Journal of Psychopharmacology
2016
Jana Speth, Clemens Speth, Mendel Kaelen et al.
119 citations
This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 μg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured...
Psychopharmacology
November 27, 2015
Joaquim Soler, Matilde Elices, Alba Franquesa et al.
212 citations
BackgroundAyahuasca is a psychotropic plant tea used for ritual purposes by the indigenous populations of the Amazon. In the last two decades, its use has expanded worldwide. The tea contains the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine-oxidase-inhibiting properties. Acute administration induces an introspective dream-like...
Human Brain Mapping
May 22, 2015
Alexander V. Lebedev, Martin Lövdén, Gidon Rosenthal et al.
347 citations
Ego-disturbances have been a topic in schizophrenia research since the earliest clinical descriptions of the disorder. Manifesting as a feeling that one's "self," "ego," or "I" is disintegrating or that the border between one's self and the external world is dissolving, "ego-disintegration" or "dissolution" is also an important feature of the psychedelic experience, such as is produced by...
Frontiers in Human Neuroscience
May 27, 2014
Leor Roseman, Robert Leech, Amanda Feilding et al.
293 citations
Perturbing a system and observing the consequences is a classic scientific strategy for understanding a phenomenon. Psychedelic drugs perturb consciousness in a marked and novel way and thus are powerful tools for studying its mechanisms. In the present analysis, we measured changes in resting-state functional connectivity (RSFC) between a standard template of different independent components...
Biological Psychiatry
January 10, 2014
Robin Carhart-Harris, Kevin Murphy, Robert Leech et al.
182 citations
The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug's characteristic subjective effects arise from its modulation of spontaneous brain activity.
Frontiers in Human Neuroscience
2014
Robin Carhart-Harris, Robert Leech, Peter J. Hellyer et al.
1,289 citations
Entropy is a dimensionless quantity that is used for measuring uncertainty about the state of a system but it can also imply physical qualities, where high entropy is synonymous with high disorder. Entropy is applied here in the context of states of consciousness and their associated neurodynamics, with a particular focus on the psychedelic state. The psychedelic state is considered an exemplar...
The International Journal of Neuropsychopharmacology
December 17, 2013
Robin Carhart-Harris, Matthew B. Wall, David Erritzøe et al.
110 citations
3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine-releaser that is widely used as a recreational drug. Preliminary work has supported the potential of MDMA in psychotherapy for post-traumatic stress disorder (PTSD). The neurobiological mechanisms underlying its putative efficacy are, however, poorly understood. Psychotherapy for PTSD usually requires that patients revisit traumatic...
Journal of Neuroscience
September 18, 2013
Matthew J. Brookes, David Errtizoe, Ben Sessa et al.
501 citations
Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin—prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin...
Schizophrenia Bulletin
October 6, 2012
Robin Carhart-Harris, Robert Leech, David Erritzøe et al.
267 citations
Psilocybin is a classic psychedelic and a candidate drug model of psychosis. This study measured the effects of psilocybin on resting-state network and thalamocortical functional connectivity (FC) using functional magnetic resonance imaging (fMRI). Fifteen healthy volunteers received intravenous infusions of psilocybin and placebo in 2 task-free resting-state scans. Primary analyses focused on...
Journal of Psychopharmacology
October 5, 2012
Amir Englund, Paul D. Morrison, Judith Nottage et al.
463 citations
Community-based studies suggest that cannabis products that are high in Δ⁹-tetrahydrocannabinol (THC) but low in cannabidiol (CBD) are particularly hazardous for mental health. Laboratory-based studies are ideal for clarifying this issue because THC and CBD can be administered in pure form, under controlled conditions. In a between-subjects design, we tested the hypothesis that pre-treatment...
The British Journal of Psychiatry
January 27, 2012
Robin Carhart-Harris, Robert Leech, Tom A. Williams et al.
241 citations
Background Psilocybin is a classic psychedelic drug that has a history of use in psychotherapy. One of the rationales for its use was that it aids emotional insight by lowering psychological defences. Aims To test the hypothesis that psilocybin facilitates access to personal memories and emotions by comparing subjective and neural responses to positive autobiographical memories under psilocybin...
Proceedings of the National Academy of Sciences
January 23, 2012
Alessandro Colasanti, Robin J. Tyacke, Robert Leech et al.
1,191 citations
Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the...
Consciousness and Cognition
January 10, 2012
Gráinne Schäfer, Amanda Feilding, Celia J. A. Morgan et al.
60 citations
Cannabis acutely increases schizotypy and chronic use is associated with elevated rates of psychosis. Creative individuals have higher levels of schizotypy, however links between cannabis use, schizotypy and creativity have not been investigated. We investigated the effects of cannabis smoked naturalistically on schizotypy and divergent thinking, a measure of creativity. One hundred and sixty...
Pharmacopsychiatry
July 22, 2010
James Stone, Paul D. Morrison, Judith Nottage et al.
13 citations
We tested the hypothesis that THC disrupts self-timed actions in healthy volunteers, and that this effect is related to self-rated perceptions of time distortion. We found that THC impaired subjective time perception and reduced the rate of button pressing, although the change in the rate of button pressing was more closely related to impaired concentration and intoxication. We conclude that...
Journal of Psychopharmacology
April 15, 2010
Ben Sessa, Amanda Feilding, Robin Carhart-Harris et al.
53 citations
This study sought to assess the tolerability of intravenously administered psilocybin in healthy, hallucinogen-experienced volunteers in a mock-magnetic resonance imaging environment as a preliminary stage to a controlled investigation using functional magnetic resonance imaging to explore the effects of psilocybin on cerebral blood flow and activity. The present pilot study demonstrated that...