Psilocybin IntoxicationPhase 1NCT07877987
The Impact of Dose on the Impairing, Intoxicating, and Abuse-Related Effects of Psilocybin
A Phase 1 study testing 0mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 1mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink and 5mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink in people with Psilocybin Intoxication, run by Johns Hopkins University at 1 site in United States.
Trial summary
This study will evaluate the subjective and behavioral effects of psilocybin relative to placebo and alcohol. Read more about this study
- Who is it for?
- Ages 21 years and olderHealthy volunteers can take part
- Conditions the study is for
- Psilocybin Intoxication
- What is being tested?
- 0mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 1mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink and 5mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Mar 2027to 30 Jun 2030
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Be at least 21 years old,
- Be in good general health based on screening procedures (e.g., physical exam, blood testing, psychiatric evaluation),
- Have vital signs in normal range,
- Have not donated blood in past 30 days,
- Not be pregnant (assessed via blood serum at screening and urinalysis before each study session) or breast feeding (women only),
- Have a body mass index (BMI) in the range of 18 to 36 kg/m2,
- Report using psilocybin at least once in the participant's lifetime, but not in the past month,
- Negative urine test for illicit drug use (not including cannabis) and negative breath alcohol test (0% breath alcohol concentration) at screening and before study sessions.
Who cannot join
- Psychoactive drug use (aside from nicotine, alcohol, caffeine, cannabis) in past month,
- Current use of over the counter (OTC) drugs, supplements/vitamins, or prescription medications that, in the opinion of the investigator or medical staff, will impact the participant's safety,
- History of or current evidence of significant medical condition that would impact participant's safety (e.g., hypertension, epilepsy),
- Evidence of current psychiatric condition (based on MINI),
- Family history of 1st degree relative with psychotic disorder or bipolar 1 disorder,
- Clinical institute withdrawal assessment for alcohol-revised (CIWA-Ar) score >9 (which indicates that severe withdrawal),50
- Enrollment in another clinical trial or receiving of any drug as part of research within past 30 days, and
- Shipley vocabulary score <18 (corresponds to 5th grade reading level).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Johns Hopkins University
Baltimore, Maryland, 21224
Carlos A Zamarripa, PhD, 410-550-6969, czamarr2@jhmi.edu
About this study
This study will evaluate the subjective and behavioral effects of psilocybin relative to placebo and alcohol.
Read the detailed description
This clinical laboratory study will be double-blind, double-dummy, placebo-controlled and will utilize a within-subjects experimental design. Participants will complete 6 outpatient drug administration sessions that will consist of self-administration of oral capsule containing placebo or psilocybin (0, 1, 5, 15, 25mg) and an alcoholic drink containing alcohol to achieve a 0.00% or 0.08% blood alcohol concentration. No drug combinations will be administered during this study. Primary outcomes include performance on cognitive and psychomotor assessments, subjective drug effects, simulated driving performance, and impact on blood pharmacokinetics.
- Conditions
- Psilocybin Intoxication
- Being tested
- 0mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 1mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 5mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 15mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 25mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink
- Keywords
- Psilocybin, Alcohol
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
0mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 0mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC.
1mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 1mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC.
5mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 5mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC.
15mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 15mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC.
25mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 25mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC.
0mg Psilocybin Capsule + 0.08% BAC Alcoholic DrinkDrug
Participants will self-administer a capsule containing 0mg psilocybin and a drink that contains alcohol dosed to 0.08% BAC.
| Study group | Role | What they receive |
|---|---|---|
| 0mg Psilocybin + 0.00% Blood Alcohol Content (BAC) | Placebo comparator | Participants ingest an oral capsule containing 0mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC Receives: Drug: 0mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink |
| 1mg Psilocybin + 0.00% BAC | Experimental | Participants ingest an oral capsule containing 1mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC Receives: Drug: 1mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink |
| 5mg Psilocybin + 0.00% BAC | Experimental | Participants ingest an oral capsule containing 5mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC Receives: Drug: 5mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink |
| 15mg Psilocybin + 0.00% BAC | Experimental | Participants ingest an oral capsule containing 15mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC Receives: Drug: 15mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink |
| 25mg Psilocybin + 0.00% BAC | Experimental | Participants ingest an oral capsule containing 25mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC Receives: Drug: 25mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink |
| 0mg Psilocybin + 0.08% BAC | Active comparator | Participants ingest an oral capsule containing 0mg psilocybin and ingest a beverage containing alcohol dosed to 0.08% BAC Receives: Drug: 0mg Psilocybin Capsule + 0.08% BAC Alcoholic Drink |
What is being measured
The primary outcome is the main question the study is designed to answer.
