Nature Medicine
June 3, 2025
Chloé Pronovost-Morgan, Kyle T. Greenway, Leor Roseman et al.
26 citations
Psychedelic substances exhibit complex interactions with the 'set and setting' of use, that is, the mental state of the user and the environment in which a psychedelic experience takes place. Despite these contextual variables' known importance, psychedelic research has lacked methodological rigor in reporting extra-pharmacological factors. This study aimed to generate consensus-based...
Journal of Humanistic Psychology
September 16, 2021
Margo A. Jackson, Joseph G. Ponterotto, Bill Brennan et al.
53 citations
As both 3,4-methylenedioxymethamphetamine (MDMA)- and psilocybin-assisted psychedelic psychotherapy near U.S. Food and Drug Administration (FDA) approval and gain acceptance as efficacious clinical approaches, concerns have been raised about the likelihood of sexual violation of a client and other relational boundary transgressions. In the current study, 23 practitioners who have administered...
Journal of Cognitive Neuroscience
August 1, 2019
Anthony P Zanesco, Brandon G King, Chivon Powers et al.
40 citations
The ability to discriminate among goal-relevant stimuli tends to diminish when detections must be made continuously over time. Previously, we reported that intensive training in shamatha (focused-attention) meditation can improve perceptual discrimination of difficult-to-detect visual stimuli [MacLean, K. A., Ferrer, E., Aichele, S. R., Bridwell, D. A., Zanesco, A. P., Jacobs, T. L., et al....
PLoS One
November 7, 2018
Cassandra Vieten, Helané Wahbeh, B Rael Cahn et al.
124 citations
The science of meditation has grown tremendously in the last two decades. Most studies have focused on evaluating the clinical effectiveness of mindfulness-based interventions, neural and other physiological correlates of meditation, and individual cognitive and emotional aspects of meditation. Far less research has been conducted on more challenging domains to measure, such as group and...
Journal of Psychopharmacology
October 11, 2017
Roland R. Griffiths, Matthew W. Johnson, William A. Richards et al.
528 citations
Psilocybin can occasion mystical-type experiences with participant-attributed increases in well-being. However, little research has examined enduring changes in traits. This study administered psilocybin to participants who undertook a program of meditation/spiritual practices. Healthy participants were randomized to three groups (25 each): (1) very low-dose (1 mg/70 kg on sessions 1 and 2)...
Journal of Psychopharmacology
August 31, 2016
Theresa M. Carbonaro, Matthew P. Bradstreet, Frederick S. Barrett et al.
541 citations
Acute and enduring adverse effects of psilocybin have been reported anecdotally, but have not been well characterized. For this study, 1993 individuals (mean age 30 yrs; 78% male) completed an online survey about their single most psychologically difficult or challenging experience (worst “bad trip”) after consuming psilocybin mushrooms. Thirty-nine percent rated it among the top five most...
Journal of psychopharmacology (Oxford, England)
April 1, 2016
Matthew W Johnson, Katherine A Maclean, Michael J Caspers et al.
11 citations
Salvinorin A is a kappa opioid agonist and the principal psychoactive constituent of the Salvia divinorum plant, which has been used for hallucinogenic effects. Previous research on salvinorin A pharmacokinetics likely underestimated plasma levels typically resulting from the doses administered due to inefficient vaporization and not collecting samples during peak drug effects. Six healthy...
Psychology of Consciousness Theory Research and Practice
March 1, 2016
Anthony P Zanesco, Brandon G King, Katherine A Maclean et al.
61 citations
It is challenging for individuals to maintain their attention on ongoing cognitive tasks without being distracted by task-unrelated thought. The wandering mind is thus a considerable obstacle when attention must be maintained over time. Mental training through meditation has been proposed as an effective method of attenuating the ebb and flow of attention to thoughts and feelings that distract...
Emotion (Washington, D.C.)
December 1, 2015
Erika L Rosenberg, Anthony P Zanesco, Brandon G King et al.
77 citations
Meditation practices purportedly help people develop focused and sustained attention, cultivate feelings of compassionate concern for self and others, and strengthen motivation to help others who are in need. We examined the impact of 3 months of intensive meditative training on emotional responses to scenes of human suffering. Sixty participants were assigned randomly to either a 3-month...
Neuroimage
July 1, 2015
Manish Saggar, Anthony P Zanesco, Brandon G King et al.
31 citations
Meditation training has been shown to enhance attention and improve emotion regulation. However, the brain processes associated with such training are poorly understood and a computational modeling framework is lacking. Modeling approaches that can realistically simulate neurophysiological data while conforming to basic anatomical and physiological constraints can provide a unique opportunity...
PLoS One
2014
Donal G. Maccoon, Katherine A Maclean, Richard J. Davidson et al.
97 citations
Mindfulness Based Stress Reduction (MBSR) is a secular form of meditation training. The vast majority of the extant literature investigating the health effects of mindfulness interventions relies on wait-list control comparisons. Previous studies have found that meditation training over several months is associated with improvements in cognitive control and attention. We used a visual...
Analytical methods : advancing methods and applications
December 21, 2013
Michael J Caspers, Todd D Williams, Kimberly M Lovell et al.
6 citations
A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided...
Health psychology : official journal of the Division of Health Psychology, American Psychological Association
October 1, 2013
Tonya L Jacobs, Phillip R Shaver, Elissa S Epel et al.
