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Feasibility and Safety of PEX010 Psilocybin Capsules (5 mg and 25 mg) in Military Veterans with Posttraumatic Stress Disorder

InvestigationalNo placebo
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What is this trial about?

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

The study focuses on Posttraumatic stress disorder, a condition that can cause intense and distressing memories, anxiety, and difficulty sleeping after experiencing traumatic events. Participants will receive a medication that contains psilocybin, a naturally occurring compound derived from certain mushrooms, taken in capsule form along with structured therapy sessions.

The main aim is to find out whether this combined approach is safe, practical, and helpful for veterans whose symptoms have not improved with other treatments.

During the trial, participants will attend several visits over a few months. After an initial screening, they will receive a low dose of the medication followed by a higher dose in separate sessions, each accompanied by a therapist. Between sessions, they will have regular follow‑up appointments to monitor health, discuss experiences, and complete questionnaires about symptoms, mood, and daily functioning.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline assessment

    After enrollment, a comprehensive baseline assessment is performed. this includes collection of medical history, vital signs, and questionnaires that measure the severity of posttraumatic stress disorder and related symptoms.

    The assessment establishes the starting point for all later measurements.

  2. Step 2

    Pre‑dose psychotherapy preparation

    Several individual psychotherapy sessions are scheduled before any medication is taken. the purpose is to prepare for the upcoming psilocybin-assisted sessions and to establish a supportive therapeutic relationship.

  3. Step 3

    First psilocybin session (low dose)

    A single psilocybin capsule containing 5 mg of dry extract is taken orally under clinical supervision.

    The participant is monitored for several hours while vital signs (blood pressure, heart rate, temperature) are recorded before, during, and after the session.

    The low‑dose session is intended to introduce the effects of the medication in a controlled setting.

  4. Step 4

    Integration psychotherapy after low dose

    Following the low‑dose session, the participant attends multiple psychotherapy integration meetings over the next one to two weeks.

    These meetings help process the experience and reinforce therapeutic goals.

  5. Step 5

    Second psilocybin session (high dose)

    A single psilocybin capsule containing 25 mg of dry extract is taken orally under clinical supervision.

    The participant is again monitored for several hours with continuous recording of vital signs.

    The high‑dose session is the central therapeutic intervention of the study.

  6. Step 6

    Integration psychotherapy after high dose

    After the high‑dose session, the participant engages in a series of psychotherapy integration sessions lasting several weeks.

    These sessions support the incorporation of insights gained during the medication experience into daily life.

  7. Step 7

    Mid‑study follow‑up assessments

    At approximately four weeks after baseline, the participant completes follow‑up questionnaires that evaluate changes in posttraumatic stress disorder symptoms, depression, and functional disability.

    Vital signs and any adverse events are also recorded.

  8. Step 8

    Final follow‑up assessment (13 weeks post‑baseline)

    At 13 weeks after baseline, a comprehensive assessment is performed. this includes the same questionnaires used at baseline, as well as the Treatment Acceptability/Adherence Scale and a semi‑structured interview.

    The assessment captures overall change in symptom severity, safety outcomes, and participant satisfaction.

  9. Step 9

    Study completion interview

    The participant takes part in a final interview that explores experiences during the study and overall impressions of the treatment.

    The interview data are used for qualitative analysis of feasibility and acceptability.

Who can join the trial?

5 criteria

  • Be between 18 and 70 years old when you sign the consent form.
  • Have a diagnosis of post‑traumatic stress disorder (PTSD) that meets the official criteria listed in the DSM‑5 (the main handbook doctors use to define mental health conditions) and have had symptoms for at least six months.
  • Score 40 or higher on the PCL‑5 questionnaire (a list of 20 questions that measures how severe PTSD symptoms are). This indicates at least a moderate level of PTSD.
  • Have treatment‑refractory PTSD, meaning the condition has not improved after trying at least two proven (evidence‑based) treatments, and one of those treatments must be a trauma‑focused psychotherapy (therapy that directly works on the traumatic experience) that included at least eight sessions.
  • Be a veteran of the Dutch Armed Forces (have served in the military of the Netherlands).

Who cannot join the trial?

