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 (e.g., criminal 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.



Eligible Ages
Over 25 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  • 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 3 community observers to complete community observer forms via telephone around baseline and follow-up assessments.
  • 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.

Exclusion Criteria

  • 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
  • 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)

Study Design

Phase 2
Study Type
Intervention Model
Parallel Assignment
Primary Purpose
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Arm Groups

ArmDescriptionAssigned Intervention
Psilocybin administration
Psilocybin 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.
  • Drug: Psilocybin
    this has been used in treating obsessive-compulsive disorders, cluster headaches, anxiety, and drug dependence.
    Other names:
    • psychedelic compound
Active Comparator
Diphenhydramine administration
Diphenhydramine 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.
  • Drug: Diphenhydramine
    This drug will be used as the control. Diphenhydramine is a histamine blocker.
    Other names:
    • Benadryl

Recruiting Locations

UAB Outpatient Clinical Research Unit
Birmingham, Alabama 35294
Peter S Hendricks, Ph.D.

More Details

University of Alabama at Birmingham

Study Contact

Peter S. Hendricks, Ph.D.

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 guide (Dr. Hendricks) and secondary monitor (Dr. Cropsey); 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 (e.g., insight and reorientation that boost motivation to quit and abstinence self-efficacy, reduction of withdrawal/craving secondary to mood improvement); 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 guide and secondary monitor will be present with participants throughout this session (at least one individual will always be present with the participant, even during brief intervals when the guide or monitor 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). Although no contemporary studies have reported the need for pharmacological intervention, 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 exceed 190 systolic and 100 diastolic.

Sessions will be videotaped and reviewed to verify session procedures.

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 oriented to be emotionally supportive of the participant (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 guide'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 guide for approximately 2 hours to discuss and reflect on their experience. The guide 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 follow-up meeting. A battery of measures will be delivered at these times. At the conclusion of the 6-month assessment meeting, participants will be debriefed.


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.