Posttraumatic Stress Disorder (PTSD)Phase 2PsiVetNCT07792538
Psilocybin-Assisted Psychotherapy for Veterans With PTSD
A Phase 2 study testing Psilocybin-assisted Psychotherapy in people with Posttraumatic Stress Disorder (PTSD), run by ARQ National Psychotrauma Centre at 1 site in Netherlands.
Trial summary
This study will evaluate the feasibility, safety and preliminary efficacy of psilocybin-assisted psychotherapy in military veterans with treatment-refractory posttraumatic stress disorder (PTSD). Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Posttraumatic Stress Disorder (PTSD)
- What is being tested?
- Psilocybin-assisted Psychotherapy
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteNetherlands
- Study dates
- Dec 2026to Dec 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Are between 18 and 70 years old.
- Able to provide written informed consent.
- Fluent in speaking and reading Dutch.
- Is a veteran of the Dutch Armed Forces.
- Able to swallow pills.
- Have a body mass index (kg/m2) of >18.0.
Show all 10Show fewer
- Meet DSM-5 criteria for current PTSD.
- Meet criteria for treatment-refractory PTSD.
- Agree to have study visits audiovisually recorded.
- Able to provide a contact (relative, spouse, close friend, or other support person) who is willing and able to be reached by the investigators in the event of the participant becoming unwell or unreachable.
Who cannot join
- Has a history of any medical condition that could make receiving psilocybin harmful because of temporary increases in blood pressure and heart rate.
- Has a medical or psychiatric condition that could interfere with study participation or pose a risk to the participant's safety or well-being.
- Has uncontrolled hypertension.
- Unable or unwilling to safely taper-off prohibited psychiatric medication.
- Has been exposed to electroconvulsive therapy (ECT) within 12 weeks of enrollment.
- Has any current problem which, in the opinion of the investigator, might interfere with study participation.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site
ARQ National Psychotrauma Centre / ARQ Centrum'45
Oegstgeest, 2342 EG
About this study
Official title: Psilocybin-Assisted Psychotherapy for Posttraumatic Stress Disorder in Military Veterans: A Pilot Feasibility Study
This study will evaluate the feasibility, safety and preliminary efficacy of psilocybin-assisted psychotherapy in military veterans with treatment-refractory posttraumatic stress disorder (PTSD).
Read the detailed description
Posttraumatic stress disorder (PTSD) is a severe and debilitating mental health condition that significantly impacts patients' lives, leading to functional impairments, strained relationships, and high healthcare costs. About half of the patients with PTSD do not benefit from current evidence-based psychotherapy and available pharmacological treatments offer only limited benefits. Therefore, there is a high need for novel therapeutic approaches in the treatment of PTSD.
Psilocybin-assisted psychotherapy is a promising approach combining the pharmacological effects of psilocybin, a serotonergic psychedelic, with psychotherapy. Psilocybin-assisted psychotherapy has shown promising effects in several phase 2 studies in the treatment of mental health conditions such as depression and end-of-life anxiety, with two phase 3 studies underway for treatment-resistant depression. Building on these initial promising results, psilocybin-assisted psychotherapy is increasingly being studied for other psychiatric indications, including PTSD.
Many of psilocybin's potential therapeutic mechanisms appear to be transdiagnostic in nature. For example, studies suggest that psilocybin can enhance introspection, emotional processing, and psychological flexibility, all of which could facilitate psychotherapeutic processes. Psilocybin has also been shown to reduce avoidance and promote neural plasticity and cognitive reappraisal, which could be particularly relevant for addressing core symptoms of PTSD, such as persistent avoidance and rigid negative thought patterns. Furthermore, its ability to foster a sense of connectedness aligns well with the therapeutic need of individuals with PTSD who face challenges related to social isolation.