17 criteria

  • Having a current cluster A or B personality disorder (a type of lasting pattern of thoughts and behaviors that can cause problems in daily life).
  • Having uncontrolled severe high blood pressure (blood pressure consistently 160/100 mmHg or higher, or lower but with other heart risk factors).
  • Having any medical condition that could make psilocybin unsafe because it can temporarily raise blood pressure or heart rate, such as a stroke, heart failure, or unstable insulin‑dependent diabetes.
  • Having a current or past primary psychotic disorder, bipolar disorder type 1, or major depressive disorder with psychotic features (serious mental illnesses that can cause loss of touch with reality).
  • Having a first‑degree relative (parent or sibling) with schizophrenia, another psychotic disorder, or bipolar I disorder.
  • Having current anorexia nervosa or bulimia nervosa (eating disorders that involve extreme restriction of food or binge‑eating and purging).
  • Having current dissociative identity disorder (a condition where a person experiences two or more distinct identities).
  • Having a severe alcohol or cannabis use disorder (meeting at least 6 of 11 diagnostic criteria) within the past 12 months, or a moderate disorder (4‑5 criteria) unless in early remission (at least 3 months without symptoms).
  • Having any illicit drug (other than cannabis) or prescription drug use disorder of any severity within the past 12 months.
  • Having a current serious risk of suicide, as determined by a screening interview and the C‑SSRS (a questionnaire that measures suicidal thoughts and actions).
  • Having a recent suicide attempt, preparatory act, or frequent suicidal thoughts that meet specific scores on the C‑SSRS.
  • Having any of the following heart conditions: coronary artery disease, congenital long QT syndrome, cardiac hypertrophy (enlarged heart muscle), cardiac ischemia (reduced blood flow to the heart), congestive heart failure, or a past myocardial infarction (heart attack).
  • Having a fast heart rate (tachycardia) defined as more than 100 beats per minute.
  • Having a significant abnormality on a screening ECG, such as atrial fibrillation, Wolff‑Parkinson‑White syndrome, ventricular tachycardia, or a QTc interval longer than 450 milliseconds.
  • Having an artificial heart valve.
  • Having additional risk factors for a dangerous heart rhythm called Torsade de pointes (for example, heart failure, low potassium levels, or a family history of long QT syndrome).
  • Any other significant current or past cardiovascular condition that the study doctor believes makes participation unsafe.
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Investigated drugs

PEX010 Psilocybin Capsules are oral capsules that contain a dry extract from the mushroom Psilocybe cubensis. The extract is made using methanol as a solvent. The capsules deliver psilocybin, a natural compound that can temporarily change how a person perceives the world, feels emotions, and thinks. In this study the capsules were taken under medical supervision as part of a carefully monitored treatment plan.

The trial also used psychotherapy sessions that were paired with the psilocybin capsules. Trained clinicians provided supportive counseling and helped participants process traumatic memories and emotions. These therapy sessions were designed to be safe, supportive, and to help integrate the experiences from the medication into everyday life, aiming to reduce PTSD symptoms.

What is already known about the treatment

  • PEX010 Psilocybin Capsules (25 mg Psilocybin)

    This oral capsule is taken by swallowing and contains 25 mg of a dry extract from the mushroom Psilocybe cubensis. The product is still investigational and is being studied in clinical trials, not yet approved for regular medical use. It is being tested mainly for treating post‑traumatic stress disorder in veterans. Psilocybin works by briefly stimulating serotonin receptors in the brain, especially the 5‑HT2A type, which can change mood and perception, and it is classified as a serotonergic psychedelic.

  • PEX010 Psilocybin Capsules (5 mg Psilocybin)

    This oral capsule is also swallowed and provides a lower dose of 5 mg of the same mushroom extract. Like the higher‑dose version, it is an experimental drug currently only available in research studies. It is examined for its potential to help relieve symptoms of post‑traumatic stress disorder. The low dose still activates serotonin receptors, leading to subtle changes in brain activity that may support psychotherapy, and it belongs to the same class of serotonergic hallucinogens.

Investigated diseases

Posttraumatic stress disorder - A mental health condition that can develop after a person experiences or witnesses a frightening or dangerous event. It often starts with intense feelings of fear, helplessness, or horror that can linger for weeks or months. Over time, the person may have recurring, unwanted memories or flashbacks of the event, and may try to avoid places, people, or activities that remind them of it. Sleep problems, irritability, and difficulty concentrating are common as the condition continues. The symptoms can become more pronounced during stressful periods and may fluctuate in intensity.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-521488-11-00Protocol codePsiVetEstimated enrolment12 patientsSponsorARQ National Psychotrauma Centrum

sourced from the EU Clinical Trials Register and site verification

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