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  • Updated 09.10.2021
  • Expires For CME 09.10.2024

Hallucinogenic mushroom intoxication and poisoning



Hallucinogenic mushroom poisoning is the most common neurotoxic presentation of mushroom toxicity. There are 2 main toxidromes associated with hallucinogenic mushroom poisoning, which are related to the responsible toxin: the psilocybin toxidrome and the muscimol/ibotenic acid toxidrome. Hallucinogenic mushroom toxins produce their associated toxidromes by selectively affecting neurotransmission. Psilocybin and psilocin have serotonergic properties, whereas muscimol is a potent, selective agonist for the GABAA receptors and binds to the same site on the GABAA receptor complex as GABA itself.

Magic mushrooms continue to be fashionable among drug users, especially young drug users, in part because they are often believed to be relatively harmless compared to other hallucinogenic drugs. However, serious adverse outcomes have been reported, including myocardial infarction; severe rhabdomyolysis, acute renal failure, and posterior encephalopathy; and protracted paranoid psychosis. Ingestion of magic mushrooms may result in horror trips combined with self-destructive and suicidal behavior, especially among people with mental or psychiatric disorders (27; 19). Serious and often permanent organ dysfunction or fatalities may result from accidentally ingesting a more toxic mushroom resembling one that is hallucinogenic (eg, mushrooms of the genus Cortinarius, which are nephrotoxic).

No particular diagnostic procedures are available or needed for most patients with hallucinogenic mushroom toxicity. Care of patients with hallucinogenic mushroom poisoning is primarily supportive and symptomatic. Most patients with hallucinogenic mushroom toxicity can be treated without medications. Seizures are uncommon with hallucinogenic mushroom poisoning, except in young children. The vast majority of poisoned individuals recover without serious permanent morbidity. Uncommon fatalities and serious adverse outcomes do occur, however, and include suicide, protracted psychosis, and myocardial infarction.

Key points

• Management of hallucinogenic mushroom poisoning is primarily supportive and symptomatic.

• Hallucinogenic mushroom toxins produce their associated toxidromes by affecting neurotransmission.

• Hallucinogenic mushroom poisoning is rarely fatal.

• Other serious and often permanent organ dysfunction or fatalities may result from accidentally ingesting a more toxic mushroom resembling one that is hallucinogenic.

Historical note and terminology

Basidiomycota are filamentous fungi composed of hyphae and reproduce sexually. Basidiomycota include inter alia some fungi that might be grown or foraged for food (eg, mushrooms, puffballs, bracket fungi, other polypores, and chanterelles) and fungi that infest plants and might be secondarily ingested (eg, smuts, bunts, rusts). The toxidromes associated with fungi of the phylum Basidiomycota include forms of hallucinogenic mushroom poisoning. With hallucinogenic mushrooms ("magic mushrooms" or "shrooms"), exposure to the fungal toxins is generally intentional, whereas the exposure is generally accidental with other forms of mushroom poisoning.

Hallucinogenic mushroom poisoning. Hallucinogenic mushroom poisoning is the commonest neurotoxic presentation of mushroom toxicity.

Psilocybin-containing mushrooms have been used in indigenous New World cultures in religious, divinatory, or spiritual contexts for millennia. They are represented in the Pre-Columbian sculptures and glyphs seen throughout North, Central, and South America.

Religious statues involving Psilocybe mushrooms

Various "mushroom stones" created from 1000 BCE to 500 CE. Stones measure approximately 1 foot tall. (Public domain. Edited using Photoshop CS6 and enlarged using the artificial intelligence software Topaz Gigapixel AI by Dr Do...

