title: Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects.
abstract: BACKGROUND
  This dose-effect study extends previous observations showing that psilocybin can occasion mystical-type experiences having persisting positive effects on attitudes, mood, and behavior.
  
  
  OBJECTIVE
  This double-blind study evaluated psilocybin (0, 5, 10, 20, 30 mg/70 kg, p.o.) administered under supportive conditions.
  
  
  METHODS
  Participants were 18 adults (17 hallucinogen-naïve). Five 8-h sessions were conducted individually for each participant at 1-month intervals. Participants were randomized to receive the four active doses in either ascending or descending order (nine participants each). Placebo was scheduled quasi-randomly. During sessions, volunteers used eyeshades and were instructed to direct their attention inward. Volunteers completed questionnaires assessing effects immediately after and 1 month after each session, and at 14 months follow-up.
  
  
  RESULTS
  Psilocybin produced acute perceptual and subjective effects including, at 20 and/or 30 mg/70 kg, extreme anxiety/fear (39% of volunteers) and/or mystical-type experience (72% of volunteers). One month after sessions at the two highest doses, volunteers rated the psilocybin experience as having substantial personal and spiritual significance, and attributed to the experience sustained positive changes in attitudes, mood, and behavior, with the ascending dose sequence showing greater positive effects. At 14 months, ratings were undiminished and were consistent with changes rated by community observers. Both the acute and persisting effects of psilocybin were generally a monotonically increasing function of dose, with the lowest dose showing significant effects.
  
  
  CONCLUSIONS
  Under supportive conditions, 20 and 30 mg/70 kg psilocybin occasioned mystical-type experiences having persisting positive effects on attitudes, mood, and behavior. Implications for therapeutic trials are discussed.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224-6823, USA. rgriff@jhmi.edu
authors.forename: Roland R
authors.initials: RR
authors.lastname: Griffiths
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Johnson
authors.forename: William A
authors.initials: WA
authors.lastname: Richards
authors.forename: Brian D
authors.initials: BD
authors.lastname: Richards
authors.forename: Una
authors.initials: U
authors.lastname: McCann
authors.forename: Robert
authors.initials: R
authors.lastname: Jesse
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects*; D001290:Attitude; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006213:Hallucinogens / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011562:Psilocybin / Q000008:administration & dosage / Q000494:pharmacology*; D029181:Spirituality; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D006213:Hallucinogens; D011562:Psilocybin