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Psilocybin

Systematický název	[3-(2-dimethylaminoethyl)-1H-indol-4-yl] dihydrogenfosfát
Registrační číslo CAS	520-52-5
Sumární vzorec	C₁₂H₁₇N₂0₄P₁
Molární hmotnost	284,25 g/mol

Psilocybin je psychedelický indol ze skupiny tryptaminů, obsažený v různých druzích hub, například rodu Psilocybe (lysohlávka), Panaeolus (kropenatec) nebo Gymnopilus (šupinovka). Mnozí uživatelé těchto hub je považují za prostředek k získání náboženské či transcendentní zkušenosti (entheogen) nebo k meditaci.

Obsah

1 Biochemie a toxicita
2 Historie
3 Effects
4 Social and legal aspects
5 See also
6 References
- 6.1 2006 Johns Hopkins experiment
- 6.2 2008 Follow-up to Johns Hopkins experiment
7 External links

[editovat] Biochemie a toxicita

Psilocybin (O-fosforyl-4-hydroxy-N,N-dimethyltryptamin) se v těle v kyselém prostředí účinkem enzymů fosfatáz defosforyluje na farmakologicky účinný psilocin. Ten potom působí jako částečný agonista k receptorům 5-HT2A v mozku, a napodobuje tak působení serotoninu. ^[1] Akutní toxicita psilocybinu je poměrně nízká, orální LD₅₀ u krys je 280 mg/kg, tedy asi poloviční než u kofeinu. Při intravenózním podání králíkům je LD₅₀ asi 12,5 mg/kg. ^[2]

[editovat] Historie

Švýcarský chemik Albert Hofmann, objevitel LSD, byl koncem 50. let minulého století první, kdo z hub izoloval psilocybin i psilocin a určil jejich chemickou strukturu. Sám také poprvé vyzkoušel psychotropní účinky těchto látek na sobě. V roce 1961 zkoušeli američtí psychologové Timothy Leary a Richard Alpert na Harvardově univerzitě psilocybin jako prostředek pro léčbu poruch osobnosti. Psilocybin se stále příležitostně zkoumá např.jako potenciální lék při obsesivně-kompulzivní poruše ^[3] nebo prostředek pro zmírnění utrpení pacientů v terminálních stadiích nádorových onemocnění. ^[4]^[5]^[6] ^[7] Psilocybin jako čistá látka a kontrolovaná susbtance vždy byl a stále je velmi obtížně dostupný. Už od 60. let minulého století proto téměř všichni rekreační uživatelé znají jeho účinky pouze prostřednictvím hub, které ho obsahují.

[editovat] Effects

The effects of psilocybin are highly variable, and dependent on the current mood and overall sense of well-being by the individual. Initially the subject may begin to feel somewhat disorientated, lethargic, and euphoric or sometimes depressed. At low doses, hallucinatory effects may occur, including enhancement of colors and the animation of geometric shapes. Closed-eye hallucination may occur, where the affected individual may see multi-coloured geometric shapes and vivid imaginative sequences. At higher doses, hallucinatory effects increase and experiences tend to be less social and more introspectic or entheogenic. Open-eye visuals are more common, and may be very detailed although rarely confused with reality.

Distortions in the experience of time in psilocybin-induced states have been subjectively reported ^[8], and objectively measured ^[9]. In these studies, psilocybin significantly decreased subjects’ reproduction of time intervals longer than 2.5 s, impaired their ability to synchronize to inter-beat intervals longer than 2 s, and reduced their preferred tapping rate. Recent studies into the effects of psilocybin on time interval reproduction may shed light on qualitative alterations of time experience in experimentally-induced altered states of consciousness, mystical states, or in psychopathology.^[10]

Users having a pleasant experience can feel ecstatic, a sense of connection to others, nature, the universe, and other feelings/emotions are often intensified. Difficult experiences or bad trips occur due to a variety of reasons. Tripping during an emotional/physical low, or in a non-supportive/inadequate/etc. environment (see: set and setting) could possibly cause anxiety or some sort of freak-out. Latent psychological issues may be triggered by the strong emotional components of the experience. ^[11]

Some of these individuals report that they have experienced a 'spiritual' episode. For example, in the Marsh Chapel Experiment, which was run by a graduate student at Harvard Divinity School under the supervision of Timothy Leary, almost all of the graduate degree divinity student volunteers who received psilocybin reported profound religious experiences.

In 2006, a group of researchers from Johns Hopkins School of Medicine led by Roland R Griffiths conducted an experiment assessing the degree of mystical experience and attitudinal effects of the psilocybin experience; this report was published in the journal Psychopharmacology. Thirty-six volunteers without prior experience with hallucinogens were given psilocybin and methylphenidate (Ritalin) in separate sessions, the methylphenidate sessions serving as a control and psychoactive placebo; the tests were double-blind. The degree of mystical experience was measured using a questionnaire on mystical experience developed by Ralph W Hood; 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), with about one-third of these (13% of the total) reporting 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.^[12] Further measures at 14 months after the psilocybin experience confirmed that participants continued to attribute deep personal meaning to the experience. This research was widely covered in the major media outlets.^[13] The research team cautions that if hallucinogens are used in less well supervised settings, the possible fear or anxiety responses could lead to harmful behaviors.^[14] Further studies by this group have investigated the relationship of psilocybin dose to likelihood of mystical experience in healthy volunteers^[15] and whether mystical experiences in volunteers given psilocybin can help with anxiety and poor mood due to cancer.^[16]

In rare cases, psilocybin use can cause Hallucinogen Persisting Perception Disorder. ^[17]

[editovat] Social and legal aspects

Psilocybin and psilocin are listed as Schedule I drugs under the United Nations 1971 Convention on Psychotropic Substances.^[18] Schedule I drugs are illicit drugs that are claimed to have no known therapeutic benefit. Parties to the treaty are required to restrict use of the drug to medical and scientific research under strictly controlled conditions. Most national drug laws have been amended to reflect this convention (for example, the US Psychotropic Substances Act, the UK Misuse of Drugs Act 1971, and the Canadian Controlled Drugs and Substances Act), with possession and use of psilocybin and psilocin being prohibited under almost all circumstances, and often carrying severe legal penalties.

Possession and use of psilocybin mushrooms, including the bluing species of Psilocybe, is therefore prohibited by extension. However, in many national, state, and provincial drug laws, there is a great deal of ambiguity about the legal status of psilocybin mushrooms and the spores of these mushrooms, as well as a strong element of selective enforcement in some places. For more details on the legal status of psilocybin mushrooms and Psilocybe spores, see: Psilocybe: Social and legal aspects.

Because of the ease of cultivating psilocybin mushrooms or gathering wild species, purified psilocybin is often extremely difficult to find on the market.