Preliminary findings from an initial Phase 2 trial suggest that psilocybin-assisted psychotherapy may be safe and associated with clinically meaningful improvements in PTSD symptoms. However, this study differed from the present study in several important aspects. Participants were not required to have had previous unsuccessful evidence-based psychotherapies for PTSD, and psilocybin administration was not embedded within psychotherapeutic treatment. The current open-label pilot study will focus on veterans with treatment-refractory PTSD, a patient population that frequently shows partial or no response to standard evidence-based PTSD treatment. In addition, psilocybin administration will be part of an extensive psychotherapeutic treatment protocol. This study aims to collect data on the feasibility, preliminary efficacy and safety of psilocybin-assisted psychotherapy in this population, to inform a potential future randomized controlled trial.
- Conditions
- Posttraumatic Stress Disorder (PTSD)
- Being tested
- Psilocybin-assisted Psychotherapy
- Keywords
- Psilocybin, PTSD, Veterans, Psilocybin-assisted psychotherapy, Posttraumatic stress disorder, Psychotherapy
- Medical subject headings
- Stress Disorders, Post-Traumatic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Psilocybin-assisted PsychotherapyDrug
Two psilocybin sessions (15 mg psilocybin in the first session; 25 mg psilocybin in the second session) embedded in a psychotherapeutic framework with three preparatory sessions and six integrative sessions.
| Study group | Role | What they receive |
|---|---|---|
| Psilocybin-assisted psychotherapy | Experimental | Psilocybin-assisted psychotherapy Receives: Drug: Psilocybin-assisted Psychotherapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Clinician-Administered PTSD Scale for DSM-5 Revised (CAPS-5-R)
The last month CAPS-5-R is a semi-structured interview that assesses index history of DSM-5-defined traumatic event exposure, including the most distressing event and time since exposure, and rates intrusion symptoms (intrusive thoughts or memories), avoidance, cognitive and mood symptoms, arousal and reactivity symptoms, duration and degree of distress and dissociation. The CAPS-5-R will be administered by a study independent CAPS-5-R rater.
Measured: From Baseline to 1 month after final integrative psychotherapy session
Semi-structured interview
Comprehensive qualitative information about participants' evaluation of the feasibility, acceptability and efficacy of psilocybin-assisted psychotherapy for PTSD will be collected through a semi-structured interview.
Measured: One month after final integrative psychotherapy session
Treatment Acceptability/Adherence Scale Modified (TAAS-M)
A modified 10-item version of the Treatment Acceptability and Adherence Scale (TAAS-M) will be used to describe acceptability and adherence to psilocybin-assisted psychotherapy.
Measured: One month after final integrative psychotherapy session
Feasibility of participant screening and study retention
The feasibility of participant screening and study retention will be assessed by documenting the number and proportion of participants who fail screening, the number and proportion of enrolled participants who discontinue the intervention, and the reasons for screen failure and discontinuation. All measures will be summarized descriptively.
Measured: From screening until one month after the final integrative psychotherapy session.
Concomitant medication use
Concomitant medication use during study participation will be recorded.
Measured: From screening until one month after the final integrative psychotherapy session.
Columbia Suicide Severity Rating Scale (C-SSRS)
The C-SSRS is a clinician-administered measure of suicidal behavior devised to detect potential suicidal thoughts or behaviors during a clinical trial.
Measured: Measured at several timepoints from screening to one month after the final integrative psychotherapy session.
Adverse events
Severity, incidence and frequency of AEs and serious adverse events (SAEs).
Measured: From screening until one month after the final integrative psychotherapy session.
Blood pressure
Systiloc and diastolic blood pressure (mmHg) will be monitored.
Measured: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Heart rate
Heart rate (beats per minute) will be monitored.
Measured: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Body temperature
Body temperature (°C) will be monitored.
Measured: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Secondary outcomes (2)
Sheehan Disability Scale
The Sheehan Disability Scale is a 3-item assessment of functional impairment.
Measured: Change from Baseline to one month after final integrative psychotherapy session
Beck Depression Inventory-II (BDI-II)
The BDI-II is a 21-item self-report measure for depression symptom severity.
