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Cocaine-Related DisordersPhase 2NCT02037126

Psilocybin-facilitated Treatment for Cocaine Use

A Phase 2 study testing Psilocybin and Diphenhydramine in people with Cocaine-Related Disorders, run by University of Alabama at Birmingham at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The primary purpose of this study is to evaluate the feasibility and estimate the efficacy of psilocybin-facilitated treatment for cocaine use. We also will monitor the impact of psilocybin-facilitated treatment on the use of other drugs and outcomes relevant to cocaine involvement. Read more about this study

Who is it for?
Ages 25 years and older
Conditions the study is for
Cocaine-Related Disorders
What is being tested?
Psilocybin and Diphenhydramine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
40 participants
Where
1 siteUnited States
Study dates
May 2015to May 2024
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

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 25 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 25 years of age and older
  • Score of at least 3 on the Severity of Dependence Scale
  • Desire to cease cocaine use as indicated by a goal of complete cocaine abstinence on the Thoughts about Abstinence questionnaire
  • Ability to read/write in English
  • No prior hallucinogen use or it will have been at least 3 years since their last use of a hallucinogen
  • Availability of a friend or family member into whose care the participant can be released following their drug administration session.
  • In good general health as assessed by detailed medical history and physical examination
  • Abstinence from cocaine for at least 7 days prior to experimental drug administration as confirmed via urinalysis and no signs of intoxication on other drugs.

Who cannot join

  • 24 years of age and younger
  • Women who are pregnant or breast feeding
  • Current psychiatric diagnoses other than substance abuse/dependence
  • Current hypertension (exceeding 140 systolic and 90 diastolic at resting as described below)
  • Use of tricyclic antidepressants, lithium, Selective Serotonin Reuptake Inhibitors, Monoamine Oxidase Inhibitors, haloperidol, St. John's Wort, or other antipsychotic medications, mood stabilizers, or medications with serotonin activity
  • History of any psychotic disorders
Show all 11Show fewer
  • History of bipolar I or II disorder
  • First or second-degree relatives with any psychotic disorders, or bipolar I or II disorders
  • Current suicidal or homicidal ideation
  • Planning to move from the Birmingham area in the next 6 months
  • Contraindications of MRI (metallic objects in the body, claustrophobia, difficulty with prior MRI)

Trial locations and contacts

1 site in 1 country.

United States1 site
  • UAB Outpatient Clinical Research Unit

    Birmingham, Alabama, 35294

Other trials in United States

About this study

The primary purpose of this study is to evaluate the feasibility and estimate the efficacy of psilocybin-facilitated treatment for cocaine use. We also will monitor the impact of psilocybin-facilitated treatment on the use of other drugs and outcomes relevant to cocaine involvement.

MRI assessment is a unique aspect of this study. As a potential biological mechanism of psilocybin's effect includes changes in default mode network functional connectivity (Carhart-Harris et al., 2012), we will determine if psilocybin's therapeutic effects are mediated by such changes. Moreover, as Glx (a brain metabolite that reflects glutamate) abnormalities have been shown to play a role in cocaine addiction, we will determine if psilocybin impacts Glx in the anterior cingulate cortex and hippocampus.

Read the detailed description

Individuals who are eligible to participate and provide informed consent will complete baseline questionnaires and be randomly assigned in a double-blind manner to the Psilocybin or Active Placebo group. The first MRI assessment will take place shortly thereafter using a 3T head-only Magnetic Resonance Imaging and Spectroscopy scanner (Magnetom Allegra, Siemens medial Solutions, Malvern, PA), optimized for neuroimaging applications.

Preparation sessions (see below) and the drug administration session will take place in a room at the Clinical Research Unit designed to be as comfortable, aesthetically pleasing (i.e., living-room like), and safe (e.g., no furniture with sharp corners or glass objects) as possible, with a directly adjacent, private restroom.

All participants will undergo four weekly preparation sessions of approximately 2 hours each. The purpose of these sessions is to: 1) develop strong therapeutic alliance between the participants and the primary therapist (Dr. Hendricks) and secondary therapist; 2) establish comfort and rapport between participants and the remainder of the research team; 3) discuss participants' aspirations with regard to their drug administration experience (e.g., What do participants hope to gain from their experience?); 4) discuss the treatment rationale and putative mechanisms of action of psilocybin; 5) obtain a detailed personal history of the participant, with a focus on those factors contributing to their current difficulties; 6) prepare participants for drug administration, including a detailed account of all potential effects of the drug; 7) discuss all aspects of the drug administration protocol (i.e., logistics and procedures), including plans of action in the event that participants experience acute distress; and 8) administer cognitive-behavioral treatment for cocaine use. Any participant who demonstrates significant anxiety, discomfort, or unease regarding drug administration at the conclusion of the four preparation sessions will be provided up to two additional preparation sessions. If these sessions are unsuccessful at mitigating the participant's anxiety, discomfort, or unease, the participant will be removed from the study.

