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

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

Status
Not yet recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07210112
Acronym
PSILOTRAZ
Enrollment
112
Registered
2025-10-07
Start date
2025-10-08
Completion date
2030-06-30
Last updated
2025-10-07

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

Conditions

Depression - Major Depressive Disorder, Treatment-resistant Depression (TRD)

Keywords

psilocybin, trazodone, TRD, RCT

Brief summary

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.

Detailed description

Treatment-resistant depression (TRD) is a frequent and potentially severe psychiatric disorder characterized by specific neurocognitive impairments. It has previously been demonstrated that psilocybin, a serotonin receptor agonist in the brain, significantly and quickly improved depressive symptoms while inducing profound acute subjective effects. The benefit-risk ratio of psilocybin in TRD 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 in a randomized, double-blind, placebo-controlled phase II, monocentric, 4 parallel-group proof-of-concept study involving 112 adult subjects with a depressive episode who had failed to respond to at least two lines of antidepressant treatment. Patients will be randomized in a 1:1:1:1 ratio to one of the following treatment groups: * Group 1: Psilocybin PEX010 (25 mg) + trazodone placebo (pharmaceutical master preparation prepared according to GPP) * Group 2: Psilocybin PEX010 (25 mg) + trazodone 5 mg * Group 3: Psilocybin PEX010 (25 mg) + trazodone 30 mg * Group 4: PCB2 (Placebo of PEX010 (25)) + trazodone 30 mg Stratification factors: gender (M/F).

Interventions

DRUGPsilocybin 25 mg per os

Caps of psilocybin administered orally once (V3) under medical and psychologist supervision in group 1, 2, and 3 and in an open-label setting for group 4

DRUGTrazodone 5mg

Oral preparation of trazodone administered orally once (V3) with psilocybin in Group 2

DRUGTrazodone 30 mg

Oral preparation of trazodone administered orally once (V3) with psilocybin in Groups 3 & 4

DRUGPlacebo of psilocybin

Caps of psilocybin placebo will be administered at V3 in group 4

DRUGPlacebo of trazodone

A placebo of trazodone will be administered orally at V3 in group 1

Sponsors

Centre Hospitalier St Anne
Lead SponsorOTHER

Study design

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

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* 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.

Exclusion criteria

Psychiatric comorbidities known from medical history or identified during inclusion assessment: * Bipolar disorder; * Schizophrenia and psychosis; * 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; * 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; * Patient with a psychiatric decompensation following a previous use of psychedelic substance like LSD; Comorbidities or somatic specificities: * Pregnancy and breastfeeding women; * Cardiovascular history (myocardial infarction, stroke, heart rhythm disorder, uncontrolled hypertension, QT interval prolongation, tachycardia and poor cardiovascular health); * 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; * Contraindications to MRI; Concomitant therapies: * 5-HT antagonist treatment2A (including quetiapine, olanzapine, aripiprazole); * Lithium treatment; * 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; * Use of psychedelics (psilocybin, lysergic acid, ayahuasca, mescaline and derivatives) during current episode; Legal status: * Persons deprived of their liberty by judicial or administrative decision, persons under compulsory psychiatric care; * 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.

Design outcomes

Primary

MeasureTime frameDescription
Change from Baseline in the mean score of Montgomery-Åsberg Depression Rating Scale (MADRS) at 1 monthBaseline, Month 1Mean difference of MADRS scores between one month and Baseline, between the following groups: psilocybin + trazodone 30 mg (Group 3) and placebo + trazodone (Group 4).

Secondary

MeasureTime frameDescription
Change from Inclusion in the MADRS scores at Baseline, Day0 H7, Day 1, Day 7, Month 2 and Month 3 in each groupInclusion, Baseline, Day0 H7, Day 1, Day 7, Month 2 and Month 3MADRS scores at Inclusion, Baseline, Day0 H7, Day 1, Day 7, Month 2 and Month 3 in each group
Change from Inclusion in the Beck Depression Inventory (BDI-II) scores at Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3 in each groupInclusion, Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3BDI-II scores at Inclusion, Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3 in each group
Change from Inclusion in the Columbia-Suicide Severity Rating Scale (C-SSRS) scores at Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3 in each groupInclusion, Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3C-SSRS scores at Inclusion, Baseline, Day0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3 in each group
Response rateBaseline, Day 7, Month 1, Month 2 and Month 3Proportion of patients with 50% reduction in MADRS scores in each group at Day 7, Month 1, Month 2 and Month 3 compared to Baseline
Remission rateBaseline, Day 7, Month 1, Month 2 and Month 3Remission rates defined as the proportion of patients with a MADRS score \<10 in each group at Day 7, Month 1, Month 2 and Month 3 compared to Baseline score
Number of adverse events observed including vital signs and clinical laboratory abnormalitiesDay 0, Day 1, Day 7, Month 1, Month 2, Month 3Side effects in all groups between study drug administration at Day 0, Day 1, Day 7, Month 1, Month 2 and Month 3 including vital signs worsening and biological adverse events (laboratory exams worsening)
Change from Inclusion in the mean YMRS at Baseline, Day 0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3Inclusion, Baseline, Day 0 H7, Day 1, Day 7, Month 1, Month 2, Month 3Mean YMRS scores at Inclusion, Baseline, Day 0 H7, Day 1, Day 7, Month 1, Month 2 and Month 3 in each group
Change from Baseline in the MADRS scores at Month1 in the Groups 1, 2 and 4Baseline and Month 1MADRS scores at Baseline and Month 1 in the Groups 1, 2 and 4
Mean score of visual analog scale (VAS) of patients' drug acute subjective effects at Day 0Day 0
Mean scores of Mystical Experience Questionnaire (MEQ30) at Day 0Day 0
Mean score of 5-Dimensional Altered States of Consciousness (5D-ASC) at Day 0Day 0
Mean score of Stanford Expectations of Treatment Scale (SETS) at BaselineBaseline
Mean score of the Credibility/Expectancy Questionnaire (CEQ) at BaselineBaseline
Change from Inclusion in the mean score of Quality of Life in Depression Scale (QLDS) at Baseline, Day 7, Month 1, Month 2 and Month 3Inclusion, Baseline, Day 7, Month 1, Month 2 and Month 3
Change in mean reaction time from Baseline at Day 0, Day 7, Month 1and Month 3Baseline, Day 0, Day 7, Month 1, Month 3
Proportion of patients with a new antidepressant after study treatment administration (Day 0)From Day 0 to end of studyProportion of patients with an introduction of a new antidepressant after Day 0 in each group

Countries

France

Contacts

Primary ContactLucie BERKOVITCH, MD
l.berkovitch@ghu-paris.fr+33 145657481

Outcome results

None listed

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