a long-term follow-up and methodological critique; Doblin 1991

On Good Friday 59 years ago Walter Pahnke, a Protestant minister, MD, and Harvard Divinity School graduate student, gave twenty divinity students capsules to consume before attending a Good Friday service. Half of those students were plunged into their first psilocybin trip, while the other half remained sober on a placebo.

Between 24 and 27 years later, Rick Doblin, Founder and Executive Director of the Multidisciplinary Association for Psychedelic Studies (MAPS) found the original participants and conducted a follow-up study to understand the long-term effects of these student’s 1962 Good Friday experience.

Pahnke’s “Good Friday Experiment”: a long-term follow-up and methodological critique

William Pahnke partnered with Timothy Leary on this study to understand if psychedelics could induce the kind of mystical experiences described by Christian visionaries and prophets.
Most studies at the time were not well controlled and imbued with various biases of psychedelic-doting researchers. This study would be randomized controlled, matched group, and double blind (i.e. both researchers and participants do not know who has drug and who has placebo).

Twenty divinity students were paired in two according to score similarity on a series of physiological and physical tests.
On the morning of the experiment, a coin was flipped to randomly decide which student would receive 30 mg psilocybin, and which would receive placebo.
The student pairs were matched into 5 groups of 4, with two research assistants per group for support.
- Despite Pahnke’s objections, Leary randomly assigned each group leader either 15 mg of psilocybin or placebo, in order to aid in the leader’s ability to facilitate the participant’s experiences.
After ingesting their assigned capsule, the students read from the Bible, were blessed by the Harvard dean of theology, and then attended a three hour Good Friday service.
Following the experiment, the students were asked to describe their experience, and to fill out a questionnaire 1-2 days and 6 months after the experience.
The questionnaires were developed to assess nine characteristics of mystical experiences including; a sense of unity; transcendence of time and space; deeply felt positive mood; ineffability; paradoxicality; transiency; and persisting positive changes in mood and behavior. The raters also assessed the participants descriptions based on these characteristics.

Pahnke reported that “eight out of ten experimental subjects experienced at least seven out of the nine [mystical] categories. None of the control group, when compared to his matched partner, had a score which was higher.”
In every general category and specific question, the psilocybin-receivers scored higher than his placebo-matched partner, all significant at P<0.05.

The experiment’s raw data and uncoded identities of the participants were lost, however, Rick Doblin identified and located 19 out of the 20 original participants. He was able to administer a follow-up questionnaire and interview to 16 of these participants, 9 from the control group and 7 from the experimental group.
Over twenty years later, the participants who received psilocybin unanimously described their 1962 Good Friday experience as having had genuinely mystical elements and as being one of the high points in their spiritual lives.
Some reported their experience was directly related to Christ, while others had a more universal spiritual nature.
Common themes described by these participants center around appreciation of life and of nature, deepened sense of joy, deepened commitment to the Christian ministry or to whatever other vocations the subjects chose, enhanced appreciation of unusual experiences and emotions, increased tolerance of other religious systems, deepened equanimity in the face of difficult life crises, and greater solidarity and identification with foreign peoples, minorities, women and nature.
Most of the control subjects could remember few details of the 1962 Good Friday Service.

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a long-term follow-up and methodological critique; Doblin 1991

Pahnke’s “Good Friday Experiment”: a long-term follow-up and methodological critique