Johns Hopkins Psilocybin Follow-Up Study

The Johns Hopkins Psilocybin Follow-Up Study examined whether the changes people described after psilocybin sessions endured beyond the immediate experience. Survey data from 52 healthy volunteers, supplemented by interviews with friends and family members the volunteers had nominated, showed lasting improvements in well-being and long-term increases in openness to experience among those who had complete mystical experiences. The study made personal transformation more than an anecdotal claim, while also placing its findings within the limits of the measures used to assess it.

Design and Measures

Psychologist Katherine MacLean analyzed the surveys and follow-up interviews from the first groups of healthy volunteers studied at Johns Hopkins. The researchers classified a volunteer’s experience as a complete mystical experience according to scores on the Pahnke-Richards Mystical Experience Questionnaire. The follow-up therefore connected reported session experiences with later assessments of participants’ lives and personalities, and sought perspectives from people close to them as well as from the volunteers themselves.

The study identified two distinct lasting changes for volunteers whose sessions met that questionnaire threshold: improved well-being and increased openness to experience. Its reported findings were specific to this group; they did not establish that every participant changed in the same way or that the results applied to people whose sessions did not qualify as complete mystical experiences.

Openness and Its Significance

Openness to experience is one of the five personality traits used by psychologists, alongside conscientiousness, extroversion, agreeableness, and neuroticism. It encompasses aesthetic appreciation and sensitivity, fantasy and imagination, and tolerance of other people’s viewpoints and values. The book also notes that openness predicts creativity in the arts and sciences and may accompany a willingness to consider ideas that conflict with prevailing scientific views.

The finding’s significance lay partly in the duration and kind of change reported: pronounced, lasting shifts in adult personality are rare. The study thus connected a defined category of session experience with an enduring change in a broad personality trait, rather than treating the session as an intense but necessarily transient episode.

Changes in Participants’ Lives

Accounts from volunteers give individual form to the wider pattern of reported change, though they should not be confused with the study’s measured results. Brian Turner, a physicist who had meditated before his psilocybin experience, left his job with a military contractor and moved to Colorado to study Zen. He later became an ordained Zen monk while continuing to work as a physicist for a helium-neon laser company. He described the experience as giving him a preview of modes of consciousness he then wanted to pursue through the sustained practice of Zen.

Turner did not see his scientific work and spiritual practice as contradictory. He said that what happened at Johns Hopkins had influenced his physics, while also leading him to believe that science could not reach every domain of experience. His account shows one possible life consequence of the experience: not abandonment of scientific work, but a changed sense of what it could and could not address.

Effects Beyond the Volunteers

The changes described around the sessions were not confined to participants. MacLean, who guided dozens of sessions at Johns Hopkins, said that she had begun on the atheist side, but that witnessing people’s experiences in her work repeatedly challenged that belief and made her world seem increasingly mysterious. Her account was a personal reflection, not a result of the volunteer follow-up; it nevertheless points to a further consequence of the research setting, in which guides themselves could be affected by witnessing participants’ journeys.

Taken together, the follow-up findings and these individual accounts distinguish lasting change from the intensity of a single session. The survey supplied evidence of durable shifts in well-being and openness among volunteers reporting complete mystical experiences; the surrounding narratives show how such shifts could take different forms in practice, from renewed spiritual discipline to a changed outlook among those guiding the sessions.