Encyclopedia of Psychology and Religion

Living Edition
| Editors: David A. Leeming

The Good Friday Experiment (Aka Marsh Chapel Experiment)

  • Katie Givens KimeEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27771-9_200209-1

A landmark experiment in the history of the psychology of religion was the 1962 “Marsh Chapel Experiment,” also known as the “Good Friday Experiment,” and popularized in the press at the time as “The Miracle in Marsh Chapel.”

Twenty Christian seminarians participated in a double-blind study of psilocybin, designed by Walter N. Pahnke, a psychiatrist and ordained minister completing his doctoral work in the History and Philosophy of Religion at Harvard. While Howard Thurman preached on the Last Words of Christ in Marsh Chapel at Boston University, the clinical study took place in a basement sanctuary, directly below the pulpit, while the audio feed of the Good Friday worship service was broadcast into the space.

Pahnke wrote that the experiment investigated “in a systematic and scientific way the similarities and differences between experiences described by mystics and those facilitated by psychedelic drugs.” The results of the study, intentionally conducted in “a religious context” with religiously inclined individuals, led Pahnke and others to find “that psilocybin (and LSD and mescaline, by analogy) are important tools for the study of the mystical state of consciousness” (Pahnke 1966).

Walter Houston Clark, a professor of the psychology of religion, helped recruit the 20 white male volunteers from the Andover Newton Theological Seminary, where he taught. Eight of the ten who received psilocybin reported dramatic mystical experiences, and some reportedly wandered about the chapel crying aloud, “God is everywhere” and “Oh, the glory!” By contrast, only one of the ten control group (who were given Nicotinic Acid as an active placebo to maximize suggestion) participants experienced elevated mystical feelings. In addition, Pahnke recruited ten additional volunteers to serve as “guides.” Timothy Leary, the Harvard faculty sponsor for Pahnke’s experiment and co-leader of the Harvard Psilocybin Project, suggested that the guides also should be included in receiving psilocybin or placebos (Doblin 1991).

For scholars of religion, perhaps the most notable of these volunteer guides was Huston Smith, the foremost twentieth-century scholar of comparative world religions, who referred to his psilocybin experience that day as his “cosmic rebirth.” For the remainder of his life, Smith wrote and spoke about the noetic quality of his mystical experience triggered by psilocybin. Emerging from the experience, he felt transformed and utterly convicted “that life really is a miracle, every moment of it, and that the only appropriate way to respond to the gift we have been given is to be mindful of that gift at every moment, and to be caring toward everyone we meet” (Horgan 2017). Smith reported a lifelong belief in and experiences of God, “[b]ut until the Good Friday Experiment, I had had no direct personal encounter with God of the sort that bhakti yogis, Pentecostals, and born-again Christians describe. The Good Friday Experiment changed that, presumably because the service focused on God as incarnate in Christ” (Smith 2000, pp. 100–101).

Pahnke’s methodology included the creation of a phenomenological typology, largely based on W. T. Stace’s 1961 classic, Mysticism and Philosophy. Stace defined seven universal characteristics of mystical experience and set aside delineations of religion or religiousness. In Pahnke’s typology, he constructed nine categories: unity (internal and external), transcendence of time and space, deeply felt positive mood, sacredness, objectivity and reality, paradoxicality, alleged ineffability, transiency, and persisting positive changes in attitude and behavior (Pahnke 1966).

Smith described how participant accounts were gathered: “The day after the experiment we would write reports of our experiences, and Pahnke would have them scored by independent raters on a scale of from zero to three for the degree to which each subject’s experience included the seven traits of mystical experience [from Stace]. There was one borderline case, but apart from that, the experiences of those who received psilocybin were dramatically more mystical than those in the control group” (Smith 2000, p. 100). Pahnke included a 6-month follow-up questionnaire and interview as part of the experiment, which aimed to determine perceptions, positive or negative, of attitudinal or behavioral changes on the part of each participant.

Twenty-five years after the 1962 experiment, Rick Doblin conducted a “Long-Term Follow-Up and Methodological Critique,” published in The Journal of Transpersonal Psychology in 1991. Of the ten original volunteers who received psilocybin, seven (most of whom became ordained clergy) were eager to participate. Of the remaining three, one had since died, and one refused to be interviewed because of his misunderstanding of his pledge of confidentiality to Pahnke (who died in a scuba-diving accident in 1971). The story of the final participant, according Huston Smith and Rick Doblin, reveals some grave omissions in Pahnke’s reporting of participant experience and methodology. The final participant, who Smith anonymously references as “John,” had an extraordinarily negative experience, escaping the basement space and running onto Commonwealth Avenue. Smith, who first chased after John, reports that the participant was convinced that “God…had chosen him to announce to the world the dawning of the Messianic Age, a millennium of universal peace” and that he needed to reach the university dean so he might hold a press conference. Once John was sufficiently overpowered by Pahnke and his assistants and returned to the chapel, Pahnke injected Thorazine as a tranquilizer and antidote to John’s psychotic state. Though he participated in the 6-month follow-up (and reported only “slightly harmful” negative persisting effects), John refused to participate in Doblin’s 25th-year retrospective study and made clear that he had very negative feelings about the experience.

