A Study of Psilocybin for Major Depressive Disorder (MDD)
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ClinicalTrials.gov Identifier: NCT03866174 |
Recruitment Status :
Completed
First Posted : March 7, 2019
Last Update Posted : June 5, 2023
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One hundred participants, ages 21 to 65, who meet Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for major depressive disorder (MDD) will be stratified by study site and randomized with a 1-to-1 allocation under double-blind conditions to receive a single 25 mg oral dose of psilocybin or a single 100 mg oral dose of niacin. Niacin will serve as an active placebo.
The purpose of this study is to evaluate the potential efficacy of a single 25 mg oral dose of psilocybin for MDD compared to the active placebo in otherwise medically-healthy participants, assessed as the difference between groups in changes in depressive symptoms from Baseline to Day 43 post-dose.
Condition or disease | Intervention/treatment | Phase |
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Depressive Disorder, Major | Drug: Psilocybin Drug: Niacin Other: Set and Setting (SaS) Protocol | Phase 2 |
Major depressive disorder (MDD) has become a health crisis of epidemic proportions in the modern world. One in six individuals in the United States will experience an episode of major depression in his or her lifetime, and it is estimated that major depression will rank second after cardiac disease as a cause of international medical morbidity by the year 2020. Depression is associated with greater disability than are most other chronic illnesses and is a risk factor for mortality. Additionally, depression predicts the later development of a number of medical conditions, including cardiac and cerebrovascular disease, hypertension, diabetes, obesity, metabolic syndrome, dementia, and cancer. Unfortunately, most patients with depression do not experience a complete resolution of symptoms with antidepressant treatment. Partial-but incomplete-response to antidepressants is associated with an increased risk of full symptomatic relapse (even when on therapy) and a worse long-term disease course. Combined with the high prevalence and significant disability associated with MDD, the fact that currently available treatments are not fully adequate highlights the tremendous need to identify novel treatment strategies.
Data suggest that psilocybin may have behavioral effects relevant to the treatment of depression and recent studies also suggest that psilocybin may possess antidepressant properties. To further assess the effects of psilocybin on MDD signs and symptoms, this trial will enroll 100 participants, ages 21 to 65, who meet criteria for MDD. Participants will be stratified by study site and randomized with a 1-to-1 allocation under double-blind conditions to receive a single 25 mg oral dose of psilocybin or a single 100 mg oral dose of niacin. Niacin will serve as an active placebo.
To enhance participant safety, a Set and Setting (SaS) protocol will be utilized similar to the protocol that has been used in all modern studies of psilocybin. The SaS protocol for this study includes: 1) a period of preparation with session Facilitators prior to dosing; 2) administration of study medications in an aesthetically pleasing room under the supervision of two Facilitators who are present throughout the session; and 3) three post-dose integration sessions during which participants are encouraged to discuss their intervention experience with the Facilitators. The SaS protocol will be identical for those randomized to psilocybin or active placebo.
The primary objective of this study is to evaluate the potential efficacy of a single 25 mg oral dose of psilocybin for MDD compared to the active placebo (niacin), assessed as the difference between groups in changes in depressive symptoms from Baseline to Day 43 post-dose.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 104 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Triple (Participant, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Randomized, Double-Blind, Support-of-Concept Phase 2 Study of Single-Dose Psilocybin for Major Depressive Disorder (MDD) |
Actual Study Start Date : | October 15, 2019 |
Actual Primary Completion Date : | June 28, 2022 |
Actual Study Completion Date : | June 28, 2022 |

