Group Psilocybin-Assisted Therapy for Post-Traumatic Stress Disorder (GPAT)

This study is a community-informed, pragmatic, open-label, phase 1 clinical trial of group-format psilocybin-assisted therapy (GPAT) for individuals with post-traumatic stress disorder (PTSD). The primary objectives of this phase 1 study are to assess the safety and feasibility of (GPAT) for individuals with (PTSD) and to evaluate preliminary effects on PTSD severity.

Study Overview

• Status: Recruiting
• Conditions: PTSD
• Intervention / Treatment: Drug: Psilocybin

Detailed Description

This study is a community-informed, pragmatic, open-label, phase 1 clinical trial of group-format psilocybin-assisted therapy (GPAT) for individuals with post-traumatic stress disorder (PTSD). The primary objectives of this phase 1 study are to assess the safety and feasibility of (GPAT) for individuals with (PTSD) and to evaluate preliminary effects on PTSD severity.

These will be assessed by the following outcome measures:

• Proportion of participants completing the study protocol
• Incidence of adverse events (AEs), serious adverse events (SAEs) and AEs of special interest using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0
• Mean change in the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and PTSD checklist for DSM-5 (PCL-5). The CAPS-5 and PCL-5 are based on the DSM-5 not the DSM-5-TR.

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Victoria Culkin; Email: vculkin@salud.unm.edu

Study Locations

• United States
  • New Mexico
    • Albuquerque, New Mexico, United States, 87131
      • Recruiting
      • Interdisciplinary Substance Use and Brain Injury (ISUBI)
      • Contact: Victoria Culkin, MA; Phone Number: 505-272-1754; Email: vculkin@salud.unm.edu
      • Contact: Victoria Culkin, MA; Email: vculkin@salud.unm.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

General:

-T+H years of age and <89 years of age

Identify as a member of one of the cohorts to be studied:

• Veteran or first responder
• Female survivor of sexual violence
• Indigenous person
• Not pregnant, planning to become pregnant, or breastfeeding; if able to become pregnant, willing to use reliable form of birth control for the duration of the study
• If needed, ability and willingness to taper and discontinue medications that may interfere with the action of psilocybin
• Ability to read, speak, and understand English
• Ability and willingness to consent to the terms of the study, including attending all trial visits (most of which will occur in a group setting), preparation and
• follow-up sessions, and completing all trial evaluations
• Ability and willingness to swallow capsules

PTSD severity:

• Meet criteria for PTSD, as defined in the DSM-5
• At screening, symptoms of moderate to severe PTSD (PCL-5 score of 34 or greater) present for at least six months

Exclusion Criteria:

• Inability to achieve five days of abstinence from alcohol, non-prescribed opioids, methamphetamines, cocaine, benzodiazepines, or other illicit substances
• Inability or unwillingness to remain abstinent from cannabis use for 24 hours prior to psilocybin dosing session and 12 hours after receiving the dose of psilocybin
• Risk for clinically significant acute withdrawal from any substance that would cause safety concern on the day of dosing
• Any medical condition that would preclude safe participation in the study, including the following, as determined by medical history review, physical examination, electrocardiogram (ECG), and clinical laboratory tests: Pregnancy/breastfeeding

Cardiovascular conditions:

• Uncontrolled hypertension, defined as >140/90 mm Hg at screening or baseline or >145/95 mm Hg on presentation for dosing day assessed on three consecutive blood pressure measurements
• History of myocardial infarction, cardiac ischemia, congestive heart failure, clinically relevant valvular heart disease, or pulmonary hypertension; any other significant history of cardiovascular condition, based on the clinical judgment of the Trial Physician, which would make a participant unsuitable for the trial
• ECG: Clinically significant abnormality (e.g. atrial fibrillation based on judgement of trial physician including prolonged corrected QT interval (QTc> 450 milliseconds (males) or >470 milliseconds (females)
• Poorly controlled diabetes (HbA1c >8.0%; clinically significant hypoglycemia in the past 6 months)

• Neurological conditions (e.g. epilepsy or other seizure disorder) or neurodegenerative disease (e.g., dementia, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis.), or brain tumor that would impact participation in the trial Serious abnormalities of complete blood count or chemistry

  • Severe hepatic impairment
  • Severe renal impairment,
  • Unstable existing thyroid disorder

• Any of the following psychiatric conditions:

  • Active suicidal ideation; history of hospitalization for suicide attempt within the 12 months prior to screening, affirmative responses to C-SSRS questions 4 or 5
  • Confirmed diagnosis of schizophrenia or other psychotic disorder, firstdegree relative with schizophrenia
  • Axis-II diagnosis
• Use of psychedelics (e.g., psilocybin, mescaline, ayahuasca, DMT, LSD, MDMA, or ketamine) resulting in a discrete psychedelic experience in the past six months.

