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PosterTurton S, Carhart-Harris R, Fielding A, et al., 2012,
Intravenously Administered Psilocybin in the fMRI environment - a phenomenological analysis
, British Association for Psychopharmacology Summer MeetingIntroduction: This study aimed to investigate the phenomenology of the perceptual changes caused by the psychedelic agent psilocybin (found in ‘magic mushrooms’)when administered intravenously in a magnetic resonance imaging (MRI) scanner. The subjective effects of psilocybin have been previously documented (Pahnke, 1969,Int Psychiatry Clin 5(4):149-62, Studerus et al, 2011, J Psychopharmacol 25(11):1434-52) however, this provides an opportunity to investigate the effects when psilocybinis administered in a novel manner (intravenous injection) and setting (MRI scanner). Methods: Fifteen healthy volunteers enrolled in a study investigating the brain effectsof intravenous psilocybin using functional MRI (fMRI) imaging (Carhart-Harris et al. 2012, Proc Natl Acad Sci, 109(6):2138-2143). The study consisted of one placeboscan and a second scan during which 2mg of psilocybin were administered intravenously. Following the second fMRI scan participants underwent a semi-structuredinterview, allowing them to describe and elaborate on their experience. These interviews were fi lmed and the content analysed using an interpretative phenomenologicalanalysis methodology. Results: The peak effects of psilocybin lasted between 15-30 minutes. The two phenomenological categories that arose from the analysis consistedof experiences related to the fMRI scanner and the research environment, and experiences related to the perceptual changes caused by the psilocybin. Key componentsrelating to the scanner environment were: the scanner having a negative effect on the experience (n=11), the research environment having a negative effect on theexperience (n=11) diffi culty with the scanner noise (n=10), sense of sensory deprivation (n=8) and preferring a more ‘natural’ environment (n=9). Components relatingto the perceptual changes included visual hallucinations or distortions (n=15), physical sensations (n=12), auditory distortions (n=7), altered time perception (n=13)
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Journal articleCarhart-Harris RL, Leech R, Williams TM, et al., 2012,
Implications for psychedelic-assisted psychotherapy: functional magnetic resonance imaging study with psilocybin
, BRITISH JOURNAL OF PSYCHIATRY, Vol: 200, Pages: 238-244, ISSN: 0007-1250- Author Web Link
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- Citations: 125
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Journal articleCarhart-Harris RL, Erritzoe DE, Williams TM, et al., 2012,
The neural correlates of the psychedelic state as determined by fMRI studies with psilocybin
, Proceedings of the National Academy of Sciences of USAPsychedelic 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 howthey 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 normalwaking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen leveldependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain’s key connector hubs, enabling a state of unconstrained cognition.
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Journal articleCarhart-Harris RL, Williams TM, Sessa B, et al., 2011,
The administration of psilocybin to healthy, hallucinogen-experienced volunteers in a mock-functional magnetic resonance imaging environment: a preliminary investigation of tolerability
, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 25, Pages: 1562-1567, ISSN: 0269-8811- Author Web Link
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- Citations: 30
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Conference paperCarhart-Harris R, Erritzoe D, Stone J, et al., 2011,
The functional brain correlates of the psychedelic state: an arterial spin labelling study with psilocybin
, 24th Congress Meeting of European-College-of-Neuropsychopharmacology, Publisher: ELSEVIER SCIENCE BV, Pages: S313-S313, ISSN: 0924-977X -
Conference paperCarhart-Harris RL, Erritzoe DE, Williams TM, et al., 2011,
DECREASED CEREBRAL BLOOD FLOW AFTER INTRAVENOUS PSILOCYBIN
, Summer Meeting of the British-Association-for-Psychopharmacology, Publisher: SAGE PUBLICATIONS LTD, Pages: A39-A39, ISSN: 0269-8811 -
Conference paperCarhart-Harris RL, Williams TM, Sessa B, et al., 2010,
THE ADMINISTRATION OF PSILOCYBIN TO HEALTHY HALLUCINOGEN-EXPERIENCED VOLUNTEERS IN A MOCK-FMRI ENVIRONMENT: A PRELIMINARY INVESTIGATION OF TOLERABILITY
, Summer Meeting of the British-Association-for-Psychopharmacology, Publisher: SAGE PUBLICATIONS LTD, Pages: A60-A60, ISSN: 0269-8811 -
Journal articleCarhart-Harris RL, Nutt DJ, 2010,
User perceptions of the benefits and harms of hallucinogenic drug use: A web-based questionnaire study
, Journal of Substance Use: for nursing, health and social care, Vol: 15, Pages: 283-300, ISSN: 1357-5007This study used a web-based questionnaire to investigate user perceptions of the benefits and harms of hallucinogenic drug use. Over 600 forms were submitted. Users were asked to comment on the acute and prolonged effects of different drugs and to provide more specific information on how particular drugs have harmed and/or helped them. Subjects reported relatively less harm associated with the classic hallucinogens, LSD and psilocybin, than other drugs specifically focused on in the questionnaire (MDMA, cannabis, ketamine and alcohol). A wide-range of benefits was reported, including: help with mood disorders, addictions and migraine as well as more general long-term improvements in wellbeing. Symptoms of hallucinogen persisting perceptual disorder were reported by a number of subjects and these were most closely associated with use of LSD; however, few users regarded these effects as troubling. Eighty-one per cent of users reported having had a ‘spiritual experience’ on a hallucinogenic drug and over 90% considered ‘access to the unconscious mind’ to be a specific property of the classic hallucinogens. With caution, these findings support recent calls for a systematic investigation of the therapeutic potential of the classic hallucinogens and highlight the scope for empirical investigations of spiritual and psychodynamic phenomena.
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