5-HT2A Agonist Psilocybin in the Treatment of Tobacco Use Disorder

June 26, 2026 updated by: Johns Hopkins University
This is a multi-site, double-blind, randomized clinical trial of the 5-HT2A receptor agonist psilocybin for smoking cessation. Four sites with experience in conducting psilocybin research will be involved in this trial: Johns Hopkins University (JHU), the University of Alabama at Birmingham (UAB), and New York University (NYU). The proposed study will treat 66 participants (22 at each site), randomized to receive either: 1) oral psilocybin (30 mg in session 1 and either 30 mg or 40 mg in session 2); or 2) oral niacin (150 mg in session 1 and either 150 mg or 200 mg in session 2), with sessions 1 week apart.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a multi-site, double-blind, randomized clinical trial of the 5-HT2A receptor agonist psilocybin for smoking cessation. The investigators previously conducted an open-label pilot trial (N = 15) of psilocybin paired with cognitive behavior therapy (CBT). Data showed a biologically-verified 7-day point-prevalence abstinence rate of 67% at 12 months and 60% at 2.5 years (continuous abstinence rates: 53% and 47%, respectively). The investigators are now conducting an open-label randomized comparative efficacy trial of psilocybin vs. nicotine patch, both in combination with CBT. Interim results (N = 44; 22 per group) show greater biologically-verified abstinence rates at 12 months for psilocybin: 7-day point-prevalence: 59% vs. 27%; continuous abstinence: 36% vs. 9%. Despite these promising findings, the investigators have yet to conduct a double-blind study of psilocybin for smoking cessation. Furthermore, previous psilocybin study samples have been largely White with higher socioeconomic status (SES). The current trial will address these issues across four sites with experience in conducting psilocybin research: Johns Hopkins, the University of Alabama at Birmingham (UAB), and New York University (NYU). A diverse sample with regard to ethno-racial identity and SES will be recruited at each site. The proposed double-blind study will treat 66 participants (22 at each site), randomized to receive either: 1) psilocybin; 30 mg in session 1 and either 30 or 40 mg in session 2, with sessions 1 week apart; or 2) niacin; 150 mg in session 1 and either 150 mg or 200 mg in session 2, with sessions 1 week apart. Niacin was selected because it has been used as an active placebo in two previous randomized therapeutic trials of psilocybin, and the FDA has informed the investigators that niacin is the FDA's preferred active placebo for psilocybin. CBT will be administered to both groups and will allow the investigators to test psilocybin's efficacy above and beyond an established treatment approach. Biochemically-confirmed 7-day point-prevalence abstinence will be assessed throughout for up to 12 months. The investigators hypothesize that psilocybin (compared to niacin) will cause increased biologically-confirmed 7-day point-prevalence abstinence at 12-month follow-up. Based on pilot data, the investigators will test cognitive/psychological mediators of treatment response. The investigators hypothesize that psilocybin will be associated with improved cognitive control and decreased anticipation of withdrawal relief (from smoking) 1 day after the target quit date, which will be associated with greater 7-day point-prevalence abstinence at 12- month follow-up. This trial will provide a rigorous test of efficacy in a diverse study sample, and test relevant mechanisms, for an innovative smoking cessation treatment showing potential for substantial efficacy.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
66

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Matthew Johnson, Ph.D
  • Phone Number: 410-550-0056
  • Email: mwj@jhu.edu

Study Contact Backup

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • Recruiting
        • University of Alabama at Birmingham
        • Contact:
        • Contact:
        • Principal Investigator:
          • Peter Hendricks, Ph.D.
    • Maryland
      • Baltimore, Maryland, United States, 21224
        • Active, not recruiting
        • Johns Hopkins University School Of Medicine
    • New York
      • New York, New York, United States, 10016
        • Active, not recruiting
        • New York University

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

21 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 21 years old or older
  • Be a daily smoker (minimum of 5 cigarettes/day on a typical day and breath CO of 6 or greater at screening) with multiple unsuccessful previous quit attempts, and report a continued desire to quit smoking
  • Read, write, and speak English
  • Agree to abstain from smoking for the psilocybin/niacin session from 1 hour before psilocybin/niacin administration until at least 8 hours afterward
  • Agree to refrain from using any psychoactive drugs, including alcoholic beverages, within 24 hours of psilocybin/niacin administration
  • Be healthy 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 lab tests. See Exclusion Criteria below for specific ECG and specific blood test criteria

Exclusion Criteria:

