{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,9]],"date-time":"2026-11-09T00:21:27Z","timestamp":1794183687982,"version":"4.8.0"},"reference-count":35,"publisher":"SAGE Publications","issue":"11","license":[{"start":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T00:00:00Z","timestamp":1786924800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T00:00:00Z","timestamp":1786924800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["J Psychopharmacol"],"published-print":{"date-parts":[[2026,11]]},"abstract":"\n Humphry Osmond coined the term \u2018psychedelic\u2019 in 1956, conjoining \u2018psyche\u2019 for \u2018soul\u2019 and \u2018delic\u2019 for \u2018to manifest\u2019 or \u2018illuminate\u2019.\n Soul-illumination<\/jats:italic>\n is a compound noun that describes a psychological state or process. Osmond intended for it to be a taxonomic noun\u2014naming, not just a state\u2014but a category of drug that can induce this psychological effect as its principal action. Consistent with the etymology of\n psychedelic<\/jats:italic>\n , the present work respects the fundamental importance of phenomenology. Accordingly, we examine the main subjective effect of three different psychoactive drugs,\n psilocybin<\/jats:italic>\n ,\n ketamine<\/jats:italic>\n , and\n MDMA (3,4-methylenedioxymethamphetamine)<\/jats:italic>\n (variable label,\n Drug<\/jats:italic>\n ). Over 200 participants rated Delphi-generated subjective rating scale items based on their personal experiences with all 3 drugs. Factor analyses revealed three or four sufficiently independent dimensions of subjective experience (variable label,\n Effects<\/jats:italic>\n ). A machine-learning classifier successfully predicted\n Drug<\/jats:italic>\n from\n Effects<\/jats:italic>\n , validating the hypothesis that\n psilocybin<\/jats:italic>\n ,\n ketamine<\/jats:italic>\n and\n MDMA<\/jats:italic>\n have categorically distinct subjective effect profiles, differentiable by (1)\n visions<\/jats:italic>\n and\n psychological insight<\/jats:italic>\n (\n psilocybin<\/jats:italic>\n ), (2)\n dissociation<\/jats:italic>\n (\n ketamine<\/jats:italic>\n ) and (3)\n pro-social<\/jats:italic>\n and\n loving feelings<\/jats:italic>\n (\n MDMA<\/jats:italic>\n ). We conclude that\n psilocybin<\/jats:italic>\n is an exemplar\n psychedelic<\/jats:italic>\n \u2014a category of drug definable by the induction of a\n psychedelic state<\/jats:italic>\n . The quintessential psychedelic phenomenon is a subjective state characterized by\n visions<\/jats:italic>\n and\n psychological insight<\/jats:italic>\n .\n <\/jats:p>","DOI":"10.1177\/02698811261464986","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T08:24:27Z","timestamp":1786955067000},"page":"1760-1770","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Defining \u2018psychedelic\u2019"],"prefix":"10.1177","volume":"40","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6050-7258","authenticated-orcid":false,"given":"A. E.","family":"Ostrand","sequence":"first","affiliation":[{"name":"Carhart-Harris Lab, Department of Neurology, University of California San Francisco, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. M.","family":"Nour","sequence":"additional","affiliation":[{"name":"Department of Psychiatry, University of Oxford, UK"},{"name":"Max Planck UCL Centre for Computational Psychiatry and Ageing Research, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2281-377X","authenticated-orcid":false,"given":"C.","family":"Timmermann","sequence":"additional","affiliation":[{"name":"UCL Centre for Consciousness Research, Department of Experimental Psychology, University College London, UK"},{"name":"Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-1510-6638","authenticated-orcid":false,"given":"A.","family":"Rosati","sequence":"additional","affiliation":[{"name":"Carhart-Harris Lab, Department of Neurology, University of California San Francisco, USA"},{"name":"Department of Psychiatry and Behavioral Sciences, University of California San Francisco, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4773-029X","authenticated-orcid":false,"given":"L. X.","family":"Luan","sequence":"additional","affiliation":[{"name":"Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, UK"},{"name":"Department of Psychology, University of Exeter, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Gomez-Emilsson","sequence":"additional","affiliation":[{"name":"Qualia Research Institute, San Francisco, CA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9168-7877","authenticated-orcid":false,"given":"J.","family":"Bornemann","sequence":"additional","affiliation":[{"name":"Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7829-493X","authenticated-orcid":false,"given":"K. T.","family":"Greenway","sequence":"additional","affiliation":[{"name":"Lady Davis Institute, Jewish General Hospital, Montr\u00e9al, QC, Canada"},{"name":"Department of Psychiatry, Faculty of Medicine, McGill University, Montr\u00e9al, QC, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9990-6029","authenticated-orcid":false,"given":"L.","family":"Roseman","sequence":"additional","affiliation":[{"name":"Department of Psychology, University of Exeter, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6062-7150","authenticated-orcid":false,"given":"Carhart-Harris","family":"R","sequence":"additional","affiliation":[{"name":"Carhart-Harris Lab, Department of Neurology, University of California San Francisco, USA"},{"name":"Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,8,17]]},"reference":[{"key":"e_1_3_3_2_1","doi-asserted-by":"crossref","unstructured":"Acevedo EC Uhler S White KP et al. 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