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Study of Psilocybin for Patients with Treatment-Resistant Depression

InvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a treatment for treatment-resistant depression. This condition occurs when a person with depression does not respond adequately to at least two different types of antidepressant medications. The treatment being tested in this study is a substance called psilocybin, which is administered in the form of a hard capsule taken orally.

The purpose of the study is to evaluate how effective psilocybin is in treating individuals with treatment-resistant depression. Participants in the study will receive psilocybin over a period of four weeks. The study will monitor changes in the severity of depression symptoms, using a standard questionnaire called the Beck Depression Inventory II, one week after the treatment period ends.

Psilocybin is a chemical substance that is being researched for its potential therapeutic benefits in mental health conditions. The study aims to provide insights into whether psilocybin can offer relief for those who have not found success with traditional antidepressant treatments. The trial is expected to continue until 2026, allowing researchers to gather comprehensive data on its effects.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    An initial assessment is conducted to confirm eligibility for the study. This includes verifying a history of severe depression that has not improved with at least two different antidepressant treatments.

    Participants must be between 25 and 65 years old.

  2. Step 2

    Beginning of treatment

    The treatment involves the administration of psilocybin, a substance given in the form of a hard capsule.

    The medication is taken orally.

  3. Step 3

    Treatment duration

    The administration of psilocybin continues for a period of 4 weeks.

    The specific dosage and frequency of administration are determined by the study protocol and communicated to participants during the trial.

  4. Step 4

    Evaluation of treatment efficacy

    One week after the completion of the 4-week treatment period, the severity of depression is assessed.

    This assessment is conducted using the Beck Depression Inventory II, a questionnaire that measures the intensity of depression.

  5. Step 5

    End of trial

    The trial is estimated to conclude by May 30, 2026.

    Participants are informed of the results and any further steps, if applicable, at the end of the study.

Who can join the trial?

4 criteria

  • Both male and female patients can participate.
  • Participants must have a severe depressive episode. This means they are experiencing intense feelings of sadness or hopelessness.
  • Participants must have treatment-resistant depression. This means they have tried at least two different antidepressant medications, but their symptoms did not improve by at least 50%.
  • Participants must be between the ages of 25 and 65 years.

Who cannot join the trial?

3 criteria

  • Individuals who are not diagnosed with treatment-resistant depression cannot participate. This means the study is only for those whose depression has not improved with other treatments.
  • People who are younger than 18 years old or older than 65 years old are not eligible to join the study.
  • Participants must not belong to any vulnerable population groups. This refers to groups of people who might need special protection or care.
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Investigated drugs

Psilocybin is being studied for its potential to help people with depression that hasn't improved with other treatments. It is a substance found in certain types of mushrooms and is being tested to see if it can improve mood and mental health in people who have not responded to traditional depression therapies.

What is already known about the treatment

Psilocybin – Psilocybin is administered orally, typically in the form of capsules or tablets. It is currently being studied in clinical trials for its potential use in treating treatment-resistant depression. The main therapeutic indication is to alleviate symptoms in individuals who have not responded to traditional depression treatments. At the molecular level, psilocybin is believed to work by interacting with serotonin receptors in the brain, which may help to reset or alter neural pathways associated with mood regulation. It is classified as a psychedelic compound, and its use in medicine is still under investigation, with ongoing research to better understand its safety and efficacy.

Investigated diseases

Treatment-resistant depression – Treatment-resistant depression is a form of major depressive disorder that does not respond to standard treatments, such as antidepressant medications and psychotherapy. Individuals with this condition continue to experience persistent depressive symptoms despite trying multiple treatment options. The progression of this disease can involve ongoing feelings of sadness, hopelessness, and a lack of interest in daily activities. It may also include physical symptoms like changes in appetite or sleep patterns. The condition can significantly impact a person's ability to function in daily life. Managing this type of depression often requires exploring alternative therapeutic approaches.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-518654-16-01Estimated enrolment30 patientsSponsorLKH Graz II

sourced from the EU Clinical Trials Register and site verification

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