Clinical and Mechanistic Effects of Psilocybin in Alcohol Addicted Patients

  • End date
    Dec 31, 2023
  • participants needed
  • sponsor
    University of Zurich
Updated on 2 June 2022
psychotropic drugs


Effects of serotonin 2A/1A receptor stimulation by psilocybin on alcohol addicted patients: a randomized double-blind placebo-controlled study


Two billion people globally consume alcohol, leading in 2016 to 2.8 million deaths (5.2% of all deaths) and 99.2 million Disability Adjusted Life Years (DALYs) lost (4.2% of all DALYs). Of all the diseases, conditions, and injuries attributable to alcohol use, alcohol use disorders (AUDs) create the largest health burden globally. However, approved pharmacological treatments for alcoholism are limited in their effectiveness. A recent proof of- concept study testing psilocybin in ten alcohol dependent patients provides encouraging efficacy results and safety data. The investigators, therefore, propose to test the efficacy of psilocybin for treating alcohol use disorder and study its underlying neurobiological mechanisms in a randomized, placebo controlled, double blind study. To evaluate effects of psilocybin on alcohol use behaviour, clinical symptoms, neurocognitive and emotional measures in patients with alcohol use disorder.

The present clinical trial aims at investigation the clinical and mechanistic effects of Psilocybin in Alcohol Addicted Patients.

Patients with alcohol use disorder who have undergone withdrawal treatment within the last 6 weeks will be investigated in a single-centre, double-blind, placebo-controlled, parallel-group design clinical trial contrasting the acute and persisting effects of psilocybin to those of placebo. Patients will be randomly assigned to psilocybin or placebo group with a 1:1 allocation ratio. The study comprises a total of 6 visits during 6 weeks and two follow-up online surveys (3 and 6 months after treatment). In addition, two follow-up surveys that can be completed from home will guarantee monitoring of long-lasting changes in symptomology and ensure all potential side-effects can be captured. On the treatment visit, a single dose of psilocybin (25mg) or placebo will be administered. Patients will be monitored until all effects have worn off.

Condition Alcohol Use Disorder
Treatment Placebo oral capsule, Psilocybin
Clinical Study IdentifierNCT04141501
SponsorUniversity of Zurich
Last Modified on2 June 2022


Yes No Not Sure

Inclusion Criteria

Informed Consent as documented by signature (Appendix Informed Consent Form)
DSM-IV-diagnosis of alcohol use disorder (based on clinical assessment and confirmed by the SCID Interview)
Having undergone withdrawal treatment from alcohol use within 6 weeks prior to enrolment in the study
Drug free from any psychotropic and serotonergic medication for at least five days before administration of the study drug or placebo
No alcohol use between withdrawal treatment and administration of study drug or placebo
Good physical health with no unstable medical conditions, as determined by medical history, physical examination, routine blood labs, electrocardiogram, urine analysis, and urine toxicology
Normal level of language comprehension (German or Swiss- German)
Willing to refrain from drinking caffeinated drinks during the testing days and from consuming psychoactive substances after enrolling in the study and for the remainder of the study
Women of childbearing potential must be using an effective, established method of contraception for the entire study duration, such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices. Note: female participants who are surgically sterilised / hysterectomised or post-menopausal for longer than 2 years are not considered as being of child bearing potential
Have a family member or friend who can pick them up and stay with them overnight after the psilocybin administration sessions (driving is forbidden at drug treatment days)
No further medication is allowed until visit 6, except for emergencies

Exclusion Criteria

Allergy, hypersensitivity, or other adverse reaction to previous use of psilocybin or other hallucinogens
uncorrected Hypertension
Women who are pregnant or breast feeding
Intention to become pregnant during the course of the study
Lack of safe contraception, defined as: Female participants of childbearing potential, not using and not willing to continue using a medically reliable method of contraception for the entire study duration, such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices, or who are not using any other method considered sufficiently reliable by the investigator in individual cases (Female participants who are surgically sterilised / hysterectomised or post-menopausal for longer than 2 years are not considered as being of child bearing potential)
Known or suspected non-compliance
Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant
Previous enrolment into the current study
Enrolment of the investigator, his/her family members, employees and other dependent persons
Lifetime history of bipolar disorder (I, II, not otherwise specified) Lifetime history of schizophrenia, schizoaffective disorder, or psychosis not otherwise specified
History of DSM-IV drug dependence other than alcohol (except for caffeine or nicotine) within two months prior to enrolment
Comorbid Axis I anxiety and depression disorders diagnoses as well as post-traumatic stress disorder will be permitted if they do not require current treatment
Family history of schizophrenia or schizoaffective disorder, or bipolar disorder type 1 (first or second degree relatives)
History of suicidal behaviour or violent behaviour within last 2 years
Lifetime history of hallucinogen use on more than 10 occasions within last 10 years
Getting psychotherapeutic or psychological treatment from third parties during the study is forbidden
Abnormal electrocardiogram
Any unstable illness as determined by history or laboratory tests
BMI <17 or >30
Uncorrected hypo- or hyperthyroidism
Contraindications to magnetic resonance imaging (MRI safety form)
During the study, new use or dose changes of already existing concomitant medication without prior informing the investigators is forbidden
High risk of adverse emotional or behavioural reaction based on investigator's clinical evaluation (e.g., evidence of serious personality disorder, antisocial behaviour, serious current stressors, lack of meaningful social support)
Participation in another study with investigational drug within the 30 days preceding and during the present study
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