Using daily dose of psilocybin mushrooms at dose <0.2 mg or LSD at <20 mcg per day for <30 days in a year ("microdosing") will not be an exclusion criterion.

However, participants must agree to no further use of psychedelics during this study starting at screening.

• Returning to an unsafe environment and/or inadequate social support-Any other condition, physical or psychological symptom, medication, or other relevant finding prior to randomization that, based on the clinical judgment of trial personnel, would make a participant unsuitable for the trial.-
• Participation in experimental treatment for PTSD or any research studies within 30 days of screening assessment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: GPAT-PTSD	Drug: Psilocybin; Two group-format dosing sessions, scheduled 4 weeks apart, will be held at the ISUBI Center at UNM or a site outside of UNM with DEA approval for psilocybin storage

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of study completion-feasabiity measure	Number of participants that completed the study.	18 weeks after baseline
Clinician-Administered PTSD Scale for DSM-5	The Clinician-Administered PTSD Scale for DSM-5 is a 30-item structured interview that determines a PTSD diagnosis and severity by assessing the frequency and intensity of 20 DSM-5 symptoms. Each symptom is rated on a 0-4 scale (0=absent, 4=extreme), with a total severity score calculated by summing individual item scores. Total Range: 0-80 (sum of 20 items) total scores indicate severity, with higher ratings indicating worse PTSD symptoms.	baseline and 18 weeks
Incidence of adverse events (AEs), serious adverse events (SAEs) and AEs of special interest using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.	adverse event assessment as safety measure	18 weeks after baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Beck Depression Inventory-II	The Beck Depression Inventory-II is a 21-item, 4-point Likert scale (0-3) self-report questionnaire depression assessment with a minimum score of 0 and a maximum score of 63; higher scores indicate greater depression severity.	12 weeks after second psilocybin administration
Hamilton Anxiety Scale	The Hamilton Anxiety Scale is a 14-item clinician-administered tool used to quantify the severity of anxiety symptoms. Each item is scored from 0 (not present) to 4 (very severe), with a total score range of a minimum score of 0 and a maximum score of 56. Higher scores indicate higher anxiety symptoms.	12 weeks after second psilocybin administration
Sheehan Disability Scale	The Sheehan Disability Scale is a 3-item self-reported tool measuring functional impairment in work, social life, and family life, each rated from 0 (not at all) to 10 (extremely). Total scores range from a minimum score of 0 and a maximum score of 30; higher scores indicate greater impairment.	12 weeks after second psilocybin administration
World Health Organization 5-Wellbeing Index	The World Health Organization 5-Wellbeing Index is a 5-item, self-reported questionnaire assessing subjective psychological well-being over the past two weeks. Respondents rate items from 0 ("at no time"), with total raw scores (0-25) multiplied by 4, to generate a final 0-100 score. A maximum score of 100 indicates the best well-being, while a minimum score of 0 indicates the worst.	12 weeks after second psilocybin administration

Collaborators and Investigators

• Sponsor: University of New Mexico

Publications and helpful links

Helpful Links

• GAT Study website at UNM Academic Interest Group for Psychedelic Assisted Therapies

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2026
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: March 18, 2026
• First Submitted That Met QC Criteria: March 27, 2026
• First Posted (Actual): April 1, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Trauma and Stressor Related Disorders; Mental Disorders; Stress Disorders, Traumatic; Stress Disorders, Post-Traumatic; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Alkaloids; Indoles; Indole Alkaloids; Indolizidines; Indolizines; Tryptamines; Psilocybin
• Other Study ID Numbers: 25-570

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: no plans to share IPD

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No