  • The use of e-cigarettes or tobacco products other than machine-manufactured combustible cigarettes (e.g., cigarillos) on more than 5 of the previous 30 days
  • Women who are pregnant (positive pregnancy test) or nursing, or are not practicing an effective means of birth control
  • Positive urine drug screen for illicit drugs (excluding cannabis)
  • Positive urine breath test for alcohol. Participants with positive tests will be rescheduled
  • For blood samples, the following lab values will be exclusionary: transaminases greater than x2 the upper limit of normal lab reference range, hemoglobin less than 11 g/d, and creatinine clearance < 40 ml/min using the Cockroft-Gault equation.
  • For ECG screening: The ECG will be read by a cardiologist. Corrected heart rate (QTc) greater than 450 msec will be excluded.
  • Patients who have baseline vital signs that exceed the following measurements will be excluded from participation: Systolic blood pressure (SBP) > 139 mmHG, diastolic blood pressure (DBP)> 89 mmHG, and heart rate of <=95 beats per minute (BPM). The investigators will perform serial heart rate monitoring with 3 total attempts. That is, heart rate must be <=95 bpm on one of these attempts to be included in the study.
  • Currently taking on a regular basis (e.g., daily) antidepressants of any drug class, antipsychotics, or monoamine oxidase inhibitors (MAOIs), or serotonin-acting dietary supplements (e.g., 5-hydroxy- tryptophan, St. John's wort). Currently taking efavirenz, Acetaldehyde dehydrogenase inhibitors such as disulfiram (Antabuse), Alcohol dehydrogenase inhibitors, or uridine diphosphate glucuronosyltransferase 1-9 (UGT1A9) inhibitors or uridine diphosphate glucuronosyltransferase 1-10 (UGT1A10) inhibitors such as phenytoin, regorafenib, eltrombopag. For individuals who have intermittent or "as needed" use of such medications, psilocybin sessions will not be conducted until at least 5 half-lives of the agent have elapsed after the last dose
  • Current use of medications for smoking cessation (i.e., varenicline, nicotine replacement products, bupropion)
  • Current neurological illnesses including, but not limited to, seizure disorders, frequent migraines or on prophylaxis, multiple sclerosis, movement disorders, history of significant head trauma (loss of consciousness > 24 hours), or central nervous system (CNS) tumor
  • Recent (within the past 12 months) or an extensive history of psychedelic use (>20 lifetime uses)
  • Current or past history of meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for Schizophrenia, Psychotic Disorder (unless substance-induced or due to a medical condition), or Bipolar I or II Disorder. Current or past history within the last 5 years of meeting DSM-5 criteria for alcohol or drug use disorder (excluding caffeine and nicotine) or severe major depression
  • Recent (past year) history of suicidal behavior or attempt or high-level current suicidal ideation assessed by the Columbia Suicide Severity Rating Scale (C-SSRS)
  • Have a first- or second-degree relative with schizophrenia, psychotic disorder (unless substance induced or due to a medical condition), or bipolar I or II disorder
  • Currently meets DSM-5 criteria for Dissociative Disorder, Anorexia Nervosa, Bulimia Nervosa, Major Depression, or Post-traumatic Stress Disorder

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Psilocybin
30 mg in session 1 and either 30 mg or 40 mg in session 2, with sessions 1 week apart. Dosing will be based on participants' responses to the Mystical Experiences Questionnaire (MEQ30), taken at the end of their first session. Participants with a score ≥60% of the maximum on the MEQ30 will remain at a dose of 30 mg of psilocybin for the second session. Participants with an MEQ30 score below 60% will receive a dose of 40 mg for the second session.
Drug: Psilocybin
Participants will received two psilocybin sessions, 1 week apart
Other Names:
  • Active Experimental Group
Active Comparator: Niacin
150 mg in session 1 and either 150 mg or 200 mg in session 2, with sessions 1 week apart. Dosing will be based on participants' responses to the Mystical Experiences Questionnaire (MEQ30), taken at the end of their first session. Participants with a score ≥60% of the maximum on the MEQ30 will remain at a dose of 150 mg niacin for the second session. Participants with an MEQ30 score below 60% will receive a dose of 200 mg niacin for the second session.
Drug: Niacin
Participants will received two niacin sessions, 1 week apart
Other Names:
  • Active Comparator Group

