Psilocybin mushrooms

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Be cautious when consuming wild psilocybin mushrooms.

If consuming psilocybin mushrooms harvested in nature, it is important to be aware of the risk of misidentifying and consuming a poisonous look-alike variety. Please see this section for more information.

Summary sheet: Psilocybin mushrooms
Psilocybe cubensis, one of the most common psilocybin-containing mushrooms.

Psilocybin mushrooms (also known as magic mushrooms, psychedelic mushrooms, and shrooms) are a family of psychoactive fungi that contain psilocybin, a psychedelic substance of the tryptamine class. Their effects are thought to be produced by stimulation of serotonin receptors in the brain, although the precise mechanism is not known.

They occur on all continents and have been taxonomically classified into over 200 species, the most potent of which belong to the genus Psilocybe.[1] Based on imagery found in prehistoric rock art, they are thought to have been used by various human cultures since before recorded history. In Mesoamerica, they have been consumed in ritual ceremonies for 3000 years.[2]

Following introduction to American society by Gordon R. Wasson in 1955, they received the attention of clinicians and researchers interested in psychotherapy and mental disorders.[2] Popularization by 1960s counterculture figures like Timothy Leary led to an explosion of recreational use and eventual prohibition in 1970.

Today, they are among the most widely used psychedelic substances (due to the ease of personal cultivation) and the subject of renewed clinical investigation in the areas of anxiety, depression, and other mental disorders.[2]

Subjective effects include open and closed-eye visuals, time distortion, enhanced introspection, conceptual thinking, euphoria, and ego loss. The intensity and duration of effects can vary greatly depending on factors such as species and batch, which can complicate standardized dosing information (see this section). They are often described to evoke entheogenic, mystical-like, or transpersonal experiences that are able to facilitate self-reflection and personal growth.

In distinction to psychedelics like LSD, mescaline, and 2C-B, which may be described as "stimulating", "cerebral", and "bright", psilocybin mushrooms are typically described as having an "earthy", "subliminal", or "dream-like" quality. They also are reported to produce slightly more emotion enhancement, time distortion and ego loss than the aforementioned substances, as well as more nausea and sedation.

Unlike most highly prohibited substances, psilocybin mushrooms have low abuse potential and are neither addictive nor physiologically toxic.[3] However, adverse psychological reactions such as severe anxiety, paranoia, delusions and psychosis are always possible, particularly among individuals predisposed to mental disorders.[4] It is highly advised to use harm reduction practices if using this substance.

History and culture

Cave art in Tassili n'Ajjer, Algeria (look at the shoulders and knees)

A growing body of evidence suggests that psychoactive mushrooms have been used by humans in religious ceremonies for thousands of years.

For example, murals dated 9000 to 7000 BCE found in the Sahara desert in southeast Algeria depict horned beings dressed as dancers holding mushroom-like objects.[5] 6,000-year-old pictographs discovered near the Spanish town of Villar del Humo illustrate several mushrooms that have been tentatively identified as Psilocybe hispanica, a hallucinogenic species native to the area.[6]

Archaeological artifacts from Mexico have also been interpreted by some scholars as evidence for ritual and ceremonial usage of psychoactive mushrooms in the Mayan and Aztec cultures of Mesoamerica.[citation needed] In Nahuatl, the language of the Aztecs, the mushrooms were called teonanácatl, or "God's flesh".

Following the arrival of Spanish explorers to the New World in the 16th century, chroniclers reported the use of mushrooms by the natives for ceremonial and religious purposes. Accounts describe mushrooms being eaten in festivities for the accession of emperors and the celebration of successful business trips by merchants.[7]

After the defeat of the Aztecs, the Spanish forbade traditional religious practices and rituals that they considered "pagan idolatry", including ceremonial mushroom use. For the next four centuries, the Indians of Mesoamerica hid their use of entheogens from the Spanish authorities.[citation needed]

American banker and amateur ethnomycologist R. Gordon Wasson studied the ritual use of psychoactive mushrooms by the native population of a Mazatec village in Mexico. In 1957, Wasson described the psychedelic visions that he experienced during these rituals in "Seeking the Magic Mushroom", an article published in Life magazine.[8] Later that year, they were accompanied on a follow-up expedition by French mycologist Roger Heim, who identified several of the mushrooms as Psilocybe species.[9]