Approximately one week after their final preparation session, participants will be instructed to eat a low-fat breakfast prior to presenting for their drug administration session at 8:00 am, approximately 1 hour before drug administration. A urine sample will be collected to verify drug-free status and participants will be encouraged to relax and reflect before drug administration. The drug administration session will take place over the course of 8 hours. The primary and secondary therapists will be present with participants throughout this session (at least one individual will always be present with the participant, even during brief intervals when one of the two therapists may be using the restroom). During this time, participants will be encouraged to lie down, use an eye mask to block external visual distraction, and use headphones through which a supportive music program will be played. Participants will be instructed to focus their attention on their inner experiences throughout the session.

Any participant reporting significant distress will be provided reassurance verbally or physically (e.g., with a supportive touch to the hand or shoulder). In the event that psychological distress is insufficiently managed with reassurance alone, medication will be administered under the guidance of the study physician.

Blood pressure will be assessed at regular intervals via automatic blood pressure monitor (e.g., pre-administration, and at 30, 60, 90, 120, 180, 240, 300, and 360 minutes post-administration), and medication for the treatment of acute hypertension will be administered should blood pressure remain elevated at >200 systolic or >110 diastolic.

Seven hours after drug administration, when the major drug effects have subsided, participants will complete questionnaires assessing their experience. Participants will then be released into the care of a friend or family member (as arranged during preparation sessions) and instructed not to drive an automobile or engage in any other potentially dangerous activity for the remainder of the day. Participants will be provided with the primary therapist's pager number should they feel the need for support that evening.

Within 2 days after the drug administration session, participants will meet with the therapists for approximately 1 hour to discuss and reflect on their experience. The therapists will assess for potential adverse effects at this time. The second MRI session will take place shortly thereafter. Participants will then meet with the guide once per week over the next 4 weeks with an emphasis on integration of their medication session experience in the context of achieving abstinence from cocaine; continued cognitive-behavioral treatment for cocaine use will be provided during these follow-up meetings.

Long-term assessment visits will take place 3 and 6 months after the final therapy meeting. A battery of measures will be delivered at these times. At the conclusion of the 6-month assessment meeting, participants will be debriefed.

Being tested
Psilocybin, Diphenhydramine
Medical subject headings
Cocaine-Related Disorders

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PsilocybinDrug

    Also called psychedelic compound

    this has been used in treating obsessive-compulsive disorders, cluster headaches, anxiety, and drug dependence.

  • DiphenhydramineDrug

    Also called Benadryl

    This drug will be used as the control. Diphenhydramine is a histamine blocker.

Study groups in NCT02037126
Study groupRoleWhat they receive
Psilocybin administrationExperimentalPsilocybin will be administered in pill form at a dose of .36 mg/kg. Psilocybin will be administered in one session over the course of 8 hours.
Receives: Drug: Psilocybin
Diphenhydramine administrationActive comparatorDiphenhydramine will be administered in pill form at a dose of 100 mg. Diphenhydramine will be administered in one session over the course of 8 hours.
Receives: Drug: Diphenhydramine

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percentage of Abstinent Days

    Percentage of days abstinent from cocaine among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview and with biochemically verified cocaine presence as assessed via a urine drug screen.

    Measured: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.

  2. Number of Participants With Complete Abstinence From Cocaine

    Complete abstinence from cocaine among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview and with biochemically verified cocaine presence as assessed via a urine drug screen.

    Measured: From the psilocybin or placebo administration session to 24 weeks after end-of-treatment.

  3. Number of Days to First Use of Cocaine

    Number of days to first use of cocaine after the drug administration session among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview and with biochemically verified cocaine presence as assessed via a urine drug screen.

    Measured: From the psilocybin or placebo administration session to 24 weeks after end-of-treatment.

Secondary outcomes (14)
  1. Severity of Dependence Scale

    Ratings on the Severity of Dependence Scale (SDS) among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. Severity of Dependence Scale (SDS) ratings are the sum of the five item values and range from 0 (indicating no dependence symptoms on the scale) to 15 (indicating the highest level of dependence).

