psilocin, hallucinogenic principle contained in any of various psilocybin mushrooms, notably the two Mexican species Psilocybe mexicana and P. cubensis (formerly Stropharia cubensis). Hallucinogenic mushrooms used in religious ceremonies by Indigenous peoples of Mexico were considered sacred and were called “god’s flesh” by the Aztecs. In the 1950s the active principles psilocin and a closely related substance called psilocybin were isolated from the Mexican mushrooms. As a result of their subsequent recreational abuse, psilocin and psilocybin and the mushrooms that contain them came under strict regulatory control.
Psilocin and psilocybin are not used in modern medicine, but research suggests that they may have potential applications in the treatment of anxiety and in the improvement of quality of life for terminally ill patients. The substances have also been used in human subjects to better understand the effects of hallucinogens on the brain and to investigate various aspects of psychosis, personality, and consciousness.
Chemically, psilocin is an indole hallucinogen. It acts by altering the action of serotonin (an indole amine neurotransmitter) that occurs in brain tissue.
Psilocin, like psilocybin, produces a hallucinogenic experience similar to those produced by mescaline and LSD (lysergic acid diethylamide). Its duration of action is several hours.