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.
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.
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 Humanistic Psychology
September 16, 2021
Margo A. Jackson, Joseph G. Ponterotto, Bill Brennan et al.
53 citations
Practitioners who have administered MDMA and psilocybin in underground (extralegal) healing contexts face unique relational ethical challenges, including client nudity, the use of touch, and the belief that therapists must continue their own psychedelic experiences. Interviews with 23 practitioners revealed descriptive themes of these challenges and prescriptive themes of helpful practices. Some challenges are unique to psychedelic work, while others represent psychedelic-specific takes on standard ethical considerations like transference and supervision. The findings have implications for training psychedelic psychotherapists and regulatory decisions.
Donal G. Maccoon, Katherine A. Maclean, Richard Davidson et al.
9 citations
Eight weeks of mindfulness-based stress reduction (MBSR) training did not improve sustained attention or visual discrimination more than an active control program (Health Enhancement Program) in a randomized trial with 63 community adults. The study had sufficient statistical power to show that the two groups did not differ in their improvement over time on a continuous performance task. One prediction about attentional fatigue was statistically significant but uninterpretable. Some evidence for improved visual discrimination partially replicated earlier findings. Attentional sensitivity appears unaffected by MBSR, but whether mindfulness might benefit vigilance remains unclear.
Drug and Alcohol Dependence
December 16, 2014
Frederick S. Barrett, Matthew P. Bradstreet, Jeannie‐marie Leoutsakos et al.
4 citations
No Summary
Drug and Alcohol Dependence
December 16, 2014
Theresa M. Carbonaro, Frederick S. Barrett, Matthew P. Bradstreet et al.
3 citations
No Summary
Drug and Alcohol Dependence
June 7, 2014
Matthew P. Bradstreet, Matthew W. Johnson, Katherine A. Maclean et al.
1 citation
No Summary
Manish Saggar, Brandon King, Anthony Paul Zanesco et al.
1 citation
Intensive meditation training over three months produces replicable changes in brain electrical activity. Retreat participants who practiced focused attention meditation showed reduced beta-band brain wave power over front and back regions of the scalp during mindfulness of breathing. Individual alpha frequency also decreased across retreats, and the decrease was directly related to the amount of meditation practice. These changes in brain oscillatory patterns may underlie improvements in attention and cognition from contemplative practice.
Anthony Paul Zanesco, Brandon King, Katherine A. Maclean et al.
1 citation
After one month of intensive daily Vipassana meditation training, participants showed improved response inhibition accuracy and reduced reaction time variability on a 32-minute task compared to matched controls. They also reported increased concentration during the task, but not changes in effort or motivation. Critically, the increases in concentration predicted improvements in reaction time variability, linking the subjective experience of concentrative engagement with objective attentional stability. These results corroborate phenomenological accounts from contemplative traditions that meditation training leads to stable, clear attentional engagement, and suggest that meditators' felt experience accurately reflects measurable changes in performance.