Heim cultivated the mushrooms in France, and sent samples for analysis to Albert Hofmann, a chemist employed by the Swiss pharmaceutical company Sandoz (now Novartis). Hofmann, who had in 1938 created LSD, led a research group that isolated and identified the psychoactive compounds from Psilocybe mexicana.[10][11]

He and his colleagues later synthesized a number of compounds chemically related to the naturally occurring psilocybin, to see how structural changes would affect psychoactivity. These included 4-HO-DET and 4-AcO-DMT. Sandoz marketed and sold pure psilocybin under the name "Indocybin" to clinicians worldwide without any reports of serious complications.[12][13]

In the early 1960s, Harvard University became a testing ground for psilocybin via the efforts of Timothy Leary and his associates, Ralph Metzner and Richard Alpert. Leary obtained synthesized psilocybin from Hofmann through Sandoz. Some studies, such as the Concord Prison Experiment, found promising results for psilocybin's utility in clinical psychiatry.[14][15]

Leary and Alpert's zealous advocacy for widespread hallucinogen use led to a well-publicized termination from Harvard. In response to concerns about the increase in unauthorized use of psychedelic substances by the general public, psychedelics like psilocybin began to receive negative press and faced increasingly restrictive laws.

In the United States, laws were passed in 1966 that prohibited the production, trade, or ingestion of hallucinogenic substances. Sandoz stopped producing LSD and psilocybin the same year.[16] Further backlash against LSD usage swept psilocybin along with it into the Schedule I category of illicit substances in 1970. Subsequent restrictions on the use of these substances in human research made funding for such projects difficult to obtain, and scientists who worked with psychedelic drugs faced being "professionally marginalized".[17]

In the 1990s, psychedelic research gradually began to regain traction, particularly in Europe. Advances in the neurosciences and the availability of brain imaging techniques have provided a reason for using substances like psilocybin to probe the "neural underpinnings of psychotic symptom formation including ego disorders and hallucinations".[18]

Recent studies in the United States have attracted attention from the popular press and thrust psilocybin into the vogue again.[19]

Chemistry

Psilocybin, or 4-phosphoryloxy-N,N-dimethyltryptamine (4-PO-DMT) is a prodrug that is converted into the pharmacologically active compound psilocin in the body by a dephosphorylation reaction mediated by alkaline phosphatase enzymes.[20] Both psilocybin and psilocin are organic tryptamine compounds. They are chemically related to the amino acid tryptophan, and structurally similar to the neurotransmitter serotonin.

Tryptamines share a core structure comprised of a bicyclic indole heterocycle attached at R3 to an amino group via an ethyl side chain. Psilocybin is substituted at R4 of its indole heterocycle with a phosphoryloxy (-PO) functional group. It also contains two methyl groups CH3- bound to the terminal amine RN. This makes psilocybin the 4-phosphoryloxy ring-substituted analog of DMT.[21]

Psilocybin and psilocin occur in their pure forms as white crystalline powders. Both are unstable in light, particularly while in solution, although their stability at low temperatures in the dark under an inert atmosphere is very good.[22]

Pharmacology

The diagram above demonstrates the neural connections associated with sobriety in comparison to being under the influence of psilocybin as demonstrated through the use of MRI scans. The width of the links is proportional to their weight and the size of the nodes is proportional to their strength. Note that the proportion of heavy links between communities is much higher (and very different) in the psilocybin group, suggesting greater integration[23]
Further information: Serotonergic psychedelic

Psilocybin acts as a prodrug to psilocin, meaning it is not active until it is converted into psilocin in the body. Upon entering the body, psilocybin is dephosphorylated to psilocin in the intestinal mucosa by alkaline phosphatase and nonspecific esterase.[2]

Psilocin's psychedelic effects are believed to come from its agonist activity on serotonin 5-HT2A/C and 5-HT1A receptors.[2] While 5-HT2A receptor agonism is considered necessary for hallucinogenic activity, the role of other receptor subtypes is much less understood.[2]

Unlike LSD, psilocin has no significant effect on dopamine receptors and only affects the noradrenergic system at very high dosages.[24]

Psilocybin has also been shown by fMRI imaging to have a dampening effect on certain brain regions, most notably the Default Mode Network.[citation needed]

Subjective effects

The headspace of psilocybin mushrooms is typically described as extremely relaxing, profound and stoning in style compared to more stimulating psychedelics such as LSD or 2C-B. They are also regarded as being less clear-headed than other commonly used tryptamines such as 4-AcO-DMT, DMT and ayahuasca. This may be due to the presence of other alkaloids like norbaeocystin.