Measured: Change from baseline to one month after final integrative psychotherapy session
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Aug 2026
- Study startDec 2026 (estimated)
- Primary completionDec 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Posttraumatic Stress Disorder (PTSD)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- ARQ National Psychotrauma Centre
- Sponsor type
- University, hospital or other
- Collaborators
- National Healthcare System for Veterans / Landelijk Zorgsysteem voor Veteranen (LZV), Leiden University Medical Center
- Responsible party
- Sponsor
- Investigators
- Eric Vermetten, MD, PhD, Principal investigator, Leiden University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07792538
- Sponsor's protocol ID
- 2025-521488-11-00
- Other IDs
- 2025
- Acronym
- PsiVet
- Status last verified
- Aug 2026
- First submitted
- 23 Jul 2026
- Last updated
- 28 Aug 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Psilocybin-Assisted Psychotherapy for Posttraumatic Stress Disorder in Military Veterans: A Pilot Feasibility Study
- ClinicalTrials.gov ID
- NCT07792538
- Acronym / sponsor ID
- PsiVet / 2025-521488-11-00
- Conditions
- Posttraumatic Stress Disorder (PTSD)
- Keywords
- Psilocybin, PTSD, Veterans, Psilocybin-assisted psychotherapy, Posttraumatic stress disorder, Psychotherapy
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- ARQ National Psychotrauma CentreUniversity, hospital or other
- Collaborators
- National Healthcare System for Veterans / Landelijk Zorgsysteem voor Veteranen (LZV), Leiden University Medical Center
- Study start
- Dec 2026 (estimated)
- Primary completion
- Dec 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 28 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the feasibility, safety and preliminary efficacy of psilocybin-assisted psychotherapy in military veterans with treatment-refractory posttraumatic stress disorder (PTSD).
Detailed description
Posttraumatic stress disorder (PTSD) is a severe and debilitating mental health condition that significantly impacts patients' lives, leading to functional impairments, strained relationships, and high healthcare costs. About half of the patients with PTSD do not benefit from current evidence-based psychotherapy and available pharmacological treatments offer only limited benefits. Therefore, there is a high need for novel therapeutic approaches in the treatment of PTSD.
Psilocybin-assisted psychotherapy is a promising approach combining the pharmacological effects of psilocybin, a serotonergic psychedelic, with psychotherapy. Psilocybin-assisted psychotherapy has shown promising effects in several phase 2 studies in the treatment of mental health conditions such as depression and end-of-life anxiety, with two phase 3 studies underway for treatment-resistant depression. Building on these initial promising results, psilocybin-assisted psychotherapy is increasingly being studied for other psychiatric indications, including PTSD.
Many of psilocybin's potential therapeutic mechanisms appear to be transdiagnostic in nature. For example, studies suggest that psilocybin can enhance introspection, emotional processing, and psychological flexibility, all of which could facilitate psychotherapeutic processes. Psilocybin has also been shown to reduce avoidance and promote neural plasticity and cognitive reappraisal, which could be particularly relevant for addressing core symptoms of PTSD, such as persistent avoidance and rigid negative thought patterns. Furthermore, its ability to foster a sense of connectedness aligns well with the therapeutic need of individuals with PTSD who face challenges related to social isolation.
Preliminary findings from an initial Phase 2 trial suggest that psilocybin-assisted psychotherapy may be safe and associated with clinically meaningful improvements in PTSD symptoms. However, this study differed from the present study in several important aspects. Participants were not required to have had previous unsuccessful evidence-based psychotherapies for PTSD, and psilocybin administration was not embedded within psychotherapeutic treatment. The current open-label pilot study will focus on veterans with treatment-refractory PTSD, a patient population that frequently shows partial or no response to standard evidence-based PTSD treatment. In addition, psilocybin administration will be part of an extensive psychotherapeutic treatment protocol. This study aims to collect data on the feasibility, preliminary efficacy and safety of psilocybin-assisted psychotherapy in this population, to inform a potential future randomized controlled trial.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Psilocybin-assisted psychotherapy | Experimental | Drug: Psilocybin-assisted PsychotherapyPsilocybin-assisted psychotherapy |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Are between 18 and 70 years old.
- Able to provide written informed consent.
