This randomized, double-blind, placebo-controlled, single ascending dose study will evaluate psilocybin in healthy adult subjects. Each subject will complete Screening within 28 days before admission, a 3-day/2-night inpatient Treatment Phase from Day -1 to Day 2, and Follow-Up 7±2 days after dosing. Up to 80 subjects will be enrolled in up to 10 cohorts of 8 subjects. In each cohort, 6 will receive a single oral dose of psilocybin and 2 matching placebo. The first cohort will receive 0.5 mg psilocybin or placebo. The DSRC will determine subsequent dose levels after each completed cohort. Proposed doses are 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and up to 5 mg; lower doses, repeated levels, or smaller increments such as 0.25 mg may be used based on emerging data. Within each cohort, safety and pharmacodynamic data will be collected through 24 hours post dose. Safety monitoring will include adverse events, vital signs, ECGs, laboratory tests, physical examinations, concomitant medications, and C-SSRS results. Pharmacokinetic blood samples will be collected before and after dosing, and blood for possible retrospective pharmacogenetic analysis will be collected on Day -1. Pharmacodynamic assessments will include Alertness/Drowsiness, Agitation/Relaxation, Hallucinations, Any Effects, Bowdle, Bond-Lader, 5D-ASC, and STAI measures. Cognitive and psychomotor testing will include RTI, RVP, and SWM tasks. Pupil diameter will be measured as an objective marker. Other subject-reported effects may be recorded as adverse events at the investigator's discretion. Subjects will be discharged on Day 2 if medically appropriate and will receive a 24-hour/7-day emergency clinic contact number. After each cohort, the DSRC will review available blinded safety and pharmacodynamic data through 24 hours post dose before the next cohort begins. Escalation and any decision to stop will follow prespecified rules. The study aims to identify a safe threshold dose (TD) that does not elicit psychoactive effects. The TD will be the dose immediately before the dose at which escalation stops because of neuropsychiatric adverse events and/or a pharmacodynamic response pattern indicating a dose above the nonpsychoactive level. The study will end when a TD is identified or the 5 mg maximum dose is reached.
Age range
18 Years – 55 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Clinical Safety Event Frequency
Timeframe: Monitoring from dosing through treatment (3 days) and Follow-Up (~1 week).
Clinical Safety Event Severity
Timeframe: Monitoring from dosing through treatment (3 days) and Follow-Up (~1 week).
Clinical Safety Event Relationship to Treatment
Timeframe: Monitoring from dosing through treatment (3 days) and Follow-Up (~1 week).
Vital Signs Heart Rate for Clinical Safety and Tolerability
Timeframe: Vital signs 0.5, 1, 1.5, 2, 3, 6, 8, 10, 12 hours after dose.
Electrocardiogram for Clinical Safety and Tolerability
Timeframe: ECG baseline and 3 and 6 hours after dosing.
Five-Dimensional Altered States of Consciousness Scale
Timeframe: The 5D-ASC will be administered 6 hours following dosing.
State Trait Anxiety Inventory Scale
Timeframe: The STAI will be given at baseline and at the two and six hour time points following dose.
Reaction Time Test Performance
Timeframe: Reaction time test will be given at baseline and at the two and six hour time points following dosing.
Rapid Visual Information Processing Test
Timeframe: Rapid Visual Information Processing test will be given at baseline and at the two and six hour time points following dosing. Performance will be measured as change from baseline across time and to maximum or minimum effect .
Spatial Working Memory
Timeframe: The Spatial Working Memory (SWM) test will be given at baseline and at the two and six hour time points following dosing. Performance will be measured as change from baseline across time.
Perceptual Pharmacodynamic Alertness Drowsiness Visual Analog Scale
Timeframe: The Alertness/Drowsiness VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.
Perceptual Pharmacodynamic Agitation Relaxation Visual Analog Scale
Timeframe: The Agitation/Relaxation VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.
Perceptual Pharmacodynamic Any Drug Effects Visual Analog Scale
Timeframe: The Any Drug Effects VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.
Perceptual Pharmacodynamic Hallucinations Visual Analog Scale
Timeframe: The Hallucainations VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.
Perceptual Pharmacodynamic Bowdle (internal and external perceptions) Visual Analog Scale
Timeframe: The Bowdle VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.
Perceptual Pharmacodynamic Bond-Lader Visual Analog Scale
Timeframe: The Bond-Lader VAS will be given at baseline, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24 hours after dosing.