Editing Psilocybin (section)

==Effects==
[[File:Timothy-Leary-Los-Angeles-1989.jpg|thumb|American psychologist and [[Counterculture of the 1960s|counterculture]] figure [[Timothy Leary]] conducted early experiments into the effects of psychedelic drugs, including psilocybin (1989 photo).]]

Psilocybin produces a variety of [[psychological]], [[perceptual]], [[interpersonal]], and [[physiological|physical]] effects.<ref name="HolzeSinghLiechti2024" />

===Psychological and perceptual effects===
[[File:Prefrontal cortex.png|thumb|The ability of psilocybin to cause perceptual distortions is linked to its influence on the activity of the [[prefrontal cortex]].]]

After ingesting psilocybin, the user may experience a wide range of emotional effects, which can include disorientation, lethargy, giddiness, [[euphoria]], joy, and [[depression (mood)|depression]]. In one study, 31% of volunteers given a high dose reported feelings of significant fear and 17% experienced transient [[paranoia]].<ref name=Amsterdam2011/> In studies at [[Johns Hopkins University|Johns Hopkins]], among those given a moderate dose (but enough to "give a high probability of a profound and beneficial experience"), negative experiences were rare, whereas one-third of those given a high dose experienced anxiety or paranoia.<ref>{{Cite news |date=December 1, 2016 |title=Hallucinogenic Drug Psilocybin Eases Existential Anxiety in People With Life-Threatening Cancer |url=https://www.hopkinsmedicine.org/news/media/releases/hallucinogenic_drug_psilocybin_eases_existential_anxiety_in_people_with_life_threatening_cancer |url-status=live |archive-url=https://web.archive.org/web/20210407123910/https://www.hopkinsmedicine.org/news/media/releases/hallucinogenic_drug_psilocybin_eases_existential_anxiety_in_people_with_life_threatening_cancer |archive-date=April 7, 2021 |access-date=April 9, 2019 |publisher=Johns Hopkins}}</ref><ref name="Hopkins2011">{{cite journal | vauthors = Griffiths RR, Johnson MW, Richards WA, Richards BD, McCann U, Jesse R | title = Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects | journal = Psychopharmacology | volume = 218 | issue = 4 | pages = 649–665 | date = December 2011 | pmid = 21674151 | pmc = 3308357 | doi = 10.1007/s00213-011-2358-5 }}</ref> Low doses can induce hallucinatory effects. [[Closed-eye hallucination]]s may occur, where the affected person sees multicolored geometric shapes and vivid imaginative sequences.<ref name="HaslerGrimbergBenz2004" /> Some people report [[synesthesia]], such as tactile sensations when viewing colors.<ref name="Ballesteros_2006">{{Cite book |title=New Research on Street Drugs |vauthors=Ballesteros S, Ramón MF, Iturralde MJ, Martínez-Arrieta R |publisher=[[Nova Science Publishers]] |year=2006 |isbn=978-1-59454-961-8 |veditors=Cole SM |location=New York, New York |pages=167–186 |chapter=Natural sources of drugs of abuse: magic mushrooms |access-date=February 27, 2016 |chapter-url=https://books.google.com/books?id=ovGcMmz5emUC&pg=PA167 |archive-url=https://web.archive.org/web/20170404021804/https://books.google.com/books?id=ovGcMmz5emUC&pg=PA167 |archive-date=April 4, 2017 |url-status=live}}</ref>{{rp|175}} At higher doses, psilocybin can lead to "intensification of affective responses, enhanced ability for introspection, regression to primitive and childlike thinking, and activation of vivid memory traces with pronounced emotional undertones".<ref name=Studerus2011/> Open-eye visual hallucinations are common and may be very detailed, although [[Pseudohallucination|rarely confused with reality.]]<ref name="HaslerGrimbergBenz2004" />