In addition to omitting his administration of Thorazine to a participant, it has been speculated that Pahnke may have minimized the reports of anxiety and other negative experiences from participant testimonials and questionnaire results. Nevertheless, Pahnke’s study made a significant contribution in demonstrating the potential of entheogens in triggering mystical experiences. It is noteworthy that despite reported difficult moments for the participants, all the subjects who participated in Doblin’s follow-up study were overwhelmingly positive and “reported a substantial amount of persisting positive effects and no significant long-term negative effects” 25 years later.

The Good Friday experiment continues to serve as a paradigmatic model of psychedelic research, though it was certainly not the only one. In the 1950s, following Albert Hofmann’s discovery of LSD, many European and American scholars and psychiatrists eagerly explored the clinical and existential potential for what might be a new “royal road to the unconscious.” In this period, more than a thousand clinical papers were produced, discussing more than 40,000 patients (Grinspoon and Bakalar 1979, p. 192) who were treated with LSD, psilocybin, and other psychedelics (also known as entheogens) for addiction, depression, autism, and schizophrenia.

After several decades of halted research, due to federal bans on psychedelic substances (even for research purposes), several aspects of the Good Friday experiment were successfully replicated (with more robust controls), and yielded similar results. Roland Griffiths, a leading researcher of drug-addiction and senior scholar in psychiatry and neuroscience, published in Psychopharmacology in 2006 the results of a landmark study, “Psilocybin can Occasion Mystical-Type Experiences Having Substantial and Sustained Personal Meaning and Spiritual Significance.” In Griffiths’ and related studies to follow, empirically-structured double-blind experiments were designed to prompt religious and mystical experiences for terminally ill patients experiencing “existential distress.” Results showed that 70% of research subjects named their single psilocybin-assisted therapy session as one of the five most meaningful experiences of their lives, and reported dramatic relief of previously reported distress.

The high drama of the Good Friday Experiment may be contrasted with scenes from psilocybin therapy sessions today at Johns Hopkins School of Medicine, New York University School of Medicine, and other institutions, which include a well-appointed room, decorated with books and art representing various myths and religious traditions, a comfortable couch-bed for participants, with headphones and an eye mask. On a table nearby is a ceramic chalice in which patients are given a single pill, either a placebo or dose of psilocybin. Two clinicians (usually male and female) often attend the participant for the entire 7-h session. It is a carefully curated, institutionally sanctioned experience, but from the reports of participants, the spiritual experiences are no less notable in their consistently transformative nature.

At the time of this publication, the Johns Hopkins School of Medicine was recruiting participants for a study entitled, “The Effects of Psilocybin-Facilitated Experience on the Psychology and Effectiveness of Religious Professionals,” in collaboration with New York University. Such trials are premised on the hypothesis “that religious professionals, given their interests, training, and life experience, will be able to make nuanced discriminations of their psilocybin experiences, thus contributing to the scientific understanding of mystical-type experience” (Ross 2013). For scholars of the psychology of religion, this is a fascinating and important indication of innovative future research trajectories and methodologies.

See Also


  1. Doblin, R. (1991). Pahnke’s “Good Friday experiment”: A long-term follow-up and methodological critique. The Journal of Transpersonal Psychology, 23(1), 1; Palo Alto, Calif.Google Scholar
  2. Griffiths, R., Johnson, M., Richards, W., Richards, B., McCann, U., & Jesse, R. (2011). Psilocybin occasioned mystical-type experiences: Immediate and persisting dose-related effects. Psychopharmacology, 218(4), 649–665.  https://doi.org/10.1007/s00213-011-2358-5.CrossRefPubMedPubMedCentralGoogle Scholar
  3. Grinspoon, L., & Bakalar, J. B. (1979). Psychedelic drugs reconsidered. New York: Basic Books.Google Scholar
  4. Horgan, J. (2017). R.I.P. Huston Smith, religious scholar who defended psychedelics’ spiritual potential. Scientific American Blog Network. https://blogs.scientificamerican.com/cross-check/r-i-p-huston-smith-religious-scholar-who-defended-psychedelics-spiritual-potential/, accessed 11 Aug 2018.
  5. Pahnke, W. N. (1966). Drugs and mysticism. International Journal of Parapsychology, 8(2), 295–314.Google Scholar
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  7. Roberts, T. B. (2014). From the 500-year blizzard of words to personal sacred experiences – The new religious era. In J. H. Ellens (Ed.), Seeking the sacred with psychoactive substances: Chemical paths to spirituality and to god (Vol. 1, pp. 1–22). Santa Barbara: Praeger, an imprint of ABC-CLIO, LLC.Google Scholar
  8. Ross, S. (2013, April). Psilocybin, addiction, and end of life. Presented at the psychedelic science conference, Oakland. Retrieved from https://www.youtube.com/watch?v=JMwkX6j2IjA
  9. Smith, H. (2000). Cleansing the doors of perception: The religious significance of entheogenic plants and chemicals. New York: Jeremy PTarcher/Putnam.Google Scholar
  10. Stace, W. T. (1961). Mysticism and philosophy. London: Macmillan.Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute of Practical TheologyUniversity of BernBernSwitzerland