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NCT07210112RecruitingPhase 2

Efficacy of Psilocybin and Trazodone Combination in Treatment-resistant Depression: a Randomized Controlled Proof-of-concept Study (PSILOTRAZ)

Source: ClinicalTrials.gov · Last updated 21 Sept 2026

Brief summary (registry, in English)

Psilocybin, a serotonin receptor agonist in the brain, significantly and quickly improves depressive symptoms while inducing profound acute subjective effects. The benefit-risk ratio of psilocybin in treatment-resistant depression seems favorable, but needs to be confirmed. Moreover, the role of 5-HT2A receptors, involved in the psychedelic experience, on the therapeutic efficacy of psilocybin is still poorly understood. For example, pre-administration of trazodone, a 5-HT2A antagonist antidepressant, could annihilate the acute subjective effects of psilocybin without altering its beneficial effects (Rosenblat et al., 2023). We intend to test this hypothesis by comparing, in a randomized, double-blind, placebo-controlled study, the effect of two possible doses of trazodone (total or partial occupancy of 5-HT2A receptors) on the benefit/risk ratio of psilocybin. We hypothesize that the therapeutic effects of psilocybin are partially independent of 5-HT2A receptor activation and thus persist even after total or partial neutralization of its acute subjective effects.

Status (registry)
Recruiting
Phase (registry)
Phase 2
Study type
Interventional
Enrollment
112 (estimated)
First submitted
29 Sept 2025
Start date
30 Jun 2026
Primary completion date
31 Dec 2029
Lead sponsor
Centre Hospitalier St Anne
Diseases
Depression
NCT number
NCT07210112

What you commit to

  • Study type: Interventional · Phase 2
  • Planned participants: 112
  • From 30 Jun 2026 to the primary completion date, 31 Dec 2029
  • 1 site in 1 country
  • Visits and tests: ask the trial team, the registry does not list them

Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.

Who cannot take part

Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.

Prior treatment

  • Patient with a psychiatric decompensation following a previous use of psychedelic substance like LSD;
    • Comorbidities or somatic specificities:
  • Contraindications to MRI;
    • Concomitant therapies:
  • Treatment with buprenorphine or opioids, clonidine, methyldopa, digoxin, Monoamine oxidase inhibitors (MAOI), aldehyde dehydrogenase (ALDH) inhibitors and alcohol dehydrogenase (ADH) inhibitors, St. John's Wort, or warfarin should be discontinued completely before study drug administration;
  • Use of electroconvulsive therapy and/or transcranial magnetic stimulation, during the current depressive episode; or lifetime vagus nerve stimulation, deep brain stimulation, and/or ablative neurosurgery;

Other illness

  • Psychiatric comorbidities known from medical history or identified during inclusion assessment:
  • Bipolar disorder;
  • Personal or family history of psychotic disorder;
  • History of personality disorder;
  • Post-traumatic stress disorder, obsessive-compulsive disorder, eating disorders;
  • Alcohol or substance use disorder in past 12 months or positive urine toxins at time of assessment;
  • Uncontrolled diabetes;
  • Uncontrolled thyroid disorder;
  • Epilepsy;
  • Parkinson's disease treated by selegiline or levodopa;
  • HIV treated by ritonavir and indinavir;
  • Active infection treated by erythromycin;
  • Fungal infection treated by ketoconazole and itraconazole;
  • Persons deprived of their liberty by judicial or administrative decision, persons under compulsory psychiatric care;

Lab values

  • Cardiovascular history (myocardial infarction, stroke, heart rhythm disorder, uncontrolled hypertension, QT interval prolongation, tachycardia and poor cardiovascular health);

Other

  • Schizophrenia and psychosis;
  • Significant suicide risk, as defined by: (a) suicidal ideation as indicated by items 4 or 5 on the C-SSRS within the past six months, at Screening, during the Screening Period, or at Baseline (b) demonstrating suicidal behaviors in the past six months, or; (c). clinical assessment of significant suicidal risk or risk of self-injury during participant interview;
  • Pregnancy and breastfeeding women;
  • 5-HT antagonist treatment2A (including quetiapine, olanzapine, aripiprazole);
  • Lithium treatment;
  • Use of psychedelics (psilocybin, lysergic acid, ayahuasca, mescaline and derivatives) during current episode;
    • Legal status:
  • Persons under legal protection or unable to give consent;
    • Other:
    • \- Any clinical manifestation which, in the opinion of the investigator, may interfere with the interpretation of study results or constitute a health risk to the participant if he or she participates in the study.

Who the study is looking for

  • Patient with major depressive episode without psychotic features according to DSM-5 criteria;
  • Treatment-resistant depressive episode, i.e. failure to respond to at least two lines of antidepressant medication at an adequate dose and for a sufficient period of time (6 weeks according to the MGH-ATRQ);
  • MADRS ≥ 20;
  • Written signed informed consent;
  • Patient covered by the social security system.

Age in the registry: 18 years to - · Sex: All · Does not accept healthy volunteers

Full criteria on ClinicalTrials.gov

Sites (1)

Sites in registry order. Pick your city on the disease page to sort them by distance.

SiteCityCountrySite status
GHU Paris Psychiatrie and Neurosciences
Coordinator of this site? Confirm its status
ParisFranceRecruiting

This page is information, not medical advice. Discuss any trial with your doctor.