Psilocybin is known to strongly affect the subjective experience of the [[time perception|passage of time]].<ref name="Heimann1994">{{Cite book |title=50 Years of LSD. Current Status and Perspectives of Hallucinogens |vauthors=Heimann H |publisher=The Parthenon Publishing Group |year=1994 |isbn=978-1-85070-569-7 |veditors=Pletscher A, Ladewig D |location=New York, New York |pages=59–66 |chapter=Experience of time and space in model psychoses}}</ref><ref name=":1" /> Users often feel as if time is slowed down, resulting in the perception that "minutes appear to be hours" or "time is standing still".<ref name=Wittmann2007/> Studies have demonstrated that psilocybin significantly impairs subjects' ability to gauge time intervals longer than 2.5 seconds, impairs their ability to synchronize to inter-beat intervals longer than 2 seconds, and reduces their preferred [[tapping rate]].<ref name=Wittmann2007/><ref name=Wackermann2008/> These results are consistent with the drug's role in affecting [[prefrontal cortex]] activity<ref name=Carter2005/> and the role that the prefrontal cortex plays in time perception,<ref name=Harrington1999/> but the neurochemical basis of psilocybin's effects on perception of time is not known with certainty.<ref name=Coull2011/>

Users having a pleasant experience can feel a sense of connection to others, nature, and the universe; other perceptions and emotions are also often intensified. Users having an unpleasant experience (a "[[bad trip]]") describe a reaction accompanied by fear, other unpleasant feelings, and occasionally by dangerous behavior. The term "bad trip" is generally used to describe a reaction characterized primarily by fear or other unpleasant emotions, not just a transitory experience of such feelings. A variety of factors may contribute to a bad trip, including "tripping" during an emotional or physical low or in a non-supportive environment (see: [[set and setting]]). Ingesting psilocybin in combination with other drugs, including [[alcohol (drug)|alcohol]], can also increase the likelihood of a bad trip.<ref name=Amsterdam2011/><ref name=Attema2007/> Other than the duration of the experience, the effects of psilocybin are similar to comparable dosages of [[lysergic acid diethylamide]] (LSD) or [[mescaline]]. But in the ''Psychedelics Encyclopedia'', author [[Peter Stafford]] writes: "The psilocybin experience seems to be warmer, not as forceful and less isolating. It tends to build connections between people, who are generally much more in communication than when they use LSD."<ref name=Stafford1992>{{Cite book |title=Psychedelics Encyclopedia |vauthors=Stafford PJ |publisher=Ronin Publishing |year=1992 |isbn=978-0-914171-51-5 |edition=3rd |location=Berkeley, California |author-link=Peter Stafford}}</ref>{{rp|273}}

====Set and setting and moderating factors====
The effects of psilocybin are highly variable and depend on the mindset and environment in which the user has the experience. factors commonly called [[set and setting]]. In the early 1960s, [[Timothy Leary]] and his Harvard colleagues investigated the role of set and setting in psilocybin's effects. They administered the drug to 175 volunteers (from various backgrounds) in an environment intended to be similar to a comfortable living room. 98 of the subjects were given questionnaires to assess their experiences and the contribution of background and situational factors. Those who had prior experience with psilocybin reported more pleasant experiences than those for whom the drug was novel. Group size, dosage, preparation, and expectancy were important determinants of the drug response. In general, those in groups of more than eight felt that the groups were less supportive and their experiences less pleasant. Conversely, smaller groups (fewer than six) were seen as more supportive and reported more positive reactions to the drug in those groups. Leary and colleagues proposed that psilocybin heightens suggestibility, making a user more receptive to interpersonal interactions and environmental stimuli.<ref name=Leary1963/> These findings were affirmed in a later review by Jos ten Berge (1999), who concluded that dosage, set, and setting are fundamental factors in determining the outcome of experiments that tested the effects of psychedelic drugs on artists' creativity.<ref name=Berge1999/>