Disclaimer: The effects listed below cite the Subjective Effect Index (SEI), an open research literature based on anecdotal user reports and the personal analyses of PsychonautWiki contributors. As a result, they should be viewed with a healthy degree of skepticism.

It is also worth noting that these effects will not necessarily occur in a predictable or reliable manner, although higher doses are more liable to induce the full spectrum of effects. Likewise, adverse effects become increasingly likely with higher doses and may include addiction, severe injury, or death ☠.

Physical effects
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Visual effects
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Cognitive effects
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Multi-sensory effects
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Transpersonal effects
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Combination effects

  • Cannabis - Cannabis majorly amplifies the sensory and cognitive effects of psilocybin mushrooms. This should be used with extreme caution, especially if one is not experienced with psychedelics. This interaction can also amplify the anxiety, confusion and delusion producing aspects of cannabis significantly. Those who choose to use this combination are advised to start off with only a fraction of their usual cannabis dose, and slow down the pace of their normal intake considerably.
  • Dissociatives - Dissociatives can enhance the geometry, euphoria, dissociation and hallucinatory effects of psilocybin mushrooms. Dissociative-induced holes, spaces, and voids while under the influence of psilocybin can result in significantly more vivid visuals than dissociatives alone, along with more intense internal hallucinations, confusion, nausea, delusions and increased risk of psychosis.
  • MDMA - MDMA enhances the visual, physical and cognitive effects of psilocybin. The synergy between these substances is unpredictable, and it is advised to start with lower dosages than one would take for either substance individually. The toxicity of this combination is unknown, although there is some evidence that suggests this may increase the the neurotoxic effects of MDMA.[26][27][28]
  • Alcohol - This combination is not typically recommended due to alcohol’s potential to cause dehydration, nausea, and physical fatigue at higher doses. However, this combination is reasonably safe in low doses and, when used responsibly, can "take the edge off a trip" and reduce anxiety in a manner somewhat similar to benzodiazepines. With psilocybin mushrooms in particular it is often recommended that the user waits until the "come down" phase to consume alcohol due to the sometimes nauseating effects of mushrooms, especially within the first 2 - 3 hours of the experience.
  • Benzodiazepines - Depending on the dosage, benzodiazepines can slightly to completely reduce the intensity of the cognitive, physical and visual effects of a psilocybin trip. They can be very efficient at largely stopping or mitigating a bad trip at the cost of amnesia and reduced trip intensity. Caution is advised when acquiring them for this purpose, however, due to the high abuse potential they possess.
  • Psychedelics - When used in combination with other psychedelics, the physical, cognitive and visual effects of each substance intensify and synergize strongly with each other. The synergy between those substances is unpredictable, and for this reason, is generally not advised. If choosing to combine psychedelics, it is recommended to start with lower dosages than one would take for either substance individually.

Experience reports

There are currently 22 anecdotal reports which describe the effects of this compound within our experience index.

Additional experience reports can be found here:

Dosage and preparation

The dosage of psilocybin mushrooms depends on the potency of the mushroom (the total psilocybin and psilocin content of the mushrooms), which varies significantly both between species and within the same species, but is typically around 0.5–2.0% of the dried weight of the mushroom.[citation needed]

The concentration of active psilocybin mushroom compounds varies not only from species to species, but also from mushroom to mushroom inside a given species, subspecies or variety. The same holds true even for different parts of the same mushroom.

