Open Label Study of MDMA-assisted Psychotherapy for Treatment of PTSD With Optional fMRI Sub-Study

Inclusion Criteria: 1. Are at least 18 years old 2. Are fluent in speaking and reading the predominantly used or recognized language of the study site 3. Are able to swallow pills 4. Agree to have study visits video-recorded, including Experimental Sessions, Independent Rater assessments, and non-drug psychotherapy sessions 5. Must 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 a participant becoming suicidal or unreachable 6. Must agree to inform the investigators within 48 hours of any medical treatments and procedures 7. People able to become pregnant (PABP) (i.e., assigned female at birth, fertile, following menarche and until becoming post-menopausal unless permanently sterile), must have a highly sensitive negative pregnancy test at study entry and prior to each Experimental Session, and must agree to use adequate birth control through 10 days after the last Experimental Session. Adequate birth control methods include intrauterine device (IUD), injected or implanted hormonal methods, abstinence, oral hormones plus a barrier contraception, vasectomized sole partner. 8. Agree to the following lifestyle modifications: comply with requirements for fasting and refraining from certain medications prior to Experimental Sessions, not enroll in any other interventional clinical trials during the duration of the study, remain overnight at the study site after each Experimental Session and be driven home after, and commit to medication dosing, therapy, and study procedures Exclusion Criteria: 1. Are not able to give adequate informed consent 2. Have any current problem which, in the opinion of the investigator or Medical Monitor, might interfere with participation 3. Would present a serious risk to others as established through clinical interview and contact with treating psychiatrist 4. Require ongoing concomitant therapy with a psychiatric medication (exceptions apply) 5. Weigh less than 48 kilograms (kg) 6. Are pregnant or nursing or are able to become pregnant and are not practicing an effective means of birth control. 7. Have a history of any medical condition that could make receiving a sympathomimetic drug harmful because of increases in blood pressure (BP) and heart rate. 8. Have current alcohol or substance use disorder. 9. Have used Ecstasy (material represented as containing MDMA) more than 10 times within the last 10 years or at least once within 6 months of the first Experimental Session; or have previously participated in a clinical trial conducted by the sponsor.