====Theory of mind network and default mode network====
Psychedelics, including psilocybin, have been shown to affect different clusters of brain regions known as the "theory of mind network" (ToMN) and the [[default mode network]] (DMN).<ref name=":0">{{cite journal | vauthors = Soares C, Gonzalo G, Castelhano J, Castelo-Branco M | title = The relationship between the default mode network and the theory of mind network as revealed by psychedelics - A meta-analysis | journal = Neuroscience and Biobehavioral Reviews | volume = 152 | pages = 105325 | date = September 2023 | pmid = 37467907 | doi = 10.1016/j.neubiorev.2023.105325 | doi-access = free }}</ref> The ToMN involves making inferences and understanding social situations based on patterns<ref>{{cite journal | vauthors = Theriault J, Waytz A, Heiphetz L, Young L | title = Theory of mind network activity is associated with metaethical judgment: An item analysis | journal = Neuropsychologia | volume = 143 | pages = 107475 | date = June 2020 | pmid = 32360298 | doi = 10.1016/j.neuropsychologia.2020.107475 }}</ref> whereas, the DMN relates more to introspection and one's sense of self.<ref name=":0" /> The DMN in particular is related to increased rumination and worsening self-image in patients with major depressive disorder (MDD).<ref>{{cite journal | vauthors = Chou T, Deckersbach T, Dougherty DD, Hooley JM | title = The default mode network and rumination in individuals at risk for depression | journal = Social Cognitive and Affective Neuroscience | volume = 18 | issue = 1 | pages = nsad032 | date = June 2023 | pmid = 37261927 | pmc = 10634292 | doi = 10.1093/scan/nsad032 }}</ref> In studies done with single use psilocybin, areas of the DMN showed decreased functional connectivity (communication between areas of the brain). This provides functional insight into the work of psilocybin in increasing one's sense of connection to one's surroundings, as the areas of the brain involved in introspection decrease in functionality under the effects of the drug.<ref>{{cite journal | vauthors = Gattuso JJ, Perkins D, Ruffell S, Lawrence AJ, Hoyer D, Jacobson LH, Timmermann C, Castle D, Rossell SL, Downey LA, Pagni BA, Galvão-Coelho NL, Nutt D, Sarris J | title = Default Mode Network Modulation by Psychedelics: A Systematic Review | journal = The International Journal of Neuropsychopharmacology | volume = 26 | issue = 3 | pages = 155–188 | date = March 2023 | pmid = 36272145 | pmc = 10032309 | doi = 10.1093/ijnp/pyac074 | author-link9 = Susan Rossell }}</ref> Conversely, areas of the brain involved in the ToMN showed increased activity and functional activation in response to psychedelics. These results were not unique to psilocybin and there was no significant difference in brain activation found in similar trials of mescaline and LSD. Information and studies into the DMN and ToMN are relatively sparse and their connections to other psychiatric illnesses and the use of psychedelics is still largely unknown.<ref name=":0" />

====Group perceptions====
Through further [[anthropological]] studies regarding "personal insights"<ref>{{Cite web |title=Drug Addictions, Hallucinogens and Shamanism: the View from Anthropology - Document - Gale Academic OneFile<!-- Bot generated title --> |url=https://go.gale.com/ps/i.do?id=GALE%7CA76445692&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=15254283&p=AONE&sw=w&userGroupName=anon%7Ef134fbbe |url-status=live |archive-url=https://web.archive.org/web/20210823013553/https://go.gale.com/ps/i.do?id=GALE%7CA76445692&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=15254283&p=AONE&sw=w&userGroupName=anon~f134fbbe |archive-date=August 23, 2021 |access-date=August 23, 2021}}</ref> and the psychosocial effects of psilocybin, it can be seen in many traditional societies that powerful mind-active substances such as psilocybin are regularly "consumed ritually for therapeutic purposes or for transcending normal, everyday reality".<ref name="Batchelder_2001">{{Cite journal |vauthors=Batchelder T |date=2001 |title=Drug Addictions, Hallucinogens and Shamanism: the View from Anthropology |url=https://link.gale.com/apps/doc/A76445692/AONE?u=anon~f134fbbe&sid=googleScholar&xid=67117c36 |url-status=live |journal=Drug Addictions, Hallucinogens and Shamanism |series=Townsend Letter for Doctors and Patients |volume=217 |pages=74–77 |archive-url=https://web.archive.org/web/20211019195214/https://go.gale.com/ps/i.do?p=AONE&u=anon~f134fbbe&id=GALE%7CA76445692&v=2.1&it=r&sid=googleScholar&asid=67117c36 |archive-date=October 19, 2021 |access-date=August 23, 2021 |via=Gale Academic OneFile}}</ref> Positive effects that psilocybin has on individuals can be observed by taking on an anthropological approach and moving away from the Western biomedical view; this is aided by the studies done by Leary.<ref>{{Cite book |url=https://www.worldcat.org/oclc/318713242 |title=The psychedelic experience : a manual based on the Tibetan book of the dead |vauthors=Leary T |date=2007 |publisher=Citadel Press |others=Ralph Metzner, Ram Dass, activeth century Karma-gliṅ-pa |isbn=978-0-8065-1652-3 |location=New York |oclc=318713242 |access-date=August 23, 2021 |archive-url=https://web.archive.org/web/20211019195234/https://www.worldcat.org/title/psychedelic-experience-a-manual-based-on-the-tibetan-book-of-the-dead/oclc/318713242 |archive-date=October 19, 2021 |url-status=live}}</ref> Within certain traditional societies, where the use of psilocybin is frequent for shamanic healing rituals, group collectives praise their guide, healer and shaman for helping alleviate their pains, aches and hurt. They do this through a group ritual practice where the group, or just the guide, ingests psilocybin to help extract any "toxic psychic residues or sorcerous implants"<ref name="Batchelder_2001" /> found in one's body.

