-level increases in prosocial attitudes and healthy psychological functioning were linked to the mystical-type experience occasioned by psilocybin and the rate of meditation or spiritual practices.
Current Drug Abuse Reviews
January 9, 2015
Albert Garcia‐romeu, Roland R. Griffiths, Matthew W. Johnson
480 citations
In an open-label pilot study, 15 smokers received 2 or 3 doses of psilocybin alongside cognitive behavioral therapy for smoking cessation. Twelve of 15 participants (80%) had biologically verified smoking abstinence at 6-month follow-up. Those who quit scored significantly higher on a measure of psilocybin-occasioned mystical experience than those who relapsed, while general drug intensity did not differ between groups. Nine of 15 participants (60%) met criteria for a complete mystical experience. Smoking cessation outcomes correlated with measures of mystical experience on session days and with retrospective ratings of personal meaning and spiritual significance. The results suggest mystical experience may mediate psychedelic-facilitated addiction treatment.
Journal of Psychopharmacology
February 1, 2022
Natalie Gukasyan, Alan K. Davis, Frederick S. Barrett et al.
419 citations
In patients with moderate to severe major depressive disorder, psilocybin-assisted therapy produced large and sustained decreases in depression severity through 12 months. Scores on the GRID-Hamilton Depression Rating Scale dropped substantially from baseline at 1, 3, 6, and 12 months (effect sizes of 2.3, 2.0, 2.6, and 2.4, respectively). At 12 months, 75% of participants showed a 50% or greater reduction in symptoms and 58% achieved remission. No serious adverse events linked to psilocybin occurred during long-term follow-up, and no participants used psilocybin outside the study. Ratings of personal meaning, spiritual experience, and mystical experience after sessions predicted greater well-being at 12 months but did not predict depression improvement.
Journal for the Scientific Study of Religion
December 1, 2012
Katherine A. Maclean, Jeannie‐marie Leoutsakos, Matthew W. Johnson et al.
412 citations
A 30-item version of the Mystical Experience Questionnaire (MEQ) reliably measures four core dimensions of mystical experiences brought on by psilocybin: unity, noetic quality, and sacredness; positive mood; transcendence of time and space; and ineffability. Over 1,600 participants who had taken psilocybin completed the original 43-item MEQ, and factor analysis retained 30 items with a clear four-factor structure. Those who reported having a mystical experience scored significantly higher on all factors, confirming the scale's construct validity. The factor structure held in a second sample of 440 people and fit better than alternative models, supporting the MEQ's use in scientific studies of hallucinogen-occasioned mysticism.
Journal of contextual behavioral science
January 1, 2020
Alan K. Davis, Frederick S. Barrett, Roland R. Griffiths
369 citations
Acute subjective effects of psychedelics, particularly mystical and insightful experiences, are linked to reductions in depression and anxiety. In a cross-sectional survey of 985 people who had used a psychedelic, increases in psychological flexibility fully mediated the relationship between these acute effects and decreases in depression and anxiety. This suggests that psychological flexibility may be a key mechanism through which psychedelics produce therapeutic benefits. Future prospective studies are needed to test this directly.
Journal of Psychopharmacology
November 18, 2016
Frederick S. Barrett, Matthew P. Bradstreet, Jeannie‐marie Leoutsakos et al.
364 citations
A questionnaire was developed and validated to measure challenging psychological reactions to the hallucinogen psilocybin, often called 'bad trips.' Seven factors emerged: grief, fear, death, insanity, isolation, physical distress, and paranoia. These factors were linked to how difficult, meaningful, spiritually significant, and impactful on well-being participants rated their experiences. The factor structure was consistent regardless of gender or prior struggles with anxiety or depression. The questionnaire offers a tool for studying predictors and outcomes of such challenging experiences.
Neuropharmacology
June 5, 2018
Matthew W. Johnson, Roland R. Griffiths, Peter S. Hendricks et al.
