Psilocybin and Mystical Experiences
"Overall, the present study shows that psilocybin can dose-dependently occasion mystical-type experiences having persisting positive effects on attitudes, mood, and behavior. The observations that episodes of extreme fear, feeling trapped, or delusions occur at the highest dose in almost 40% of volunteers, that anxiety and fear have an unpredictable time course across the session, and that an ascending sequence of dose exposure may be associated with long-lasting positive changes have implications for the design of therapeutic trials with psilocybin. Considering the rarity of spontaneous mystical experiences in the general population, the finding that more than 70% of volunteers in the current study had 'complete' mystical experiences suggests that most people have the capacity for such experiences under appropriate conditions and, therefore, such experiences are biologically normal."
Griffiths, Roland R.; Johnson, Matthew W.; Richards, William A.; Richards, Brian D.; McCann, Una; and Jesse, Robert, "Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects," Psychopharmacology (Heidelberg, Germany: May 2011), p. 16.