Group therapies using "classic" psychedelics are becoming more commonly used in the Western world in clinical practice.<ref>{{cite journal | vauthors = Dos Santos RG, Bouso JC, Rocha JM, Rossi GN, Hallak JE | title = The Use of Classic Hallucinogens/Psychedelics in a Therapeutic Context: Healthcare Policy Opportunities and Challenges | journal = Risk Management and Healthcare Policy | volume = 14 | pages = 901–910 | date = 2024-04-24 | pmid = 33707976 | pmc = 7943545 | doi = 10.2147/RMHP.S300656 | doi-access = free }}</ref> This is speculated to grow, provided the evidence remains indicative of their safety and efficacy.<ref>{{cite journal | vauthors = Hendricks PS | title = Psilocybin-assisted group therapy: A new hope for demoralization | journal = eClinicalMedicine | volume = 27 | pages = 100557 | date = October 2020 | pmid = 33073220 | pmc = 7549063 | doi = 10.1016/j.eclinm.2020.100557 }}</ref> In social sense, the group is shaped by their experiences surrounding psilocybin and how they view the fungus collectively. As mentioned in the anthropology article,<ref name="Batchelder_2001" /> the group partakes in a "journey" together, thus adding to the spiritual, social body where roles, hierarchies and gender are subjectively understood.<ref name="Batchelder_2001" />

====Cultural significance and "mystical" experiences====
[[File:Johns Hopkins psilocybin session room-SessionRm 2176x.jpg|thumb|In their studies on the psilocybin experience, Johns Hopkins researchers use peaceful music and a comfortable room to help ensure a comfortable setting, and experienced guides to monitor and reassure the volunteers.]]

Psilocybin mushrooms have been and continue to be used in [[Indigenous peoples of the Americas|Indigenous American]] cultures in religious, [[divinatory]], or [[spirituality|spiritual]] contexts. Reflecting the meaning of the word ''[[entheogen]]'' ("the god within"), the mushrooms are revered as powerful spiritual [[sacrament]]s that provide access to sacred worlds. Typically used in small group community settings, they enhance [[group cohesion]] and reaffirm traditional values.<ref name=Winkelman2007/> [[Terence McKenna]] documented the worldwide practices of psilocybin mushroom usage as part of a cultural [[ethos]] relating to the Earth and mysteries of nature, and suggested that mushrooms enhanced [[self-awareness]] and a sense of contact with a "Transcendent Other"—reflecting a deeper understanding of our connectedness with nature.<ref name=McKenna1992/>