For example, in the species Psilocybe samuiensis, the dried cap of the mushroom contains the most psilocybin at about 0.23%–0.90%. The mycelium contains about 0.24%–0.32%.[29]

Psilocybe cubensis

Psilocybe cubensis (also known as cubes) is one of the most commonly used species of psilocybin mushrooms. The doses for oral consumption for dried cubensis mushrooms are generally considered to be:

  • Threshold: 0.25 g - 0.5 g
  • Light: 0.5 - 1 g
  • Common: 1 - 2.5 g
  • Strong: 2.5 - 5 g
  • Heavy: 5 g +

Preparation methods

Preparation methods for this compound within our tutorial index include:

Natural occurrence

Biological genera containing psilocybin mushrooms include Copelandia, Galerina, Gymnopilus, Inocybe, Mycena, Panaeolus, Pholiotina, Pluteus, and Psilocybe. Over 100 species are classified in the genus Psilocybe.

Some common psilocybin and psilocin containing mushroom species include:

Psilocybe

Psilocybe semilanceata, also known as the liberty cap.

Panaeolus

Panaeolus cyanescens, also known as the pan cyan.
  • Panaeolus africanus
  • Panaeolus campanulatus
  • Panaeolus cinctulus
  • Panaeolus cyanescens
  • Panaeolus subbalteatus
  • Panaeolus venezolanus

Gymnopilus

Gymnopilus luteofolius
  • Gymnopilus aeruginosus
  • Gymnopilus luteofolius
  • Gymnopilus luteus
  • Gymnopilus purpuratus

Dictyonema

  • Dictyonema huaorani (This species is a lichen not a mushroom)

Risk of species confusion

As psilocybin mushrooms are capable of being harvested in nature, there is a major risk in misidentifying the mushroom species and accidentally consuming a poisonous (possibly lethal) variety. This risk can be avoided by educating oneself in advance on how to properly identify the correct species of mushroom and the potential look-alike mushrooms found within one's local area. Users are encouraged to learn from a mentor who is experienced in mushroom picking before doing it on their own.

Research

Antidepressant effects

While further research is needed to establish the utility of psilocybin and other psychedelics in treating depression, a pilot study has observed significantly decreased depression scores in terminal cancer patients six months after treatment with psilocybin.[30]

An open-label study was carried out in 2016 in the UK to investigate the feasibility, safety and efficacy of psilocybin in treating patients with unipolar treatment-resistant depression with promising results; although the study was small and involved only twelve patients, seven of those patients met formal criteria for remission one week following psilocybin treatment and five of those were still in remission from their depression at three months.[31]

The mechanism behind this is not known as of yet, but researchers have suggested that psilocin's deactivation of the medial prefrontal cortex[32] (mPFC) may be relevant to its antidepressant effects, as the mPFC is known to be elevated in depression and normalized after effective treatment.[32] mPFC hyperactivity has been associated with trait rumination.[33]

Another possible factor to psilocybin's potential against depression may be that depressed patients with high levels of dysfunctional attitudes were found to have low levels of 5-HT(2A) agonism.[34][35]

Toxicity and harm potential

Radar plot showing relative physical harm, social harm, and dependence of benzodiazepines in comparison to other drugs.[36]

Numerous studies have found that psilocybin mushrooms are physiologically well-tolerated and have extremely low toxicity relative to dose. There is no evidence for long-lasting effects on the brain or other organs and there are no documented deaths attributed to the direct effects of psilocybin mushroom toxicity.[37]

However, it is worth noting that while this substance may not be capable of causing direct bodily toxicity or death, its use can still present serious hazards.

For example, it is capable of strongly impairing the user's judgment and attention, which may promote erratic or dangerous behaviors. In extreme cases, the user may experience delusions e.g. that they are currently inside of a dream and therefore physically invincible, prompting them to jump off of a building or run into oncoming traffic.[38]

Additionally, intense negative experiences and psychotic episodes (i.e. "bad trips") can cause lasting psychological trauma if not properly managed or treated afterward. This is particularly a concern in non-supervised settings or when heavy doses are used.

Psilocybin mushroom usage may trigger or exacerbate symptoms (e.g. delusions, mania, psychosis) in those who have or are predisposed to mental disorders, specifically psychotic disorders such as schizophrenia.[37] Those with a personal or family history of mental disorders (including anxiety and depression) should not use this substance without the advice of a qualified medical professional.

