Investigation of Psychedelic Effects in Psychoactive Substances

February 19, 2026 updated by: Johns Hopkins University
The aim of this double-blind, placebo-controlled, within-subjects study is to determine whether other psychoactive substances can produce experiences akin to those seen with classic psychedelics. Screening involves a medical and psychiatric examination, including blood draw, history and physical, interviews, and questionnaires. Eligible participants will then be asked to complete up to 6 experimental drug administration session during which the participants will potentially receive and report on the subjective effects of 6 different psychoactive substances or inactive placebo. Drug assignment for some sessions will be randomized (like flipping a count or rolling a pair of dice), and both participants and study staff will be blind to the drug condition on any given day. Participants will also complete 2 preparation sessions (4 hours total) before the first experimental session, and follow-up visits after each session to discuss and debrief on the participants subjective experience.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Maryland
      • Baltimore, Maryland, United States, 21218
        • Recruiting
        • Johns Hopkins Center for Psychedelic and Consciousness Research
        • Contact:
        • Contact:
        • Principal Investigator:
          • Frederick S. Barrett, PhD
        • Sub-Investigator:
          • Ryan Vandrey, PhD
        • Sub-Investigator:
          • David Wolinsky, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Be 25 to 55 years old
  • BMI between 18 and 34 kg/m2
  • Agree to consume approximately the same amount of caffeine-containing beverage (e.g., coffee, tea) that he/she consumes on a usual morning, before arriving at the research unit on the mornings of drug session days. If the subject does not usually consume caffeinated beverages, he or she must agree not to do so on session days
  • Agree to refrain from using any psychoactive drugs, including alcoholic beverages, within 24 hours of each drug administration. Exceptions include daily use of caffeine and nicotine.
  • Be healthy and psychologically stable as determined by screening for medical problems via a personal interview, a medical questionnaire, a physical examination, an electrocardiogram (ECG), and routine medical blood and urinalysis laboratory tests
  • Agree not to take any PRN prescription medications on the mornings of the sessions unless deemed appropriate by study team.

Exclusion Criteria:

  • Women who are pregnant (as indicated by a positive urine pregnancy test assessed at intake and before each drug session) or nursing; women who are of child-bearing potential and sexually active who are not practicing an effective means of birth control (e.g. oral contraceptives, intrauterine device)
  • Cardiovascular conditions-coronary artery disease, stroke, angina, uncontrolled hypertension, a clinically significant ECG abnormality (e.g., atrial fibrillation), or transient ischemic attack-that in the clinical opinion of the screening physician or mid-level provider would put the participant at an especially high risk for adverse effects from the study.
  • Epilepsy with history of seizures
  • Insulin-dependent diabetes; if taking oral hypoglycemic agent, then no history of hypoglycemia
  • Currently taking on a regular (e.g., daily) basis any medications having a primary centrally acting pharmacological effect on serotonin neurons or medications that are Monoamine oxidase (MAO) inhibitors. For individuals who have intermittent or as needed (PRN) use of such medications, sessions will not be conducted until at least 5 half-lives of the agent have elapsed after the last dose.
  • Use of nonprescription medications, nutritional supplements, or herbal supplements except when approved by the study investigators. Exceptions will be evaluated by the study investigators and will include acetaminophen, non-steroidal anti-inflammatory drugs, and common doses of vitamins and minerals
  • History of meeting Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 criteria for moderate or severe substance use disorder (including alcohol use disorder, but excluding tobacco), requiring that at least one of the endorsed criteria relates to prior loss of control of substance use (e.g. consuming the substance in larger amounts and for a longer amount of time than intended; persistent desire to cut down or regulate use; unsuccessful attempts to stop use; spending a great deal of time obtaining, using, or recovering from the effects of substance use).
  • Active suicidal ideation and/or behavior at time of screening.
  • Psychiatric disorder that in the clinical opinion of the study team would put the participant at an especially high risk for adverse effects from the study.
  • First-degree relative who meets DSM-5 criteria for a Schizophrenia Spectrum or Other Psychotic Disorder (unless disorder is Substance/Medication-Induced Psychotic Disorder or Psychotic Disorder Due to Another Medical Condition), Bipolar I Disorder, or Bipolar II disorder.
  • Enrolled in another clinical trial or have received any drug as part of a research study within 30 days prior to dosing.
  • Known allergy or prior adverse reaction to any of the study drugs judged by the investigator and/or medical staff to put the study volunteer at greater risk.
  • Known allergy or intolerance to nitroglycerin.
  • Concomitant use of any CYP2C9 and CYP3A4 inhibitors.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Participants may receive an inactive placebo during any one of the experimental sessions.
Drug: Placebo
inactive substance
Active Comparator: Psilocybin
Participants may receive varying oral psychoactive doses of psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine)
Drug: Psilocybin
active comparator for psychedelic effects
Experimental: Other psychoactive drugs
Participants may receive varying oral psychoactive doses of ketamine, dextromethorphan (DXM), N,N-dimethyltryptamine (DMT), 3,4-methylenedioxymethamphetamine (MDMA), or delta-9-tetrahydrocannabinol (THC). All dose levels will be limited to doses that have been safely administered within a single day in a laboratory context in the past.
Drug: Ketamine
psychoactive substance
Drug: Dextromethorphan (DXM)
psychoactive substance
Drug: Dimethyltryptamine (DMT)
psychoactive substance
Drug: Methylenedioxymethamphetamine (MDMA)
psychoactive substance
Drug: Tetrahydrocannabinol (THC)
psychoactive substance

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mystical Experience Questionnaire (MEQ-30)
Time Frame: Week 2, Week 7

The MEQ is a 30-item self-report instrument intended to assess psychedelic-specific acute subjective effects of psychoactive drugs. At the end of each experimental session, participants will be instructed to rate each of the items of the MEQ relative to the experiences that the participant encountered during the course of the drug administration session. The total score on all items is then calculated as the primary outcome measure for each experimental session.

Scores range from 0 to 150 on this measure with higher scores reflecting more mystical experience
Week 2, Week 7

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Drug Effects Questionnaire (DEQ)
Time Frame: Week 2, Week 7

The DEQ is a self-report instrument intended to assess a range of psychoactive drug effects. Individual items include ratings of abuse-related drug effects (e.g. drug effect, good effect, bad effect, liking) and behavioral/mood states often associated with drug intoxication. The DEQ will be rated at baseline prior to the first session, and then at the end of each experimental session. The the primary outcomes for each session will be DEQ score change from baseline.

Scores range from 0 to 200 on this measure where 0 is the least impactful effect.
Week 2, Week 7

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Johns Hopkins University

Investigators

  • Principal Investigator: Frederick Barrett, Ph.D., Johns Hopkins University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 5, 2025

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

January 9, 2025

First Submitted That Met QC Criteria

January 13, 2025

First Posted (Actual)

January 14, 2025

Study Record Updates

Last Update Posted (Actual)

February 23, 2026

Last Update Submitted That Met QC Criteria

February 19, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB00376501

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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