Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance Roland R. Griffiths, William A. Richards, Una McCann, Robert Jesse Psychopharmacology, 2006 DOI 10.1007/s00213-006-0457-5   Abstract Rationale : Although psilocybin has been used for centuries for religious purposes, little is known scientifically about its acute and persisting effects. Objectives : This double-blind study evaluated the acute and longer-term psychological effects of a high dose of psilocybin relative to a comparison compound administered under comfortable, supportive conditions. Materials and methods : The participants were hallucinogennaïve adults reporting regular participation in religious or spiritual activities. Two or three sessions were conducted at 2-month intervals. Thirty volunteers [...]