Arm | Intervention/treatment |
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Experimental: Psilocybin
Participants will receive a single 25 mg dose of psilocybin along with the Set and Setting (SaS) protocol. Psilocybin is administered orally as a capsule and taken with water.
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Drug: Psilocybin
The psilocybin used in this study is synthetically manufactured in a laboratory and meets quality specifications suitable for human research use. The active drug is encapsulated using a hydroxypropyl methylcellulose (HPMC) capsule and contains 25 mg of psilocybin.
Other Name: Psilocybine, Psilocibin, Indocybin Other: Set and Setting (SaS) Protocol The SaS Protocol prescribes 6-8 hours of preparatory meetings with two facilitators prior to dosing, a 7-10 hour dosing session in a comfortable room under the supervision of the same two facilitators, and 4 hours of post-dose integration sessions with facilitators. During the dosing session participants are encouraged to wear eyeshades and listen to a curated playlist on headphones. |
Active Comparator: Niacin
Participants will receive a single 100 mg dose of niacin along with the Set and Setting (SaS) protocol. Niacin is administered orally as a capsule and taken with water.
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Drug: Niacin
The active placebo is encapsulated using a HPMC capsule and contains 100 mg of pharmaceutical grade niacin.
Other Name: Vitamin B3 Other: Set and Setting (SaS) Protocol The SaS Protocol prescribes 6-8 hours of preparatory meetings with two facilitators prior to dosing, a 7-10 hour dosing session in a comfortable room under the supervision of the same two facilitators, and 4 hours of post-dose integration sessions with facilitators. During the dosing session participants are encouraged to wear eyeshades and listen to a curated playlist on headphones. |
- Change in central rater Montgomery-Asberg Depression Rating Scale (MADRS) total score from Baseline to post-dose Day 43 [ Time Frame: Baseline; Day 43 post-dose ]The MADRS is a clinician-rated scale designed to measure depression severity and to detect changes due to antidepressant treatment. The scale consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition. The total (composite) MADRS score is used as the endpoint.
- Change in central rater MADRS score from Baseline to post-dose Day 8 [ Time Frame: Baseline, Day 8 post-dose ]The MADRS is a clinician-rated scale designed to measure depression severity and to detect changes due to antidepressant treatment. The scale consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition. The total (composite) MADRS score is used as the endpoint.
- Change in on-site rater administered Sheehan Disability Scale (SDS) score from Baseline to post-dose Day 43 [ Time Frame: Day 8, 15, 29, and 43 post-dose ]The SDS is a composite of three self-rated items designed to measure the extent to which three major sectors in the patient's life are impaired by psychiatric symptoms, including depression.
- Sustained depressive symptom response defined as a ≥ 50% reduction from Baseline central rater MADRS score at all post-dose assessments [ Time Frame: Day 8, 15, 29, and 43 post-dose ]The MADRS is a clinician-rated scale designed to measure depression severity and to detect changes due to antidepressant treatment. The scale consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition. The total (composite) MADRS score is used as the endpoint.
- Sustained depressive symptom remission defined as a central rater MADRS total score ≤ 10 at all post-dose assessments [ Time Frame: Day 8, 15, 29, and 43 post-dose ]The MADRS is a clinician-rated scale designed to measure depression severity and to detect changes due to antidepressant treatment. The scale consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition. The total (composite) MADRS score is used as the endpoint.

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Ages Eligible for Study: | 21 Years to 65 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- 21 to 65 years old
- Able to swallow capsules
- If of childbearing potential, agree to practice an effective means of birth control throughout the duration of the study
- Have an identified support person and agree to be accompanied home by that person following dosing
- Have sustained moderate-severe depression symptoms at Screening and Baseline
- Meet DSM-5 criteria for a diagnosis of major depressive disorder and are currently experiencing a major depressive episode of at least a 60-day duration at the time of screening
Exclusion Criteria:
- Women who are pregnant or who intend to become pregnant during the study or who are currently nursing
- Have any of the following cardiovascular conditions: uncontrolled hypertension, coronary artery disease, congenital long QT syndrome, cardiac hypertrophy, cardiac ischemia, congestive heart failure, myocardial infarction, tachycardia, artificial heart valve, a clinically significant screening ECG abnormality, or any other significant cardiovascular condition
- Have a history of stroke or Transient Ischemic Attack (TIA)
- Have moderate to severe hepatic impairment
- Have epilepsy
- Have insulin-dependent diabetes
- Have a positive urine drug test
- Nicotine dependence that would disallow an individual to be nicotine free for the 7-10 hours during the dosing period
- Meet DSM-5 criteria for schizophrenia spectrum or other psychotic disorders, including major depressive disorder with psychotic features, or Bipolar I or Bipolar II Disorder
- Meet DSM-5 criteria for antisocial personality disorder
- Meet DSM-5 criteria for a moderate or severe alcohol or drug use disorder

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03866174
United States, California | |
University of California, San Francisco | |
San Francisco, California, United States, 94121 | |
Pacific Neuroscience Institute | |
Santa Monica, California, United States, 91404 | |
United States, Connecticut | |
Yale University | |
New Haven, Connecticut, United States, 06520 | |
United States, Florida | |
Segal Trials | |
Lauderhill, Florida, United States, 33319 | |
United States, Georgia | |
Emory University | |
Atlanta, Georgia, United States, 30322 | |
United States, Illinois | |
Great Lakes Clinical Trials | |
Chicago, Illinois, United States, 60640 | |
United States, Maryland | |
Johns Hopkins University | |
Baltimore, Maryland, United States, 21229 | |
United States, New Jersey | |
Hassman Research Institute | |
Berlin, New Jersey, United States, 08009 | |
United States, New York | |
New York University School of Medicine | |
New York, New York, United States, 10016 | |
United States, Utah | |
Cedar Clinical Research | |
Draper, Utah, United States, 84020 | |
United States, Wisconsin | |
University of Wisconsin - Madison | |
Madison, Wisconsin, United States, 53706 |
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Usona Institute |
ClinicalTrials.gov Identifier: | NCT03866174 |
Other Study ID Numbers: |
PSIL201 |
First Posted: | March 7, 2019 Key Record Dates |
Last Update Posted: | June 5, 2023 |
Last Verified: | May 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Psilocybin, Psychedelics, Depression, MDD |
Depressive Disorder Depression Depressive Disorder, Major Psilocybin Mood Disorders Mental Disorders Behavioral Symptoms Niacin Vitamins Micronutrients |
Physiological Effects of Drugs Vitamin B Complex Hypolipidemic Agents Antimetabolites Molecular Mechanisms of Pharmacological Action Lipid Regulating Agents Vasodilator Agents Hallucinogens Psychotropic Drugs |