Finally, it should be noted that the evidence of psychedelics' effectiveness as a mental health treatment only applies to the controlled procedures used in clinical settings. The available evidence suggests the substance must be combined with professional psychotherapy to produce enduring effects. Without the appropriate safeguards, attempts at self-medicating with psychedelics may actually worsen conditions like anxiety and other mental health issues.[39]

It is highly advised to use harm reduction practices if using this substance. This includes practices such as:

  • Taking the substance under the supervision of a tripsitter for one's first time or while experimenting with a higher dose
  • Keeping a supply of benzodiazepines or antipsychotics like Seroquel to abort the trip in the case of overwhelming anxiety or psychosis

Lethal dosage

The toxicity of psilocybin and psilocin is extremely low. In rats, the median lethal dose (LD50) of psilocybin when administered orally is 280 milligrams per kilogram (mg/kg).

Psilocybin comprises approximately 1% of the weight of Psilocybe cubensis mushrooms and so nearly 1.7 kilograms (3.7 lb) of dried mushrooms or 17 kilograms (37 lb) of fresh mushrooms would be required for a 60 kilogram (130 lb) person to reach the 280 mg/kg LD50 value of rats.

Based on the results of animal studies, the lethal dose of psilocybin has been extrapolated to be 6 grams, 1000 times greater than the effective dose of 6 milligrams.

Dependence and abuse potential

Like other serotonergic psychedelics, psilocybin mushrooms have low abuse and no physical dependence potential.[40]

There are no literature reports of successful attempts to train animals to self-administer psilocybin or psilocybin mushrooms — an animal model predictive of abuse liability — indicating that it does not have the necessary pharmacology to either initiate or maintain dependence.[41]

Likewise, there is no human clinical evidence that psilocybin mushrooms causes addiction. Finally, there is virtually no withdrawal syndrome when chronic use of psilocybin mushrooms is stopped.

Tolerance to the effects of psilocybin builds almost immediately after ingestion. After that, it takes about 3 days for the tolerance to be reduced to half and 7 days to be back at baseline (in the absence of further consumption).

Psilocybin exhibits cross-tolerance with all psychedelics, meaning that after the consumption of psilocybin all psychedelics will have a reduced effect.

Dangerous interactions

Disclaimer: Psychoactive substances that are reasonably safe to use on their own can suddenly become dangerous or even life-threatening when combined with other substances. The following list includes some known dangerous interactions (although it is not guaranteed to include all of them).

Always conduct independent research (e.g. Google, DuckDuckGo, PubMed) to ensure that a combination of two or more substances is safe to consume. Some of the listed interactions have been sourced from TripSit.

  • Amphetamines - Stimulants increase anxiety levels and the risk of thought loops which can lead to negative experiences
  • Cannabis:[42] Cannabis can have an unexpectedly strong and unpredictable synergy with psilocybin mushrooms. While it is commonly used to intensify or prolong the mushrooms' effects, caution is highly advised as mixing these substances can significantly increase the risk of anxiety, paranoia, panic attacks, and psychosis. Anecdotal reports often describe the ingestion of cannabis as the triggering event for a bad trip or psychosis. Users are advised to start off with only a fraction (e.g. 1/4th - 1/3rd) of their typical cannabis dose and space out hits to avoid accidental over-intake.
  • Cocaine - Stimulants increase anxiety levels and the risk of thought loops which can lead to negative experiences
  • Tramadol - Tramadol is well known to lower seizure threshold and psychedelics also cause occasional seizures.
  • Lithium - Lithium is commonly prescribed in the treatment of bipolar disorder; however, studies find it can significantly increase the risk of and seizures when combined to psychedelics. As a result, this combination should be strictly avoided.

Legal status

Internationally, psilocybin (but not psilocybin mushrooms) is a Schedule I drug under the Convention on Psychotropic Substances.

"The cultivation of plants from which psychotropic substances are obtained is not controlled by the Vienna Convention. . . . Neither the crown (fruit, mescal button) of the Peyote cactus nor the roots of the plant Mimosa hostilis nor Psilocybe mushrooms themselves are included in Schedule 1, but only their respective principals, mescaline, DMT, and psilocin."