62 citations
Cognitive perseverations that include worry and rumination over past or future events may prolong cortisol release, which in turn may contribute to predisease pathways and adversely affect physical health. Meditation training may increase self-reported mindfulness, which has been linked to reductions in cognitive perseverations. However, there are no reports that directly link self-reported...
Psychopharmacology
March 1, 2013
Katherine A Maclean, Matthew W Johnson, Chad J Reissig et al.
134 citations
Salvinorin A is a kappa opioid agonist and the principal psychoactive constituent of the plant Salvia divinorum, which has increased in popularity as a recreational drug over the past decade. Few human studies have examined salvinorin A. This double-blind, placebo-controlled study evaluated the dose-related effects of inhaled salvinorin A in individuals with histories of hallucinogen use. Eight...
Frontiers in Human Neuroscience
2013
Anthony P Zanesco, Brandon G King, Katherine A Maclean et al.
96 citations
Various forms of mental training have been shown to improve performance on cognitively demanding tasks. Individuals trained in meditative practices, for example, show generalized improvements on a variety of tasks assessing attentional performance. A central claim of this training, derived from contemplative traditions, posits that improved attentional performance is accompanied by subjective...
Journal for the Scientific Study of Religion
December 1, 2012
Katherine A Maclean, Jeannie‐marie Leoutsakos, Matthew W. Johnson et al.
412 citations
A large body of historical evidence describes the use of hallucinogenic compounds, such as psilocybin mushrooms, for religious purposes. But few scientific studies have attempted to measure or characterize hallucinogen‐occasioned spiritual experiences. The present study examined the factor structure of the Mystical Experience Questionnaire (MEQ), a self‐report measure that has been used to...
Frontiers in Human Neuroscience
2012
Manish Saggar, Brandon G King, Anthony P Zanesco et al.
136 citations
The capacity to focus one's attention for an extended period of time can be increased through training in contemplative practices. However, the cognitive processes engaged during meditation that support trait changes in cognition are not well characterized. We conducted a longitudinal wait-list controlled study of intensive meditation training. Retreat participants practiced focused attention...
Journal of Psychopharmacology
September 28, 2011
Katherine A Maclean, Matthew W Johnson, Roland R. Griffiths
907 citations
A large body of evidence, including longitudinal analyses of personality change, suggests that core personality traits are predominantly stable after age 30. To our knowledge, no study has demonstrated changes in personality in healthy adults after an experimentally manipulated discrete event. Intriguingly, double-blind controlled studies have shown that the classic hallucinogen psilocybin...
Psychoneuroendocrinology
June 1, 2011
Tonya L Jacobs, Elissa S Epel, Jue Lin et al.
435 citations
Telomerase activity is a predictor of long-term cellular viability, which decreases with chronic psychological distress (Epel et al., 2004). Buddhist traditions claim that meditation decreases psychological distress and promotes well-being (e.g., Dalai Lama and Cutler, 2009). Therefore, we investigated the effects of a 3-month meditation retreat on telomerase activity and two major contributors...
Drug and Alcohol Dependence
May 1, 2011
Matthew W Johnson, Katherine A Maclean, Chad J Reissig et al.
134 citations
Salvinorin A is a potent, selective nonnitrogenous kappa opioid agonist and the known psychoactive constituent of Salvia divinorum, a member of the mint family that has been used for centuries by Mazatec shamans of Mexico for divination and spiritual healing. S. divinorum has over the last several years gained increased popularity as a recreational drug. This is a double-blind, placebo...
Emotion (Washington, D.C.)
April 1, 2011
Baljinder K Sahdra, Katherine A Maclean, Emilio Ferrer et al.
203 citations
We examined the impact of training-induced improvements in self-regulation, operationalized in terms of response inhibition, on longitudinal changes in self-reported adaptive socioemotional functioning. Data were collected from participants undergoing 3 months of intensive meditation training in an isolated retreat setting (Retreat 1) and a wait-list control group that later underwent identical...
Psychological Science
June 1, 2010
Katherine A Maclean, Emilio Ferrer, Stephen R Aichele et al.
625 citations
The ability to focus one's attention underlies success in many everyday tasks, but voluntary attention cannot be sustained for extended periods of time. In the laboratory, sustained-attention failure is manifest as a decline in perceptual sensitivity with increasing time on task, known as the vigilance decrement. We investigated improvements in sustained attention with training (approximately 5...
BMC Neurosci
2010
Manish Saggar, Stephen R Aichele, Tonya L Jacobs et al.
50 citations
A computational approach to understanding the longitudinal changes in cortical activity associated with intensive meditation training
Anthony Paul Zanesco, Brandon G King, Chivon Powers et al.
20 citations
The ability to discriminate among goal-relevant stimuli tends to diminish when detections must be made continuously over time. Previously, we reported that intensive training in shamatha (focused-attention) meditation can improve perceptual discrimination of difficult-to-detect visual stimuli (MacLean et al., 2010). Here we extend these findings to examine how discrimination difficulty and...
Donal G. Maccoon, Katherine A Maclean, Richard J. Davidson et al.
9 citations
Background: Mindfulness Based Stress Reduction (MBSR) is a secular form of meditation training. The vast majority of the extant literature investigating the health effects of mindfulness interventions relies on wait-list control comparisons. Previous studies have found that meditation training over several months is associated with improvements in cognitive control and...