Marsh Chapel Experiment
The Marsh Chapel Experiment (a.k.a. "the Good Friday Experiment") was a 1962 experiment conducted on Good Friday at Boston University's Marsh Chapel. Walter N. Pahnke, a graduate student in theology at Harvard Divinity School, designed the experiment under the supervision of Timothy Leary and the Harvard Psilocybin Project. Pahnke's experiment investigated whether psilocybin (the active principle in psilocybin mushrooms) would act as a reliable entheogen in religiously predisposed subjects.
Prior to the Good Friday service, graduate degree divinity student volunteers from the Boston area were randomly divided into two groups. In a double-blind experiment, half of the students received psilocybin, while a control group received a large dose of niacin. Niacin produces clear physiological changes and thus was used as a psychoactive placebo. In at least some cases, those who received the niacin initially believed they had received the psychoactive drug.:5
However, the feeling of face flushing (turning red, feeling hot and tingly) produced by niacin subsided over the first hour or so. Meanwhile, the effects of the psilocybin intensified over the first few hours. Almost all of the members of the experimental group reported experiencing profound religious experiences, providing empirical support for the notion that psychedelic drugs can facilitate religious experiences. One of the participants in the experiment was religious scholar Huston Smith, who would become an author of several textbooks on comparative religion. He later described his experience as "the most powerful cosmic homecoming I have ever experienced."
Doblin's follow-up 
In a 25-year follow-up to the experiment, all of the subjects given psilocybin described their experience as having elements of "a genuine mystical nature and characterized it as one of the high points of their spiritual life".:13 Psychedelic researcher Rick Doblin considered Pahnke's original study partially flawed due to incorrect implementation of the double-blind procedure, and several imprecise questions in the mystical experience questionnaire. Nevertheless, Doblin said that Pahnke's study cast "a considerable doubt on the assertion that mystical experiences catalyzed by drugs are in any way inferior to non-drug mystical experiences in both their immediate content and long-term effects".:24 A similar sentiment was expressed by psychiatrist William A. Richards, who in 2007 stated "[psychedelic] mushroom use may constitute one technology for evoking revelatory experiences that are similar, if not identical, to those that occur through so-called spontaneous alterations of brain chemistry."
Griffiths' study 
In 2006, a more rigorously controlled version of this experiment was conducted at Johns Hopkins University by Roland R. Griffiths, yielding similar results. In a 14-month follow-up to this study, over half of the participants rated the experience among the top five most meaningful spiritual experiences in their lives, and considered the experience to have increased their personal well-being and life satisfaction.
See also 
- Pahnke WN. (1966). "Drugs and mysticism". International Journal of Parapsychology 8 (2): 295–315.
- Pahnke, Walter N., Drugs and Mysticism: An Analysis of the Relationship between Psychedelic Drugs and the Mystical Consciousness. A thesis presented to the Committee on Higher Degrees in History and Philosophy of Religion, Harvard University, June 1963. Cited in Masters, R.E.L., & Houston, Jean., The Varieties of Psychedelic Experience (Turnstone Books, 1973).
- Doblin R. (1991). "Pahnke's "Good Friday Experiment": a long-term follow-up and methodological critique" (PDF). Journal of Transpersonal Psychology 23 (1): 1–25.
- Smith H. (2000). Cleansing the Doors of Perception: The Religious Significance of Entheogenic Plants and Chemicals. New York, New York: Jeremy P. Tarcher/Putnam. p. 101. ISBN 978-1-58542-034-6.
- Richards WA. (2008). "The phenomenology and potential religious import of states of consciousness facilitated by psilocybin". Archive for the Psychology of Religion 30 (1): 189–199. doi:10.1163/157361208X317196.
- Griffiths RR, Richards WA, McCann U, Jesse R. (2006). "Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance" (PDF). Psychopharmacology 187 (3): 268–83. doi:10.1007/s00213-006-0457-5. PMID 16826400.
- Griffiths R, Richards W, Johnson M, McCann U, Jesse R. (2008). "Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later" (PDF). Journal of Psychopharmacology 22 (6): 621–32. doi:10.1177/0269881108094300. PMC 3050654. PMID 18593735.
- Roberts, T. B. (editor) (2001). Psychoactive Sacramentals: Essays on Entheogens and Religion. San Francosco: Council on Spiritual Practices.
- Roberts, T. B., and Hruby, P. J. (1995-2002). Religion and Psychoactive Sacraments An Entheogen Chrestomathy. Online archive. 
- Roberts, T. B. "Chemical Input—Religious Output: Entheogens." Chapter 10 in Where God and Science Meet: Vol. 3: The Psychology of Religious Experience Robert McNamara (editor)(2006). Westport, CT: Praeger/Greenwood.
- Erowid's Pahnke Vault Contains copious information and documentation, including Pahnke's doctoral dissertation "Drugs and Mysticism"
- A brief video describing the immediate and long term effects of the Marsh Chapel Experiment on Reverend Randall Laakko
- Media reports of 2006 Johns Hopkins Research including ABC News video, The Wall Street Journal, The Washington Post, and The New York Times
- A newspaper article describing the experiment in more detail, with a focus on the experiment's immediate and long term effects on Reverend Mike Young
- "Entheogens—Sacramentals or Sacrilege?" syllabus for a university course
- Johns Hopkins Medicine press release (2006)