Investigating the safety and tolerability of single-dose psilocybin for post-traumatic stress disorder: A nonrandomized open-label clinical trial
In a Phase 2, non-randomised open-label trial of 22 adults with PTSD, a single 25 mg dose of psilocybin administered with psychological support was generally well tolerated with no serious adverse events and mostly transient side-effects, and was associated with large, clinically meaningful reductions in PTSD symptoms and improvements in functioning and quality of life sustained to 12 weeks. These results indicate single-dose psilocybin may be safe and potentially efficacious for PTSD, warranting further controlled investigation.
Authors
- Guy Goodwin
- Manish Agrawal
- Nadav Liam Modlin
Published
Abstract
Background
Post-traumatic stress disorder (PTSD) is a debilitating condition for which there are few efficacious treatments. Psilocybin is being studied for use in treatment-resistant depression but has not yet been investigated in PTSD.
Aims
The trial’s primary outcome was to investigate the safety and tolerability of single-dose psilocybin in participants with PTSD.
Methods
This was a Phase 2, nonrandomized, open-label, multicenter trial. Secondary outcomes were changes in PTSD symptoms (Clinician-Administered PTSD Scale for DSM-5 (CAPS-5); PTSD Checklist for DSM-5 (PCL-5)), functional impairment (Sheehan Disability Scale; SDS) and quality of life (EQ-5D-5L index score).
Results
Amongst the 22 participants enrolled (63.6% female; mean (SD) age, 39.0 (7.91) years), there was a total of 117 treatment-emergent adverse events (TEAEs); 70 (59.8%) were reported on administration day, of which 64/70 (91.4%) resolved by the end of the next day. TEAEs commonly included headache ( n = 11; 50.0%), nausea ( n = 8; 36.4%), crying ( n = 6; 27.3%) and fatigue ( n = 6; 27.3%). There were no serious TEAEs or TEAEs leading to study withdrawal. Pre-post comparisons indicated a clinically meaningful change from Baseline in mean CAPS-5 total score at Week 4 (−29.9 (14.06)) and Week 12 (−29.5 (15.43)), which was associated with the intensity of psychedelic experience on Day 1. PCL-5 scores showed symptom reduction was rapid and sustained until Week 12. SDS total score and EQ-5D-5L index score showed similar improvements.
Conclusions
Psilocybin at a dose of 25 mg, administered with psychological support, may be safe, well-tolerated and associated with symptomatic improvement in adults with PTSD. Further investigation is warranted. Clinical trial registration: ClinicalTrials.gov Identifier: NCT05312151 (https://clinicaltrials.gov/study/NCT05312151)
Research Summary of 'Investigating the safety and tolerability of single-dose psilocybin for post-traumatic stress disorder: A nonrandomized open-label clinical trial'
Introduction
PTSD is a common and disabling psychiatric disorder marked by intrusion, avoidance, negative alterations in cognition and mood, and heightened arousal. Existing first-line treatments—principally trauma-focused psychotherapies and selective serotonin reuptake inhibitors (SSRIs)—have important limitations: psychotherapies are time-intensive, often poorly tolerated, and suffer high dropout, while SSRI efficacy is modest with remission rates below 30% and high levels of polypharmacy and non-adherence in clinical practice. These gaps have driven interest in novel interventions that may be more tolerable and act more rapidly. This study evaluated COMP360, a pharmaceutical-grade synthetic psilocybin formulation, which has shown promise in treatment‑resistant depression but had not previously been studied in clinically confirmed PTSD. Mcgowan and colleagues designed a Phase II trial to assess the safety and tolerability of a single 25 mg dose of COMP360 psilocybin, with secondary aims to characterise changes in clinician‑rated and self‑reported PTSD symptoms, functional impairment and health‑related quality of life over 12 weeks. The trial also explored whether the qualitative features of the acute psychedelic experience related to clinical outcomes.
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Study Details
- Study Typeindividual
- Journal
- Compound
- Topics
- Authors
- APA Citation
McGowan, N. M., Rucker, J. J., Yehuda, R., Agrawal, M., Modlin, N. L., Simmons, H., Tofil-Kaluza, A., Das, S., & Goodwin, G. M. (2025). Investigating the safety and tolerability of single-dose psilocybin for post-traumatic stress disorder: A nonrandomized open-label clinical trial. Journal of Psychopharmacology. https://doi.org/10.1177/02698811251362390
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Rucker, J. J., Marwood, L., Ajantaival, R. L. J. et al. · Journal of Psychopharmacology (2022)
Studerus, E., Gamma, A., Vollenweider, F. X. · PLOS ONE (2010)
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Modlin, N. L., Williamson, V., Goodwin, G. M. et al. · EClinicalMedicine (2025)
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