This Phase II, randomised, open-label, parallel trial (n=150) will evaluate the safety, tolerability, acceptability and preliminary efficacy of a single 25 mg dose of psilocybin administered with two different psychotherapy approaches in Georgia military service members, reservists, National Guard members or active-duty personnel seeking treatment for PTSD. The primary aims are to pilot tolerability and safety and to compare changes in PTSD symptoms between psilocybin plus supportive therapy and psilocybin plus massed prolonged exposure (PE) therapy. Participants will be randomised to receive a single 25 mg psilocybin dosing session paired either with supportive (non-directive) therapy—comprising preparatory work and two integrative support sessions one week apart with online surveys between sessions—or with massed PE consisting of 10 manualised PE sessions delivered over 10 days with imaginal and in vivo exposure homework and interim online surveys. Safety and tolerability will be assessed using the Swiss Psychedelic Side Effects Inventory (SPSI), Psychedelic-assisted Therapy After Effects (PATAE) and the Accessibility Questionnaire (AQ); other outcomes include Subjective Units of Distress (SUDS) during imaginal exposure, fear extinction and recall assessed by fear potentiated startle, and symptom measures (CAPS-5-R change baseline to 1 month, PCL-5 at baseline, 1, 6 and 12 months, and PHQ-9 at baseline, 1, 6 and 12 months). The study is planned to run from March 2026 to March 2027.
This pilot study will examine the safety, tolerability, acceptability, and efficacy of combination psilocybin + psychotherapy to decrease PTSD symptoms. Participants will be randomized into two different treatment groups, allowing the investigators to directly compare PE augmented with psilocybin and psilocybin-assisted psychotherapy.
All participants will receive a single 25 mg dose of psilocybin during the experimental session, which occurs during to their respective therapy model. Then, participants will receive 2 support (integrative) therapy sessions that will be 1 week apart. In between these sessions, subjects will complete a series of online surveys to track treatment progress.
All participants will receive a single 25 mg dose of psilocybin during the experimental session, followed by 10 prolonged exposure (PE) therapy sessions for 10 days. In between these sessions, participants will complete a series of online surveys to track treatment progress.