Psilocybin, the active ingredient of “magic mushrooms,” expands the mind. After a thousand years of use, that’s now scientifically official.

The chemical promoted a mystical experience in two-thirds of people who took it for the first time, according to a new study. One-third rated a session with psilocybin as the “single most spiritually significant” experience of their lives. Another third put it in the top five.

The study, published Tuesday in the journal Psychopharmacology, is the first randomized, controlled trial of a substance used for centuries by natives of Mexico and Central America to produce mystical insights. It is also nearly the first research on a psychedelic drug in human subjects in this country since the 1960s. It confirms what both shamans and hippies long said – taking psilocybin is a scary, reality-bending and occasionally life-changing substance.

The researchers hope the experiment opens a door to the study of a class of compounds that alter human perception and erode the boundaries of self – at least in some users.

They hope it will provide new insight to how the brain works and what neurochemical events underlie moments of mystical rapture.

If the generally positive effects of the drug are confirmed by other studies, the research will likely raise the question whether people should be allowed access to psilocybin for self-improvement or recreation.

Rigorous study of these substances has been shunned since the 1960s, although it is not legally prohibited.