Harvard Mental Health Letter

Reviving the study of hallucinogens

The word "psychedelic," invented by the psychiatrist Humphry Osmond in the 1950s, comes from Greek roots that mean "mind-revealing." An experiment conducted in 2005 at Johns Hopkins University suggests that this term accurately describes an experience regularly induced by the hallucinogenic drug psilocybin. The findings, reported in the journal Psychopharmacology, are accompanied by four expert commentaries and an editorial.

Psilocybin is the active ingredient of a mushroom (Psilocybe mexicana or Psilocybe cubensis) long used in magical and healing rituals in Mexico and Central America. The Aztecs called it "flesh of the gods." In the Johns Hopkins experiment, it produced mystical experiences with high personal significance and favorable psychological changes lasting at least two months.

After hours of preparatory discussion, each of 30 volunteers took a high dose of either psilocybin or the stimulant methylphenidate (Ritalin), which has similar effects on heart rate and blood pressure. Two months later, each volunteer took the other drug. Another six volunteers received methylphenidate twice and psilocybin in a third session.

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