Supervised RCT dosing day: rapid near-remission of severe treatment-resistant OCD after single-dose psilocybin

Source note

Anonymised summary of a published prospective case report (Kelmendi et al., 2022, Heliyon) describing an early participant in NCT03356483. The source used a pseudonym; all personal names and relationship identifiers are removed here.

Participant profile (non-identifying)

• Age / sex: 33-year-old male
• Diagnoses: primary treatment-resistant OCD; history of major depressive episode, Tourette syndrome, and panic disorder
• Illness onset: OCD/Tourette diagnoses from approximately age 10
• Prior care: multiple SSRI trials and CBT without adequate OCD relief
• Baseline severity: Y-BOCS 24 (severe range) at evaluation; A-YBOCS 23 on dosing morning

Intervention

• Randomised to psilocybin 0.25 mg/kg (absolute dose 19.4 mg purified psilocybin)
• Eyes-shade / headphone-supported session with unstructured, non-directive psychological support
• No concurrent psychoactive medications during the study window

Outcome (reported scales)

• A-YBOCS: 23 → 2 at 48 hours
• Y-BOCS: 4 at 1 week; 1 at 4 and 8 weeks; 0 at 12 weeks
• Concurrent improvements reported on depression (BDI-II / MADRS), anxiety (STAI), global severity, and disability measures
• Participant described needing ongoing active self-management of a residual “imprint” of OCD rather than a permanent switch-off

Interpretation guardrails

This is a single high-responder narrative inside a broader trial. The source authors explicitly note that such marked change is not typical of every participant. It illustrates potential magnitude of benefit under controlled conditions, not a guarantee.