A Study of Psilocybin for PTSD

This study uses a randomized controlled design to compare the safety and efficacy of 2 doses of psilocybin for PTSD. In addition, it will investigate the effects of trauma-focused psychotherapy (which includes standard psychological support) versus standard psychological support alone. Twenty participants will be recruited. Following the first psilocybin session, participants will be randomized to either the trauma-focused psychotherapy (which includes standard psychological support) treatment condition or the standard psychological support treatment condition (the latter being typical for the experimental administration of psilocybin therapy). Both groups will receive identical treatment prior to receiving the first dose of psilocybin, with one group receiving procedures related to trauma-focused psychotherapy (combined with standard psychological support) beginning after receipt of psilocybin. The study will include clinician and participant ratings of PTSD and mood symptoms pre- and post-drug session and monitor and participant ratings of subjective drug effects during and after each drug session. The intervention for both groups will consist of about 8 hours of preparatory meetings (over approximately 2 weeks), followed by 2 psilocybin sessions separated by approximately 2 weeks. The initial psilocybin dose will be 25 mg. The dose for the second session may be increased conditional on the strength of subjective effects, as measured by the Mystical Experiences Questionnaire (MEQ30), taken at the end of participants' first psilocybin session. This allows a dose to increase if, for example, concomitant serotonin reuptake inhibitors reduce subjective effects. Participants with a score ≥60% of the maximum on the MEQ30 will remain at a dose of 25 mg of psilocybin for the second session. Participants with an MEQ30 score below 60% will receive a dose of 40 mg for the second session. Elevation of dose will also be based on the clinical judgment of the principal investigator, study physician, and study staff that a higher dose can be safely administered. In addition, participants who prefer to not elevate the dose will remain at 25 mg for the second session. To support the participant's therapeutic integration of psilocybin experiences, following each psilocybin session, participants will meet with the session facilitator(s) at multiple scheduled time points. Additional contact hours will be scheduled if it is judged that the participant would benefit from additional meetings to discuss experiences from the session(s) or to prepare for the next session. This study is supported in part by philanthropic contributions from private individuals. These donors are not involved in the design, conduct, or analysis of the research.