In 1800, Everard Brande first reported hallucinogenic mushroom poisoning in the Western medical literature: the disorder affected a father and 4 of his children, in varying degrees, as a function of age and quantity ingested (dose-response effect) (06). The portion of the report dealing with 1 child is abstracted below:

J.S. gathered early in the morning of the third of October [1799], in the Green Park [in London], what he supposed to be small mushrooms; these he stewed with the common additions in a tinned iron saucepan. The whole did not exceed a tea saucerful, which he and four of his children ate the first thing, about eight o'clock in the morning, as they frequently had done without any bad consequence; they afterwards took their usual breakfast of tea, & c. which was finished about nine, when Edward, one of the children (eight years old), who had eaten a large proportion of the mushrooms, as they thought them, was attacked with fits of immoderate laughter, nor could the threats of his father or mother restrain him. To this succeeded vertigo, and a great degree of stupor, from which he was roused by being called or shaken, but immediately relapsed. The pupils of his eyes were, at times, dilated to nearly the circumference of the cornea, and scarcely contracted at the approach of a strong light; his breathing was quick, his pulse very variable, at times imperceptible, at others too frequent and small to be counted; latterly, very languid; his feet were cold, livid, and contracted; he sometimes pressed his hands on different parts of his abdomen, as if in pain, but when roused and interrogated as to it, he answered indifferently, yes, or no, as he did to every other question, evidently without any relation to what was asked. ... By four o'clock every violent symptom had left him, drowsiness and occasional giddiness only remaining, both of which, with some head-ach, continued during the following day.

These mushrooms were later identified as Psilocybe semilanceata ("liberty cap"). Its popular name is based on its resemblance to a Phrygian cap or liberty cap, which is emblematic of a slave's manumission (release from slavery) in classical antiquity. Such a cap is incorporated into the seal of the United States Senate and is portrayed in many iconic images of the national personification symbols of Liberty for the United States and of Marianne for the French Republic since the French Revolution, with similar representations in many other countries. In the 1960s, this species was found to contain the hallucinogenic compound psilocybin.

Psilocybe semilanceata (“liberty cap”) mushroom

In the 1960s, this species was found to contain the hallucinogenic compound psilocybin. (Public domain. Cropped from original.)

In Alice's Adventures in Wonderland (1865), Alice tried portions of the stalk and cap of a mushroom and subsequently experienced distortions of her body image (08; 10). This phenomenon of self-experienced paroxysmal body image illusions involving distortions of the size, mass, or shape of the body or its position in space, often occurring with depersonalization and derealization, was later incorporated into English psychiatrist John Todds description of Alice in Wonderland syndrome in 1955 (34; 23; 22). Although there is no evidence that Dodgson ever tried hallucinogenic mushrooms, he did take belladonna alkaloidsplant-derived anticholinergic agents that have "deliriant" and hallucinogenic potentialfor his insomnia and migraine (20). Apparently he was also aware of accounts of the hallucinogenic effects of Siberian fly agaric mushrooms (20).

Alice meeting a hookah-smoking caterpillar seated on a mushroom (c1865)

English illustrator Sir John Tenniel’s (1820-1914) illustration of Alice meeting the hookah-smoking caterpillar seated on a mushroom, from Lewis Carroll’s “The Nursery ‘Alice’” (Carroll 1889). Alice’s experiences were used as t...

The seeming references to hallucinogenic mushroom ingestion in Alice's Adventures in Wonderland (1865) were revisited a century later. For example, "White Rabbit" is an Alice in Wonderlandinspired song written by Grace Slick, reportedly after a drug-induced "trip" (ie, during a temporary altered state of consciousness induced by consumption of a hallucinogenic substance, most commonly LSD, mescaline, or psilocybin mushrooms). The song specifically references hallucinatory experiences after ingesting "some kind of mushroom" and refers to the similar experiences of "Alice," the protagonist of Lewis Carroll's fantasy works (08; 09; 10):

When men on the chessboard
Get up and tell you where to go
And you've just had some kind of mushroom
And your mind is moving slow
Go ask Alice, I think she'll know

Lyrics from White Rabbit by Grace Slick of the American rock band Jefferson Airplane for their 1967 album Surrealistic Pillow.

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