Study of Feasibility and Safety of MDMA-Assisted Group Therapy for the Treatment of PTSD in Veterans

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 Experimental 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.
* 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.
* Have an active illicit drug or prescription drug substance use disorder