Driving performance as assessed by standard deviation of lateral position (SDLP)
The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. SDLP (measured in cm) will be determined during each drive. This measure is a composite index of lateral control and incorporates lane weaving, swerving, and over-correcting. SDLP is the gold standard of quantifying the magnitude of driving impairment from drugs and alcohol and has excellent predictive validity to actual driving. Scores range from 0 to no upper limit. Higher scores represent higher magnitude of driving impairment.
Measured: Baseline, 1, 3, 6, and 24 hours post-dosing
Driving performance as assessed by global drive score during the simulated driving task
Driving impairment will be assessed using a composite driving score, with higher scores indicating greater impairment. The composite score is calculated by converting individual driving outcomes (see primary and secondary driving outcomes) into standardized z-scores and averaging these values to generate an overall composite score. Individual z-scores have a mean of 0 and a standard deviation (SD) of 1 in the reference sample used for standardization. The composite score has an expected mean of 0 in the reference sample, while its SD depends on the correlations among the individual driving outcomes and is not necessarily 1.
Measured: Baseline, 1, 3, 6, and 24 hours post-dosing
Total Clues and Cues exhibited during Standardized Field Sobriety Tests (SFSTs)
Total Clues and Cues will be assessed across six field sobriety tests and summed into a single value. The maximum number of possible clues and cues is 29. Greater values indicate greater impairment of behavioral function during field sobriety tests.
Measured: Baseline, 1, 3, 6, and 24 hours post-dosing.
Drug Effect Questionnaire (DEQ) - Feel Drug Effect
The DEQ will be used to obtain subjective ratings of "feel drug effects". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Measured: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
Drug Effect Questionnaire (DEQ) - Drug Liking
The DEQ will be used to obtain subjective ratings of "drug liking". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Measured: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
Drug Effect Questionnaire - Confidence to Drive
The DEQ will be used to obtain subjective ratings of "confidence to drive". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Measured: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
Whole Psilocin Concentrations - THC Concentrations
Blood psilocin concentrations will be measured to assess changing in blood concentrations following drug administration.
Measured: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Oct 2026
- Study start1 Mar 2027 (estimated)
- Primary completion30 Jun 2030 (estimated)
- Study completion30 Jun 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Psilocybin IntoxicationStudies of the same condition, open and under way.
- More trials run by Johns Hopkins UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- All participants will complete all dose conditions (study arms) in a randomized order
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Johns Hopkins University
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Responsible party
- Sponsor
- Investigators
- Carlos A Zamarripa, PhD, Principal investigator, Johns Hopkins University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07877987
- Sponsor's protocol ID
- IRB00527146
- Other IDs
- R01DA066452
- Status last verified
- Oct 2026
- First submitted
- 9 Oct 2026
- Last updated
- 16 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Dose on the Impairing, Intoxicating, and Abuse-Related Effects of Psilocybin
- ClinicalTrials.gov ID
- NCT07877987
- Acronym / sponsor ID
- IRB00527146
- Conditions
- Psilocybin Intoxication
- Keywords
- Psilocybin, Alcohol
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Johns Hopkins UniversityUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- 1 Mar 2027 (estimated)
- Primary completion
- 30 Jun 2030 (estimated)
- Study completion
- 30 Jun 2030 (estimated)
- First posted
- 16 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the subjective and behavioral effects of psilocybin relative to placebo and alcohol.
Detailed description
This clinical laboratory study will be double-blind, double-dummy, placebo-controlled and will utilize a within-subjects experimental design. Participants will complete 6 outpatient drug administration sessions that will consist of self-administration of oral capsule containing placebo or psilocybin (0, 1, 5, 15, 25mg) and an alcoholic drink containing alcohol to achieve a 0.00% or 0.08% blood alcohol concentration. No drug combinations will be administered during this study. Primary outcomes include performance on cognitive and psychomotor assessments, subjective drug effects, simulated driving performance, and impact on blood pharmacokinetics.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 6
- Model description
- All participants will complete all dose conditions (study arms) in a randomized order
| Arm | Type | Receives |
|---|---|---|
| 0mg Psilocybin + 0.00% Blood Alcohol Content (BAC) | Placebo comparator | Drug: 0mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 0mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC |
| 1mg Psilocybin + 0.00% BAC | Experimental | Drug: 1mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 1mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC |
| 5mg Psilocybin + 0.00% BAC | Experimental | Drug: 5mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 5mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC |
| 15mg Psilocybin + 0.00% BAC | Experimental | Drug: 15mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 15mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC |
| 25mg Psilocybin + 0.00% BAC | Experimental | Drug: 25mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 25mg psilocybin and ingest a beverage containing alcohol dosed to 0.00% BAC |