  • Austria: Psilocybin containing mushrooms are illegal to possess in dried form, to sell and to offer, give or get somebody under the SMG (Suchtmittelgesetz Österreich). It is illegal to grow them with the intention of "producing psychotropic substances" (as psilocin and psilocybin) mentioned in BGBl. III Nr. 148/1997 .[43]
  • Bahamas: Psilocybin mushrooms are legal to possess, grow, and consume.[citation needed]
  • Brazil: Possession, production and sale is illegal as it is listed on Portaria SVS/MS nº 344,[44] but mushrooms fall under religious use laws.[citation needed]
  • British Virgin Isles: The sale of mushrooms is illegal, but possession and consumption is legal.[citation needed]
  • Bulgaria: The sale of mushrooms is illegal, but possession and consumption is legal.[citation needed]
  • Belgium: Possession and sale of mushrooms have been illegal since 1988.[citation needed]
  • Canada: Psilocybin and psilocin are illegal to possess, obtain or produce without a prescription or license as they are Schedule III under the Controlled Drugs and Substances Act; however, dried psilocybin mushrooms are openly sold on dozens of Canadian websites. Spores and growing kits are legal to possess. [45]
  • Czech Republic: The distribution (including sale) of mushrooms is illegal, but consumption is legal. The possession of over 40 hallucinogenic caps is considered a crime if they contain more than 50mg of psilocin or the corresponding amount of psilocybin. The possession of more than 40g of hallucinogenic mycelium is considered a crime. If these limits are not exceeded, the act is considered a minor offense and a fine of up to 15 thousand CZK may be imposed.
  • Cyprus: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Denmark: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Finland: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Germany: Psilocybin is illegal to produce, possess or sale under Schedule I of the Narcotics Act (Anlage I BtMG)[46]. Consumption is not illegal. The mushroom and spores by itself are not illegal and only become illegal when containing Psilocybin or Psilocin.
  • Greece: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Ireland: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Iceland: The sale of Psilocybin mushrooms is illegal, but possession and consumption is legal.
  • India: Psilocybin mushrooms are illegal to possess, grow, sale, and consume. However, it is reported that many police departments in undeveloped areas are unaware of the prohibition.
  • Japan: Psilocybin mushrooms are illegal to possess, grow, sale, and consume.[citation needed]
  • Latvia: Hallucinogenic mushrooms, psilocin and psilocybin are Schedule I controlled substances.[47]
  • Luxembourg: Psilocybin is a prohibited substance[48]
  • Mexico: The possession, growth, sale and consumption of mushrooms is illegal. Rules are relaxed regarding religious use however.[citation needed]
  • The Netherlands: The possession, growth, sale and consumption of mushrooms is illegal. However, due to a legal loophole, psilocybin truffles can be legally possessed, grown, sold and consumed.[citation needed]
  • New Zealand: Psilocybin is a Class A substance.[citation needed]
  • Norway: Possession, growth, sale and consumption of mushrooms is illegal. Spores, even though not containing psilocybin, are also illegal.[citation needed]
  • Sweden: Sveriges riksdag added psilocybin mushrooms to schedule I ("substances, plant materials and fungi which normally do not have medical use") as narcotics in Sweden as of Aug 1, 1999, published by Medical Products Agency.[49]
  • Switzerland: Mushrooms of the species Conocybe, Panaeolus, Psilocybe and Stropharia are controlled under Verzechnis D.[50]
  • Turkey: The possession, growth, sale and consumption of mushrooms is illegal.[citation needed]
  • United Kingdom: According to the 2005 Drugs Act, fresh and prepared psilocybin mushrooms are Class A.[51]
  • United States: Psilocybin and psilocin are Schedule I drugs under the Controlled Substances Act of 1970. This means it is illegal to manufacture, buy, possess, process, or distribute without a license from the Drug Enforcement Administration (DEA).[52]. Several US states and cities have decriminalised Psilocybin mushrooms.
    • Oregon: Oregon Measure 109 legalized the use of Psilocybin mushrooms to licensed service providers administering to individuals 21 years of age or older.

