Psilocybin mushrooms (also known as magic mushrooms, psychedelic mushrooms, and shrooms) are a family of psychoactive mushrooms that contain the psychedelic tryptamine psilocybin. Psilocybin mushrooms occur on all continents and consist of more than 200 species, the most potent of which belong to the genus Psilocybe. Like other psychedelics, psilocybin mushrooms produce their effects by acting on serotonin receptors in the brain.
Imagery found on prehistoric rock art suggests that the use of psilocybin mushrooms predates recorded history. In Mesoamerica, they have been consumed in ritual ceremonies for 3000 years. They were introduced to the West in 1955 by Gordon R. Wasson. In the 1960s, psilocybin was widely used in the experimental research of mental disorders and in psychotherapy. Popularization by counterculture figures like Timothy Leary led to an explosion of recreational use and resulted in its prohibition in 1970. Today, psilocybin mushrooms are one of the most popular psychedelics and the subject of renewed interest by researchers and clinicians.
The intensity and duration of effects produced by psilocybin mushrooms can vary greatly depending on factors such as species and batch. Common doses of the popular strain P. cubensis range from 2 to 3.5 grams and last for 4 to 6 hours. Notable effects include geometric visual hallucinations, time distortion, enhanced introspection, and ego loss. Psilocybin mushrooms are commonly described by users to evoke entheogenic and mystical-type experiences that can facilitate introspection and personal growth.
Unlike most highly prohibited substances, psilocybin mushrooms are considered to be non-addictive and have low toxicity. Nevertheless, adverse psychological reactions such as anxiety, paranoia, delusions and psychosis can always occur, particularly among those predisposed to mental illness. For this reason, it is highly advised to use harm reduction practices if using this substance.