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Potential Efficacy (Smoking Cessation)
Time Frame: 12 months
Smoking cessation will be dichotomously coded 7-day point prevalence abstinence at 12-month follow-up. This binary outcome (abstinent versus non-abstinent) will be verified via three measures of recent smoking-(1) timeline follow-back (TLFB), a self-report calendar completed retrospectively by participants indicating the number of cigarettes smoked each day; (2) exhaled carbon monoxide (CO), an objective and biological measure of smoking over approximately the past 24 hours; and (3) urinary cotinine level, an additional biological and objective measure of nicotine exposure and allows for detection of smoking or other nicotine product use over the previous six days. Though these measures are not study outcomes individually, they will verify 7-day point prevalence abstinence at 12-month follow-up - the primary outcome. Specifically, 0 cigarettes reported on the TLFB, breath CO of ≤6 ppm, and urine cotinine levels of <200ng/mL will be considered smoking abstinence.
12 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Prolonged Abstinence
Time Frame: 12 months
A secondary measure of abstinence will be prolonged abstinence, defined as no smoking at all after the target quit date, with the exception that smoking lapses during an initial 2-week grace period after the target quit date are not counted.
12 months
Cognitive control (Multi-Source Interference Task) at Screening (Visit 0)
Time Frame: Approximately 4 weeks prior to the target quit date
The Multi-Source Interference Task is a measure of cognitive control that requires participants to inhibit a prepotent response when engaged in a voluntary task-based action. The Multi-Source Interference Task will be administered at screening - approximately 4 weeks prior to the first psilocybin / niacin session (i.e., 4 weeks prior to the target quit date), and again at Visits 5 and 6.
Approximately 4 weeks prior to the target quit date
Cognitive control (Multi-Source Interference Task) at Visit 5
Time Frame: Approximately 1 day after the target quit date
The Multi-Source Interference Task is a measure of cognitive control that requires participants to inhibit a prepotent response when engaged in a voluntary task-based action. The Multi-Source Interference Task will be administered at Visit 5 - 1 day after the first psilocybin / niacin session (i.e., 1 day after the target quit date), and again at Visit 6.
Approximately 1 day after the target quit date
Cognitive control (Multi-Source Interference Task) at Visit 6
Time Frame: Approximately 2 days after the target quit date
The Multi-Source Interference Task is a measure of cognitive control that requires participants to inhibit a prepotent response when engaged in a voluntary task-based action. The Multi-Source Interference Task will be administered at Visit 6, the day of the second psilocybin / niacin session (i.e., 2 days after the target quit date).
Approximately 2 days after the target quit date
Smoking Urges (Questionnaire on Smoking Urges; Factor 2) at Screening
Time Frame: Approximately 4 weeks prior to the target quit date
The Questionnaire on Smoking Urges is a multidimensional assessment of smoking craving with demonstrated sensitivity to smoking cessation. Participants will respond using a 7-point scale, where 1 = "Strongly Disagree", 4 = "Neither Agree nor Disagree", and 7 = "Strongly Agree". The scale consists of 10 items and scores can range from 10 - 70, with higher scores reflecting stronger urges to smoke.The Questionnaire on Smoking Urges will be administered at screening - approximately 4 weeks prior to the first psilocybin / niacin session (i.e., 4 weeks prior to the target quit date), and again at Visits 5 and 6.
Approximately 4 weeks prior to the target quit date
Smoking Urges (Questionnaire on Smoking Urges; Factor 2) at Visit 5
Time Frame: Approximately 1 day after the target quit date
The Questionnaire on Smoking Urges is a multidimensional assessment of smoking craving with demonstrated sensitivity to smoking cessation. Participants will respond using a 7-point scale, where 1 = "Strongly Disagree", 4 = "Neither Agree nor Disagree", and 7 = "Strongly Agree". The scale consists of 10 items and scores can range from 10 - 70, with higher scores reflecting stronger urges to smoke. The Questionnaire on Smoking Urges will be administered at Visit 5 - 1 day after the first psilocybin / niacin session (i.e., 1 day after the target quit date), and again at Visit 6.
Approximately 1 day after the target quit date
Smoking Urges (Questionnaire on Smoking Urges; Factor 2) at Visit 6
Time Frame: Approximately 2 days after the target quit date
The Questionnaire on Smoking Urges is a multidimensional assessment of smoking craving with demonstrated sensitivity to smoking cessation. Participants will respond using a 7-point scale, where 1 = "Strongly Disagree", 4 = "Neither Agree nor Disagree", and 7 = "Strongly Agree". The scale consists of 10 items and scores can range from 10 - 70, with higher scores reflecting stronger urges to smoke. The Questionnaire on Smoking Urges will be administered at Visit 6, the day of the second psilocybin / niacin session (i.e., 2 days after the target quit date).
Approximately 2 days after the target quit date

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Johns Hopkins University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute on Drug Abuse (NIDA)
University of Alabama at Birmingham
New York University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Matthew Johnson, 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 30, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 7, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 11, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB00326148
  • U01DA052174 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

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