348 citations
Psilocybin, like other classic psychedelics that activate 5-HT2A receptors, has limited reinforcing effects and only marginal, transient non-human self-administration, indicating low abuse potential. Illicit use of psilocybin-containing mushrooms is occasional, with a few lifetime uses being typical. Potential harms include dangerous behavior in unprepared, unsupervised users and exacerbation of mental illness in those predisposed to psychotic disorders, but the scope of use and associated harms are low compared to prototypical abused drugs. The medical model mitigates these risks through dose control, patient screening, preparation, follow-up, and session supervision. If approved as a medicine, the review suggests that Schedule IV placement under the US Controlled Substances Act may be appropriate.
Neurotherapeutics
July 1, 2017
Matthew W. Johnson, Roland R. Griffiths
301 citations
Psilocybin, a classic psychedelic, has shown promise in treating mood and anxiety disorders, particularly in cancer-related psychiatric distress. Three controlled trials found that a single dose may decrease depression and anxiety symptoms for at least six months. An open-label study in treatment-resistant depression reported reduced symptoms three months after two doses. Pilot studies also indicate potential for treating tobacco and alcohol addiction. These trials, involving careful screening and monitoring, report no severe drug-related adverse reactions, with manageable mild effects. US federal funding has not yet supported this research, which is needed to further investigate efficacy and safety.
Journal of Psychopharmacology
June 25, 2018
Tehseen Noorani, Albert Garcia‐romeu, Thomas Cody Swift et al.
285 citations
In a follow-up study of a psilocybin-facilitated smoking cessation pilot, 12 of 15 original participants were interviewed about 30 months after their psilocybin sessions. Participants described gaining vivid insights into their self-identity and reasons for smoking, and reported that experiences of interconnectedness, awe, and curiosity persisted long after the drug's acute effects. The content of the psilocybin experience overshadowed short-term withdrawal symptoms. Participants also emphasized the importance of preparatory counseling, strong rapport with the study team, and a sense of momentum from being engaged in the treatment. Beyond quitting smoking, many reported lasting positive changes such as increased aesthetic appreciation, altruism, and pro-social behavior.
Curr Top Behav Neurosci
January 1, 2018
Frederick S. Barrett, Roland R. Griffiths
268 citations
Mystical-type experiences, historically linked to classic hallucinogens, can be reliably measured with a validated questionnaire. Under double-blind conditions controlling for expectancy, psilocybin produces complete mystical experiences in most people, with effects that are dose-dependent and specific compared to placebo or an active control. These experiences have lasting positive impacts on mood, attitudes, and behavior, as reported by participants and community observers. In healthy volunteers, they generate enduring personal meaning; in patients, they are associated with reduced substance abuse and decreased anxiety and depression, including in those with life-threatening cancer. Parallels in brain activity between hallucinogens and meditative practices suggest a neural model based on changes in the default mode network.
PLoS ONE
April 23, 2019
Roland R. Griffiths, Ethan Hurwitz, Alan K. Davis et al.
249 citations
Experiences interpreted as personal encounters with God, whether occurring naturally or after taking psychedelic drugs, share striking similarities. In an online survey of over 4,200 people, those who had a nondrug encounter most often called it God, whereas those who had a psychedelic encounter most often called it Ultimate Reality. Regardless of origin, most participants vividly remembered the encounter as involving a conscious, benevolent, intelligent, sacred, eternal, and all-knowing presence. About half of all encounters met criteria for a complete mystical experience. More than two-thirds of self-identified atheists no longer identified as atheist afterward.
Frontiers in Psychiatry
January 22, 2020
Earth Erowid, Fire Erowid, Albert Garcia‐romeu et al.
155 citations
A cross-sectional, self-report survey found that people who use psychedelics reported reductions in problematic substance use, including alcohol, opioids, and stimulants. The authors note that because the study is cross-sectional and relies on self-reports, it cannot determine whether psychedelics caused these changes. However, the results suggest a potential for psychedelics to reduce problematic substance use and support further clinical research into psychedelic-assisted treatment for substance use disorders.