See also

External links

Discussion

Literature

References

  1. Guzmán, G., Allen, J. W., & Gartz, J. (1998). A worldwide geographical distribution of the neurotropic fungi, an analysis and discussion. Ann. Mus. Civ. Rovereto, 14, 189-280.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Tylš, F., Páleníček, T., & Horáček, J. (2014). Psilocybin–summary of knowledge and new perspectives. European Neuropsychopharmacology, 24(3), 342-356. https://doi.org/10.1016/j.euroneuro.2013.12.006
  3. Lüscher, C., & Ungless, M. A. (2006). The Mechanistic Classification of Addictive Drugs, 3(11). https://doi.org/10.1371/journal.pmed.0030437
  4. Strassman, R. J. (1984). Adverse Reactions to Psychedelic Drugs: A Review of the Literature. The Journal of Nervous and Mental Disease, 172(10), 577-595. PMID: 6384428
  5. Samorini G. (1992). "The oldest representations of hallucinogenic mushrooms in the world (Sahara Desert, 9000–7000 B.P.)". Integration. 2 (3): 69–78.
  6. Akers BP, Ruiz JF, Piper A, Ruck CA (2011). "A prehistoric mural in Spain depicting neurotropic Psilocybe mushrooms?". Economic Botany. 65 (2): 121–8. doi:10.1007/s12231-011-9152-5.
  7. Hofmann A. (1980). "The Mexican relatives of LSD". LSD: My Problem Child. New York, New York: McGraw-Hill. pp. 49–71. ISBN 978-0-07-029325-0
  8. Wasson RG. (13 May 1957). "Seeking the magic mushroom". Life. Time Inc.: 101–20. ISSN 0024-3019.
  9. Heim R. (1957). "Notes préliminaires sur les agarics hallucinogènes du Mexique" [Preliminary notes on the hallucination-producing agarics of Mexico]. Revue de Mycologie (in French). 22 (1): 58–79.
  10. Hofmann A, Heim R, Brack A, Kobel H (1958). "Psilocybin, ein psychotroper Wirkstoff aus dem mexikanischen Rauschpilz Psilocybe mexicana Heim" [Psilocybin, a psychotropic drug from the Mexican magic mushroom Psilocybe mexicana Heim]. Experientia (in German). 14 (3): 107–9. doi:10.1007/BF02159243. PMID 13537892.
  11. Hofmann A, Heim R, Brack A, Kobel H, Frey A, Ott H, Petrzilka T, Troxler F (1959). "Psilocybin und Psilocin, zwei psychotrope Wirkstoffe aus mexikanischen Rauschpilzen" [Psilocybin and psilocin, two psychotropic substances in Mexican magic mushrooms]. Helvetica Chimica Acta (in German). 42 (5): 1557–72. doi:10.1002/hlca.19590420518.
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  14. Leary T, Litwin GH, Metzner R (1963). "Reactions to psilocybin administered in a supportive environment". Journal of Nervous and Mental Disease. 137 (6): 561–73. doi:10.1097/00005053-196312000-00007. PMID 14087676.
  15. Leary T, Metzner R, Presnell M, Weil G, Schwitzgebel R, Kinne S (1965). "A new behavior change program using psilocybin". Psychotherapy: Theory, Research & Practice. 2 (2): 61–72. doi:10.1037/h0088612.
  16. Matsushima Y, Eguchi F, Kikukawa T, Matsuda T (2009). "Historical overview of psychoactive mushrooms" (PDF). Inflammation and Regeneration. 29 (1): 47–58. https://doi.org/10.2492/inflammregen.29.47. Archived from the original on April 25, 2012.
  17. Griffiths RR, Grob CS (2010). "Hallucinogens as medicine" (PDF). Scientific American. 303 (6): 77–9. https://doi.org/10.1038/scientificamerican1210-76.
  18. Studerus E, Kometer M, Hasler F, Vollenweider FX (2011). "Acute, subacute and long-term subjective effects of psilocybin in healthy humans: a pooled analysis of experimental studies". Journal of Psychopharmacology. 25 (11): 1434–52. https://doi.org/10.1177/0269881110382466. PMID 20855349.
  19. Keim B. (1 July 2008). "Psilocybin study hints at rebirth of hallucinogen research". Wired.com. Retrieved 2011-08-08.
  20. Gilbert J, Şenyuva H (2009). Bioactive Compounds in Foods. John Wiley & Sons. p. 120. ISBN 978-1-4443-0229-5.
  21. Horita, A., & Weber, L. J. (1961). Dephosphorylation of psilocybin to psilocin by alkaline phosphatase. Proceedings of the Society for Experimental Biology and Medicine, 106(1), 32-34.
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