This Phase 2a, open-label, non-randomized, 3-cohort study assesses the feasibility and safety of MDMA-assisted group therapy for the treatment of PTSD in veterans. The study will be conducted in up to N=18 participants, recruited in three cohorts of six participants each and receive therapy sessions throughout their participation in these group cohorts.

To assess the feasibility and safety of MDMA-assisted group therapy for participants with at least moderate PTSD, the sponsor-investigator is conducting a phase 2, open-label, non-randomized, 3-cohort study. This novel treatment package consists of two once-monthly open-label MDMA Sessions combined with non-drug preparatory and integrative therapy administered in both individual and group sessions. The Primary Clinical Outcome measure, the Clinician Administered PTSD Scale (CAPS-5), evaluates changes in PTSD symptom severity and is assessed by a blinded centralized Independent Rater (IR) pool. The therapeutic approach will combine manualized MDMA-assisted therapy for PTSD with group therapy components.

Inclusion Criteria:

• Are at least 18 years old.
• Are a U.S. Military Veteran
• Are fluent in speaking and reading the predominantly used or recognized language of the study site.
• Are able to swallow pills.
• Agree to have study visits recorded, including MDMA Sessions, outcome assessments, and non-drug psychotherapy sessions.
• Must provide a contact who is willing and able to be reached by the investigators in the event of a participant becoming suicidal or unreachable.
• Must agree to inform the investigators within 48 hours of any medical conditions and procedures.
• If able to become pregnant, must have a negative pregnancy test at study entry and prior to each Experimental Session, and must agree to use adequate contraception through 10 days after the last Experimental Session.
• Must not participate in any other interventional clinical trials during the duration of the study.
• Must commit to medication dosing, therapy, and study procedures.
• Have a current PTSD diagnosis at the time of screening.

Exclusion Criteria:

• Are not able to give adequate informed consent.
• Have uncontrolled hypertension.
• Have a marked baseline QTcF interval >450 milliseconds [ms] demonstrated on repeated ECG assessments.
• Have a history of additional risk factors for Torsade de pointes (e.g., heart failure, hypokalemia, family history of Long QT Syndrome).
• Have evidence or history of significant medical disorders.
• Have symptomatic liver or biliary disease.
• Have history of hyponatremia or hyperthermia.
• Weigh less than 48 kilograms (kg).
• Are pregnant or nursing, or are able to become pregnant and are not practicing an effective means of birth control.
• Are abusing illegal drugs or alcohol.

Independent raters for the primary clinical outcome will be blinded to study design and timepoint.