- Fluent in speaking and reading Dutch.
- Is a veteran of the Dutch Armed Forces.
- Able to swallow pills.
Key exclusion criteria (6 listed)
- Has a history of any medical condition that could make receiving psilocybin harmful because of temporary increases in blood pressure and heart rate.
- Has a medical or psychiatric condition that could interfere with study participation or pose a risk to the participant's safety or well-being.
- Has uncontrolled hypertension.
- Unable or unwilling to safely taper-off prohibited psychiatric medication.
- Has been exposed to electroconvulsive therapy (ECT) within 12 weeks of enrollment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Psilocybin-assisted PsychotherapyTwo psilocybin sessions (15 mg psilocybin in the first session; 25 mg psilocybin in the second session) embedded in a psychotherapeutic framework with three preparatory sessions and six integrative sessions. | Drug | Psilocybin-assisted psychotherapy |
Primary outcome
Clinician-Administered PTSD Scale for DSM-5 Revised (CAPS-5-R)
Time frame: From Baseline to 1 month after final integrative psychotherapy session
The last month CAPS-5-R is a semi-structured interview that assesses index history of DSM-5-defined traumatic event exposure, including the most distressing event and time since exposure, and rates intrusion symptoms (intrusive thoughts or memories), avoidance, cognitive and mood symptoms, arousal and reactivity symptoms, duration and degree of distress and dissociation. The CAPS-5-R will be administered by a study independent CAPS-5-R rater.
Semi-structured interview
Time frame: One month after final integrative psychotherapy session
Comprehensive qualitative information about participants' evaluation of the feasibility, acceptability and efficacy of psilocybin-assisted psychotherapy for PTSD will be collected through a semi-structured interview.
Treatment Acceptability/Adherence Scale Modified (TAAS-M)
Time frame: One month after final integrative psychotherapy session
A modified 10-item version of the Treatment Acceptability and Adherence Scale (TAAS-M) will be used to describe acceptability and adherence to psilocybin-assisted psychotherapy.
Feasibility of participant screening and study retention
Time frame: From screening until one month after the final integrative psychotherapy session.
The feasibility of participant screening and study retention will be assessed by documenting the number and proportion of participants who fail screening, the number and proportion of enrolled participants who discontinue the intervention, and the reasons for screen failure and discontinuation. All measures will be summarized descriptively.
Concomitant medication use
Time frame: From screening until one month after the final integrative psychotherapy session.
Concomitant medication use during study participation will be recorded.
Columbia Suicide Severity Rating Scale (C-SSRS)
Time frame: Measured at several timepoints from screening to one month after the final integrative psychotherapy session.
The C-SSRS is a clinician-administered measure of suicidal behavior devised to detect potential suicidal thoughts or behaviors during a clinical trial.
Adverse events
Time frame: From screening until one month after the final integrative psychotherapy session.
Severity, incidence and frequency of AEs and serious adverse events (SAEs).
Blood pressure
Time frame: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Systiloc and diastolic blood pressure (mmHg) will be monitored.
Heart rate
Time frame: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Heart rate (beats per minute) will be monitored.
Body temperature
Time frame: At several timepoints between screening and one month after the final integrative psychotherapy session, including during psilocybin administration.
Body temperature (°C) will be monitored.
2 secondary outcomes
Sheehan Disability Scale
Time frame: Change from Baseline to one month after final integrative psychotherapy session
Beck Depression Inventory-II (BDI-II)
Time frame: Change from baseline to one month after final integrative psychotherapy session
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Aug 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Eric Vermetten, MD, PhD principal investigator
Leiden University Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Psilocybin-assisted Psychotherapy in people with Posttraumatic Stress Disorder (PTSD), run by ARQ National Psychotrauma Centre at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 28 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Annika Wirsching, MSc (088 330 5699 ext. +31, a.wirsching@arq.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Clinician-Administered PTSD Scale for DSM-5 Revised (CAPS-5-R) (time frame: From Baseline to 1 month after final integrative psychotherapy session). The study lists 10 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Aug 2026.