| 0mg Psilocybin + 0.08% BAC | Active comparator | Drug: 0mg Psilocybin Capsule + 0.08% BAC Alcoholic DrinkParticipants ingest an oral capsule containing 0mg psilocybin and ingest a beverage containing alcohol dosed to 0.08% BAC |
Who may qualify
- Ages
- 21 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Be at least 21 years old,
- Be in good general health based on screening procedures (e.g., physical exam, blood testing, psychiatric evaluation),
- Have vital signs in normal range,
- Have not donated blood in past 30 days,
- Not be pregnant (assessed via blood serum at screening and urinalysis before each study session) or breast feeding (women only),
Key exclusion criteria (8 listed)
- Psychoactive drug use (aside from nicotine, alcohol, caffeine, cannabis) in past month,
- Current use of over the counter (OTC) drugs, supplements/vitamins, or prescription medications that, in the opinion of the investigator or medical staff, will impact the participant's safety,
- History of or current evidence of significant medical condition that would impact participant's safety (e.g., hypertension, epilepsy),
- Evidence of current psychiatric condition (based on MINI),
- Family history of 1st degree relative with psychotic disorder or bipolar 1 disorder,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 0mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 0mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC. | Drug | 0mg Psilocybin + 0.00% Blood Alcohol Content (BAC) |
| 1mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 1mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC. | Drug | 1mg Psilocybin + 0.00% BAC |
| 5mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 5mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC. | Drug | 5mg Psilocybin + 0.00% BAC |
| 15mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 15mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC. | Drug | 15mg Psilocybin + 0.00% BAC |
| 25mg Psilocybin Capsule + 0.00% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 25mg psilocybin and a drink that contains alcohol dosed to 0.00% BAC. | Drug | 25mg Psilocybin + 0.00% BAC |
| 0mg Psilocybin Capsule + 0.08% BAC Alcoholic DrinkParticipants will self-administer a capsule containing 0mg psilocybin and a drink that contains alcohol dosed to 0.08% BAC. | Drug | 0mg Psilocybin + 0.08% BAC |
Primary outcome
Driving performance as assessed by standard deviation of lateral position (SDLP)
Time frame: Baseline, 1, 3, 6, and 24 hours post-dosing
The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. SDLP (measured in cm) will be determined during each drive. This measure is a composite index of lateral control and incorporates lane weaving, swerving, and over-correcting. SDLP is the gold standard of quantifying the magnitude of driving impairment from drugs and alcohol and has excellent predictive validity to actual driving. Scores range from 0 to no upper limit. Higher scores represent higher magnitude of driving impairment.
Driving performance as assessed by global drive score during the simulated driving task
Time frame: Baseline, 1, 3, 6, and 24 hours post-dosing
Driving impairment will be assessed using a composite driving score, with higher scores indicating greater impairment. The composite score is calculated by converting individual driving outcomes (see primary and secondary driving outcomes) into standardized z-scores and averaging these values to generate an overall composite score. Individual z-scores have a mean of 0 and a standard deviation (SD) of 1 in the reference sample used for standardization. The composite score has an expected mean of 0 in the reference sample, while its SD depends on the correlations among the individual driving outcomes and is not necessarily 1.
Total Clues and Cues exhibited during Standardized Field Sobriety Tests (SFSTs)
Time frame: Baseline, 1, 3, 6, and 24 hours post-dosing.
Total Clues and Cues will be assessed across six field sobriety tests and summed into a single value. The maximum number of possible clues and cues is 29. Greater values indicate greater impairment of behavioral function during field sobriety tests.
Drug Effect Questionnaire (DEQ) - Feel Drug Effect
Time frame: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
The DEQ will be used to obtain subjective ratings of "feel drug effects". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Drug Effect Questionnaire (DEQ) - Drug Liking
Time frame: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
The DEQ will be used to obtain subjective ratings of "drug liking". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Drug Effect Questionnaire - Confidence to Drive
Time frame: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
The DEQ will be used to obtain subjective ratings of "confidence to drive". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation.
Whole Psilocin Concentrations - THC Concentrations
Time frame: Baseline, 0.5, 1, 1.5, 2, 3, 4, 5, 6, and 24 hours post-dosing.
Blood psilocin concentrations will be measured to assess changing in blood concentrations following drug administration.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Oct 2026.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Carlos A Zamarripa, PhD principal investigator
Johns Hopkins University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing 0mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink, 1mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink and 5mg Psilocybin Capsule + 0.00% BAC Alcoholic Drink in people with Psilocybin Intoxication, run by Johns Hopkins University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 16 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Carlos A Zamarripa, PhD (410-550-6969, czamarr2@jhmi.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Driving performance as assessed by standard deviation of lateral position (SDLP) (time frame: Baseline, 1, 3, 6, and 24 hours post-dosing). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Oct 2026; AzTrials last refreshed its copy on 8 Nov 2026.