INTRODUCTION	Section 2 of 9
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Background: Hallucinogenic fungi have been used in divinatory or religious contexts for at least 3000 years. However, not until the 1950s were the involved species of fungi identified and the chemical nature of active substances determined.

In general, 2 groups of mushrooms with significant psychoactive effects exist.

• Mushrooms containing ibotenic acid and muscimol (isoxazoles), including Amanita gemmata, Amanita muscaria (fly agaric), and Amanita pantherina (the panther), comprise the first group. These are not to be confused with deadly Amanita phalloides, Amanita verna, and Amanita virosa. For centuries, A muscaria has been consumed in central Asia as a hallucinogen. Some Siberian tribes report that 3 fresh A muscaria mushrooms can be lethal, while others claim that eating as many as 21 of these mushrooms is safe.

• Psilocybin-containing mushrooms, including Psilocybe caerulipes, Psilocybe cubensis, Gymnopilus spectabilis, Panaeolus species (eg, Panaeolus foenisecii), and Psathyrella foenisecii, comprise the second group of mushrooms with psychoactive effects.

Mushrooms containing ibotenic acid and muscimol and those containing psilocybin are New World fungal hallucinogens. Reports of toxicity associated with this group of mushrooms have increased because of their growing popularity as hallucinogens.

Pathophysiology: Ibotenic acid is an agonist at central glutamic acid receptors; its decarboxylated derivative is an agonist at gamma-amino butyric acid receptors. Central effects of these hallucinogenic mushrooms are thought to be caused by these actions. Although muscarinic acid originally was isolated from A muscaria, the clinical syndrome does not suggest marked significance; in fact, anticholinergic findings may be observed.

The psilocybin group contains the indoles psilocybin and psilocin. Psilocin and its phosphate ester, psilocybin, are similar in structure to lysergic acid diethylamide (LSD). They are structural analogues of serotonin (5-hydroxytryptamine); thus, hallucinogenic effects probably are mediated through effects on serotonergic receptors.

Frequency:

• In the US: Estimating frequency of hallucinogenic mushroom use is difficult. Psilocybin-containing mushrooms are popular recreational drugs of abuse.

Mortality/Morbidity: Mortality from hallucinogenic mushrooms is very rare.

Age: While little data exist on the age of users of hallucinogenic mushrooms, college students are known to abuse psilocybin mushrooms.

	CLINICAL	Section 3 of 9
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History: Hallucinogenic mushrooms usually are ingested for their psychoactive properties.

• Mushrooms containing ibotenic acid and muscimol

• Symptoms begin 30 minutes to 1 hour postingestion; however, symptom onset rarely may be delayed as long as 3 hours.

• Hallucinations may be accompanied by dysarthria, dystaxia, and muscle cramps and may persist for as long as 8 hours. However, a recent case report describes an otherwise healthy 48-year-old man who accidentally ingested A muscaria mushrooms. He experienced a 5-day paranoid psychosis accompanied by visual and auditory hallucinations. By the sixth day, he had returned to baseline, with no long-term adverse effects reported (Brvar, 2006).

• Central nervous system (CNS) effects range from agitation to coma.

• Heavy intoxication may cause vomiting, diarrhea, and seizures.

• Fatal A pantherina poisonings have been reported in the Pacific Northwest.

• Psilocybin-containing mushrooms

• Alterations in perception begin within 30 minutes and subside after 6 hours.

• Widely varying CNS manifestations, including euphoria and visual and religious hallucinations, have been reported. Visual hallucinations may include perceived motion of stationary objects or surfaces.

• Patients presenting in the ED may experience more unpleasant effects such as fear, agitation, confusion, delirium, psychosis, and schizophrenialike syndromes.

• Symptoms may include nausea and sympathomimetic activity such as mydriasis and tachycardia.

• Frequent use may cause transient elevation of hepatic enzymes.

• Symptoms in children include hyperpyrexia and seizures.

Physical: Predominant findings in these intoxications are neurologic.

Fever, tachycardia, and hypotension may occur because of agitation.

• Neurologic findings

• Ataxia

• Incoordination

• Confusion

• Delirium

• Psychosis