Psychedelic drugs can induce states of [[consciousness]] that have lasting personal meaning and spiritual significance in religious or spiritually inclined people; these states are called [[mystical experience]]s. Some scholars have proposed that many of the qualities of a drug-induced mystical experience are indistinguishable from mystical experiences achieved through [[Religious experience#Causes of religious experiences|non-drug techniques]] such as meditation or [[holotropic breathwork]].<ref name=James1997/><ref name=Metzner1998/> In the 1960s, [[Walter Pahnke]] and colleagues systematically evaluated mystical experiences (which they called "mystical consciousness") by categorizing their common features. According to Pahnke, these categories "describe the core of a universal psychological experience, free from culturally determined philosophical or theological interpretations", and allow researchers to assess mystical experiences on a qualitative, numerical scale.<ref name=Pahnke1969/>

In the 1962 [[Marsh Chapel Experiment]], run by Pahnke at the [[Harvard Divinity School]] under Leary's supervision ,<ref name=Pahnke1966/> almost all the graduate degree [[seminary|divinity]] student volunteers who received psilocybin reported profound religious experiences.<ref name=Griffiths2008/> One of the participants was religious scholar [[Huston Smith]], author of several textbooks on [[comparative religion]]; he called his experience "the most powerful cosmic homecoming I have ever experienced."<ref name=Smith2000/> In a 25-year followup to the experiment, all the subjects given psilocybin said their experience had elements of "a genuine mystical nature and characterized it as one of the high points of their spiritual life".<ref name="Doblin_1991">{{Cite journal |author-link=Rick Doblin |vauthors=Doblin R |year=1991 |title=Pahnke's "Good Friday Experiment": a long-term follow-up and methodological critique |journal=Journal of Transpersonal Psychology |volume=23 |issue=1 |pages=1–25}}</ref>{{rp|13}} Psychedelic researcher [[Rick Doblin]] considered the study partially flawed due to incorrect implementation of the [[double-blind]] procedure and several imprecise questions in the mystical experience questionnaire. Nevertheless, he said that the study cast "considerable doubt on the assertion that mystical experiences catalyzed by drugs are in any way inferior to non-drug mystical experiences in both their immediate content and long-term effects".<ref name="Doblin_1991" />{{rp|24}} Psychiatrist William A. Richards echoed this sentiment, writing in a 2007 review, "[psychedelic] mushroom use may constitute one technology for evoking revelatory experiences that are similar, if not identical, to those that occur through so-called spontaneous alterations of brain chemistry."<ref name=Richards2008/>

A group of researchers from [[Johns Hopkins School of Medicine]] led by [[Roland Griffiths]] conducted a study to assess the immediate and long-term psychological effects of the psilocybin experience, using a modified version of the mystical experience questionnaire and a rigorous double-blind procedure.<ref name=Griffiths2006/> When asked in an interview about the similarity of his work to Leary's, Griffiths explained the difference: "We are conducting rigorous, systematic research with psilocybin under carefully monitored conditions, a route which Dr. Leary abandoned in the early 1960s."<ref name="JHMed: Griffiths Interview" /> Experts have praised the [[National Institute of Drug Abuse]]-funded study, published in 2006, for the soundness of its experimental design.{{efn|The academic communities' approval for the methodology employed is exemplified by the quartet of commentaries published in the journal ''[[Psychopharmacology (journal)|Psychopharmacology]]'' titled "[http://www.hopkinsmedicine.org/Press_releases/2006/GriffithsCommentaries.pdf Commentary on: Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual experience by Griffiths ''et al''.]", by HD Kleber (pp.&nbsp;291–292), DE Nichols (pp.&nbsp;284–286), CR Schuster (pp.&nbsp;289–290), and SH Snyder (pp.&nbsp;287–288).}} In the experiment, 36 volunteers with no experience with hallucinogens were given psilocybin and [[methylphenidate]] (Ritalin) in separate sessions; the methylphenidate sessions served as a [[Scientific control|control]] and psychoactive [[placebo]]. The degree of mystical experience was measured using a questionnaire developed by Ralph W. Hood;<ref name=Hood1975/> 61% of subjects reported a "complete mystical experience" after their psilocybin session, while only 13% reported such an outcome after their experience with methylphenidate. Two months after taking psilocybin, 79% of the participants reported moderately to greatly increased [[life satisfaction]] and sense of well-being. About 36% of participants also had a strong to extreme "experience of fear" or [[dysphoria]] (i.e., a "bad trip") at some point during the psilocybin session (which was not reported by any subject during the methylphenidate session); about one-third of these (13% of the total) reported that this dysphoria dominated the entire session. These negative effects were reported to be easily managed by the researchers and did not have a lasting negative effect on the subject's sense of well-being.<ref name="urlMedical News" />