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  2. Cocaine Selective Severity Assessment

    Ratings on the Cocaine Selective Severity Assessment (CSSA) among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo). Ratings range from 0 to 112, reflecting the sum of the individual items. Higher scores indicate greater withdrawal severity.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  3. Cocaine Craving Questionnaire

    Ratings on the Cocaine Craving Questionnaire-Brief (CCQ-B) among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. The Cocaine Craving Questionnaire-Brief (CCQ-B) is a 10-item scale, and mean scores are reported (possible range = 0 to 7), with greater scores representing more craving.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  4. Situational Confidence Questionnaire

    Ratings on the Brief Situational Confidence Questionnaire (BSCQ) among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. A global/average score across the 8 items is calculated, ranging 0-100. Higher scores indicate greater confidence to resist the urge to use cocaine.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  5. Thoughts About Abstinence Questionnaire

    Ratings on the Thoughts About Abstinence Questionnaire among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. The Thoughts About Abstinence Questionnaire captures motivation to quit, confidence in the ability to quit, and perceived difficulty quitting with one item each using a 1 to 10 scale. Greater scores represent greater motivation to quit, confidence in the ability to quit, and perceived difficulty quitting, respectively.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  6. Depression, Anxiety, and Stress Scale

    Ratings on the Depression, Anxiety, and Stress Scale (DASS-21) among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. This questionnaire provides mean scores for depression, anxiety, and stress, with total possible scores ranging from 0 to 3. Greater scores represent more depression, anxiety, and stress, respectively.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  7. Satisfaction With Life Scale

    Ratings on the Satisfaction with Life Scale among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. A sum of the 5 items yields a total score, ranging from 5 to 35. Greater scores represent more satisfaction with life.

    Measured: Within 48 hours after psilocybin or placebo administration, at end-of-treatment (approximately 4 weeks after psilocybin or placebo administration in most participants), at 12 weeks after end-of-treatment, and at 24 weeks after end-of-treatment.

  8. Individual Income

    Responses on a brief demographic questionnaire among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. Income is reported as estimated annual income based on current earnings.

    Measured: At 24 weeks after end-of-treatment.

  9. Employment Status

    Responses on a brief demographic questionnaire among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. Participants reported being unemployed, or not unemployed (employed, retired or on disability, or a student).

    Measured: At 24 weeks after end-of-treatment.

  10. Living Situation

    Responses on a brief demographic questionnaire among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed via self-report. Participants reported having a stable living situation (e.g., living in a house or apartment they owned or rented) an unstable living situation (e.g., experiencing homelessness).

    Measured: At 24 weeks after end-of-treatment.

  11. Percentage of Alcohol Abstinent Days

    Percentage of days abstinent from alcohol among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview.

    Measured: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.

  12. Percentage of Heavy Alcohol Abstinent Days

    Percentage of days abstinent from heavy alcohol use among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview.

    Measured: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.

  13. Percentage of Tobacco Abstinent Days

    Percentage of days abstinent from tobacco among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview.

    Measured: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.

  14. Percentage of Cannabis Abstinent Days

    Percentage of days abstinent from cannabis among subjects in each of the arms (subjects receiving psilocybin and subjects receiving placebo) assessed with the Timeline Followback Interview.

    Measured: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted15 Jan 2014 (estimated)
  2. Study startMay 2015
  3. Primary completionMay 2024
  4. Study completionMay 2024

Resources

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 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
40 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT02037126
Sponsor's protocol ID
IND_121000
Status last verified
Feb 2026
First submitted
13 Jan 2014
Last updated
18 May 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Publications

  • Hendricks PS, Lappan SN, Shelton RC, Lahti AC, Cropsey KL, Johnson MW, Bradley M, Simonsson O, Davis LL, Grossman DH, Ortiz CE. Psilocybin in the Treatment of Cocaine Use Disorder: A Randomized Clinical Trial. JAMA Netw Open. 2026 May 1;9(5):e2611029. doi: 10.1001/jamanetworkopen.2026.11029.

    PubMed 42096204

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Psilocybin and Diphenhydramine in people with Cocaine-Related Disorders, run by University of Alabama at Birmingham 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 11 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: finished, as of the sponsor's last update on 18 May 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. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 18 May 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of Abstinent Days (time frame: From the psilocybin or placebo administration session to end-of-treatment (approximately 4 weeks in most participants), from end-of-treatment to 12 weeks after end-of-treatment, and from 12 weeks after end-of-treatment to 24 weeks after end-of-treatment.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT02037126, which also lists 1 linked publication.

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 18 May 2026; AzTrials last refreshed its copy on 6 Nov 2026.

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