JAMA Psychiatry
October 1, 2022
David B. Yaden, James B. Potash, Roland R. Griffiths
153 citations
Public perception of psychedelics has swung from extreme stigma to uncritical enthusiasm, creating obstacles for clinical application. This viewpoint argues that both poles are problematic and advocates for continued scientific study while encouraging critical examination of claims not supported by evidence. The authors call for a balanced approach that neither dismisses therapeutic potential nor overpromises benefits, emphasizing the need for rigorous research to guide responsible clinical integration.
Journal of Psychopharmacology
January 18, 2017
Matthew W. Johnson, Albert Garcia‐romeu, Patrick S. Johnson et al.
129 citations
A survey of 358 people who quit or reduced smoking after using a psychedelic (like psilocybin or LSD) in a non-laboratory setting at least one year earlier found that 38% reported continuous smoking cessation, with 74% of those abstinent for over two years. Another 28% reported a lasting reduction in smoking, from a median of 300 cigarettes per month before to 1 per month after. The remaining 34% temporarily reduced smoking but relapsed, typically within 3–6 months. Those who relapsed rated their psychedelic experience as less personally meaningful and spiritually significant than the other groups. Across all groups, participants reported less severe withdrawal symptoms like depression and craving after psychedelic use compared with past quit attempts. Changes in life priorities and values were cited as the most important psychological factor.
JAMA Psychiatry
May 1, 2021
David B. Yaden, Mary E. Yaden, Roland R. Griffiths
102 citations
No Summary
Journal of Psychopharmacology
February 20, 2021
Albert Garcia‐romeu, Frederick S. Barrett, Theresa M. Carbonaro et al.
101 citations
Psilocybin, a naturally occurring psychedelic, shows promise for treating mood and substance use disorders when given in structured settings. Most trials have adjusted the dose by body weight, but fixed dosing is simpler and cheaper. Analyzing data from ten previous studies (total 288 participants) that used weight-adjusted doses of 20 or 30 mg per 70 kg, or a fixed dose approximating 25 mg, no significant associations emerged between body weight or sex and the subjective effects (mystical, challenging, or intensity). Across body weights from 49 to 113 kg, body weight did not affect psilocybin's subjective effects, suggesting fixed dosing is as effective and more practical than weight-adjusted dosing.
Frontiers in Psychiatry
September 19, 2023
Hillary Jackson, Sara So, Abigail Yaffe et al.
87 citations
A large prospective survey of adults planning to take psilocybin outside clinical settings found that, on average, participants reported lasting reductions in anxiety, depression, and alcohol misuse, along with improvements in cognitive flexibility, emotion regulation, spiritual wellbeing, and extraversion, and decreases in neuroticism and burnout after use. However, a minority reported persisting negative effects: 11% at 2–4 weeks and 7% at 2–3 months after use, including mood fluctuations and depressive symptoms. The study included 2,833 respondents at baseline, 1,182 at 2–4 weeks, and 657 at 2–3 months post-use. Participants were primarily college-educated White men in the United States, mean age 40, who used dried psilocybin mushrooms (mean dose 3.1 grams) for self-exploration.
Frontiers in Psychology
December 6, 2018
Rafael Lancelotta, Austin-Marley Windham-Herman, Kristel Peterson et al.
80 citations
Vaporized 5-MeO-DMT, a psychoactive substance from the Colorado River Toad, reliably produced strong mystical experiences in 20 individuals at a psychospiritual retreat. Participants received 50 mg of inhaled bufotoxin and completed the Mystical Experience Questionnaire. The average intensity was 4.17 out of 5, and 75% had a complete mystical experience. Compared to a prior psilocybin study, 5-MeO-DMT matched the intensity of a high dose (30 mg/70 kg) of psilocybin and significantly exceeded a moderate/high dose (20 mg/70 kg). The short duration may benefit clinical interventions and research on mystical-type experiences.