A follow-up study 14{{nbsp}}months later confirmed that participants continued to attribute deep personal meaning to the experience. Almost a third of the subjects reported that the experience was the single most meaningful or spiritually significant event of their lives, and over two-thirds reported it was among their five most spiritually significant events. About two-thirds said the experience increased their sense of well-being or life satisfaction.<ref name=Griffiths2008/> Even after 14 months, those who reported mystical experiences scored on average 4 percentage points higher on the personality trait of [[Openness to experience|Openness/Intellect]]; personality traits are normally stable across the lifespan for adults. Likewise, in a 2010 web-based questionnaire study designed to investigate user perceptions of the benefits and harms of hallucinogenic drug use, 60% of the 503 psilocybin users reported that their use of psilocybin had a long-term positive impact on their sense of well-being.<ref name=Amsterdam2011/><ref name=CarhartHarris2010/>

While many recent studies have concluded that psilocybin can cause mystical-type experiences of substantial and sustained personal meaning and spiritual significance, the medical community does not unanimously agree. Former director of the Johns Hopkins Department of Psychiatry and Behavioral Science [[Paul R. McHugh]] wrote in a book review: "The unmentioned fact in ''The Harvard Psychedelic Club'' is that LSD, psilocybin, mescaline, and the like produce not a 'higher consciousness' but rather a particular kind of 'lower consciousness' known well to psychiatrists and neurologists—namely, '[[toxic]] [[delirium]].'"<ref>{{Cite web |date=April 1, 2010 |title=Paul McHugh reviews Don Lattin's "The Harvard Psychedelic Club." |url=https://www.commentarymagazine.com/articles/the-harvard-psychedelic-club-by-don-lattin/ |url-status=live |archive-url=https://web.archive.org/web/20190410190600/https://www.commentarymagazine.com/articles/the-harvard-psychedelic-club-by-don-lattin/ |archive-date=April 10, 2019 |access-date=April 10, 2019 |work=commentarymagazine.com}}</ref>

===Physical effects===
Common responses include [[Mydriasis|pupil dilation]] (93%); changes in [[heart rate]] (100%), including increases (56%), decreases (13%), and variable responses (31%); changes in [[blood pressure]] (84%), including [[hypotension]] (34%), [[hypertension]] (28%), and general instability (22%); changes in [[stretch reflex]] (86%), including increases (80%) and decreases (6%); nausea (44%); [[tremor]] (25%); and [[dysmetria]] (16%) (inability to properly direct or limit motions).<ref name="Passie2002" />{{efn|Percentages are derived from a [[Blind experiment#Double-blind trials|non-blind]] clinical study of 30 individuals who were given a dosage of 8–12 milligrams of psilocybin; from Passie (2002),<ref name=Passie2002/> citing Quentin (1960).<ref name=Quentin1960/>}} Psilocybin's [[sympathomimetic]] or [[cardiovascular]] effects, including increased [[heart rate]] and [[blood pressure]], are usually mild.<ref name="FradetKellyDonnelly2025" /><ref name="Passie2002" /> On average, peak heart rate is increased by 5{{nbsp}}bpm, peak [[systolic blood pressure]] by 10 to 15{{nbsp}}mm{{nbsp}}Hg, and peak [[diastolic blood pressure]] by 5 to 10{{nbsp}}mm{{nbsp}}Hg.<ref name="FradetKellyDonnelly2025" /><ref name="Passie2002" /> But temporary increases in blood pressure can be a risk factor for users with preexisting hypertension.<ref name="HaslerGrimbergBenz2004" /> Psilocybin's somatic effects have been corroborated by several early clinical studies.<ref>See for example:

* {{cite journal | vauthors = Isbell H | title = Comparison of the reactions induced by psilocybin and LSD-25 in man | journal = Psychopharmacologia | volume = 1 | issue = 1 | pages = 29–38 | year = 1959 | pmid = 14405870 | doi = 10.1007/BF00408109 | s2cid = 19508675 }}
* {{cite journal | vauthors = Hollister LE, Prusmack JJ, Paulsen A, Rosenquist N | title = Comparison of three psychotropic drugs (psilocybin, JB-329, and IT-290) in volunteer subjects | journal = The Journal of Nervous and Mental Disease | volume = 131 | issue = 5 | pages = 428–434 | date = November 1960 | pmid = 13715375 | doi = 10.1097/00005053-196011000-00007 | s2cid = 8255131 }}
* {{cite journal | vauthors = Malitz S, Esecover H, Wilkens B, Hoch PH | title = Some observations on psilocybin, a new hallucinogen, in volunteer subjects | journal = Comprehensive Psychiatry | volume = 1 | pages = 8–17 | date = February 1960 | pmid = 14420328 | doi = 10.1016/S0010-440X(60)80045-4 }}{{Dead link|date=March 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{cite journal | vauthors = Rinkel M, Atwell CR, Dimascio A, Brown J | title = Experimental psychiatry. V. Psilocybine, a new psychotogenic drug | journal = The New England Journal of Medicine | volume = 262 | issue = 6 | pages = 295–297 | date = February 1960 | pmid = 14437505 | doi = 10.1056/NEJM196002112620606 }}
* {{cite journal | vauthors = Parashos AJ | title = The psilocybin-induced "state of drunkenness" in normal volunteers and schizophrenics | journal = Behavioral Neuropsychiatry | volume = 8 | issue = 1–12 | pages = 83–86 | year = 1976 | pmid = 1052267 }}</ref> A 2005 magazine survey of clubgoers in the UK found that over a quarter of those who had used psilocybin mushrooms in the preceding year experienced nausea or vomiting, although this was caused by the mushroom rather than psilocybin itself.<ref name=Amsterdam2011/> In one study, administration of gradually increasing dosages of psilocybin daily for 21 days had no measurable effect on [[electrolyte]] levels, [[blood sugar]] levels, or [[Liver function tests|liver toxicity tests]].<ref name=Passie2002/>

===Onset and duration===
The [[onset of action]] of psilocybin taken [[oral administration|orally]] is 0.5 to 0.8{{nbsp}}hours (30–50{{nbsp}}minutes) on average, with a range of 0.1 to 1.5{{nbsp}}hours (5–90{{nbsp}}minutes).<ref name="HolzeSinghLiechti2024" /><ref name="MacCallumLoPistawka2022" /> Peak [[psychoactive drug|psychoactive]] effects occur at about 1.0 to 2.2{{nbsp}}hours (60–130{{nbsp}}minutes).<ref name="MacCallumLoPistawka2022" /><ref name="HolzeSinghLiechti2024" /> The [[time to offset]] of psilocybin orally is about 6 to 7{{nbsp}}hours on average.<ref name="HolzeBeckerKolaczynska2023" /> The [[duration of action]] of psilocybin is about 4 to 6{{nbsp}}hours (range 3–12{{nbsp}}hours) orally.<ref name="MacCallumLoPistawka2022" /><ref name="HolzeSinghLiechti2024" /><ref name="YerubandiThomasBhuiya2024">{{cite journal | vauthors = Yerubandi A, Thomas JE, Bhuiya NM, Harrington C, Villa Zapata L, Caballero J | title = Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis | journal = JAMA Network Open | volume = 7 | issue = 4 | pages = e245960 | date = April 2024 | pmid = 38598236 | pmc = 11007582 | doi = 10.1001/jamanetworkopen.2024.5960 | quote = When selecting adverse event profile rates, the shortest time period available was selected and analyzed (eg, day 1 instead of day 30) since the half-life of psilocin is 3 ± 1.1 hours when taken orally and the duration of action can range between 3 to 12 hours.12,13 }}</ref> A small dose of 1{{nbsp}}mg by [[intravenous injection]] had a duration of 15 to 30{{nbsp}}minutes.<ref name="Passie2002" /><ref name="HaslerBourquinBrenneisen1997" />