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Psilocybin With Pimavanserin Compared to Psilocybin Alone for the Treatment of Major Depressive Disorder

Investigating the Role of Serotonin in the Mechanism of Action of Psilocybin in Patients With Major Depressive Disorder

Status
Recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06592833
Enrollment
60
Registered
2024-09-19
Start date
2025-02-25
Completion date
2028-03-01
Last updated
2025-05-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Major Depressive Disorder

Brief summary

This is an interventional, parallel arm assignment treatment study in individuals with Major Depressive Disorder (MDD). Each individual will be treated with a single dose of pimavanserin or placebo plus a single dose of psilocybin. Evaluations will be taken before dosing and following dosing at several timepoints up to 5 weeks post-dosing.

Detailed description

In this study, the researchers want to probe the role of the 5-HT2A receptor in mediating the subjective effects of psilocybin. While previous studies have shown that blockage of the 5-HT2A receptor reduces the psychedelic experience in humans, an animal study revealed that blockage of the 5- HT2A receptor abolished the psychedelic effects without affecting the antidepressant response. This suggests that the pathway responsible for the antidepressant response is dissociated from the psychedelic experience pathway, which is mediated by 5-HT2A signaling.

Interventions

DRUGPsilocybin

Psilocybin, 25mg, given once orally.

DRUGPimavanserin

Pimavanserin, 34mg, given once orally

DRUGPlacebo

Matching placebo.

Sponsors

Icahn School of Medicine at Mount Sinai
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
21 Years to 80 Years
Healthy volunteers
No

Inclusion criteria

* Age 21-80 years, any gender * Current primary diagnosis of Unipolar Major Depressive Disorder (MDD) without psychotic features using DSM-5 criteria * 24-item Hamilton Rating Scale for Depression (HRSD) ≥16 * Current diagnosis of Major Depressive Episode (MDE) * Capable of providing informed consent and complying with study procedures * Currently using or agreeing to use a highly effective contraception, if person of childbearing potential (such as condoms, IUD, or oral contraceptive), for duration of the study. Male participants agree to use highly effective contraception with partners of childbearing potential * Discontinuation of any serotonergic drug for at least 2 weeks or 5 half-lives (whichever of the two is longer) prior to psilocybin exposure

Exclusion criteria

* Any severity of substance use disorder in the last 6 months (excluding tobacco use disorder) as determined by DSM-V criteria via the SCID * Current psychiatric hospitalization or psychiatric hospitalization within the last 6 months * Use of psychedelics in the last 12 months * Non-medical or illicit use of ketamine in the past 12 months * Negative reaction after prior use of psychedelics * Past or current psychotic disorder (including psychotic MDD), mania, or bipolar disorder * Severe depression as indicated by Clinical Global Impressions (CGI)-Severity score ≥ 5 at baseline * Significant suicidal ideation as indicated by C-SSRS \> 2 in the past 6 months at time of screening * Suicide attempt in the past 2 years, or clinician concern that the patient poses a risk to self or others * Acute, severe, or unstable medical illness * Weight \> 300 lbs., or girth size incompatible with scanner bore * Any conditions/qualities that make participation in MRI imaging unsafe\* * Any physical or intellectual disability adversely affecting ability to complete assessments. * Current pregnancy or currently breast feeding. * Any clinically significant abnormal lab test result, including clinically significant abnormal baseline liver and/or renal function tests * Currently being treated with a contraindicated medication. Contraindicated medications include antipsychotic medications, serotonergic antidepressant medications, and mood stabilizers that may attenuate the effects of psilocybin. Strong CYP3A4 inhibitors and inducers are also contraindicated. UGT1A9 and UGT1A10 inhibitors, monoamine oxidase, and aldehyde or alcohol dehydrogenase inhibitors are prohibited concomitant medications. * History of abnormal QT prolongation or QTc interval \>450 ms on screening * Use of medications known to prolong the QT interval * Any congenital prolongation of the QT interval or a family history of long QT syndrome * A family history of sudden cardiac or unexplained death * A family history in a first-degree relative of psychosis/schizophrenia or related disorders * A first-degree family history of bipolar disorder * A history of cardiac arrhythmias or who require treatment with an antiarrhythmic medication * A history of any cardiovascular disorder/condition known to increase the possibility of QT prolongation, or any other risk factors for prolonged QT interval/tosades de pointes (including symptomatic bradycardia, hypokalemia, hypomagnesemia, hypocalcemia, heart failure, or Brugada Syndrome) * Preexisting cardiovascular conditions, including cardiac valvulopathy, pulmonary hypertension, hypertension, tachycardia, and any cardiovascular conditions that may be worsened/exacerbated by elevated blood pressure or heart rate. * Baseline vital sign parameters at screening and on day of dosing prior to dose that exceed to the following values for systolic blood pressure (SBP), diastolic (DBP), and heart rate (HR): SBP \> 139 mmHg, DBP 89 mmHg, and HR \> 90 bpm * Hypersensitivity to either psilocybin or pimavanserin * Psychiatric or other condition judged to be incompatible with establishment of rapport with therapy team and/or safe exposure to psilocybin * Positive urine toxicology at screening * Any clinically significant abnormalities on 12-lead electrocardiogram (ECG) * Mini-Mental State Examination (MMSE) score \< 25 * Brief Psychiatric Rating Scale (BPRS-6) \> 5 * Potential fall risk

Design outcomes

Primary

MeasureTime frameDescription
Mystical Experience Questionnaire (MEQ-30) Score6 hours post-treatmentAcute subjective effects of psilocybin measured by the Mystical Experience Questionnaire (MEQ-30). Full Scale ranges from 0 to 150, with higher scores indicating more mystical experience.

Secondary

MeasureTime frameDescription
Montgomery-Åsberg Depression Rating Scale (MADRS) Score7 days after dosingThe Montgomery-Åsberg Depression Rating Scale (MADRS) will be used to measure improvement in depressive symptoms 7 days after dosing. This 10-item clinician-rated scale measures the severity of depressive symptoms. Full scale ranges from 0 to 60, with higher scores indicating more depressive symptoms.

Countries

United States

Contacts

Primary ContactDepression and Anxiety Center Icahn School of Medicine at Mount Sinai
dac@mssm.edu(212) 241-6539

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026