A Multi-Site Open-Label Extension Study of MDMA-Assisted Psychotherapy for PTSD

Inclusion Criteria: * Were previously enrolled in a parent study and (meet one of the following): 1. At time of unblinding, their treatment assignment was to the placebo arm; or, 2. Did not begin Experimental Sessions due to the COVID-19 global pandemic or other unforeseen circumstances; 3. Completed fewer than three Experimental Sessions prior to Study Termination due to the COVID-19 global pandemic or other unforeseen circumstances. * Are considered in good standing with the study site at which they enrolled in a parent study; if, in the opinion of the investigator, therapy team, and Medical Monitor, the participant was compliant with protocol requirements, even if they were unable to complete all study visits. * Are at least 18 years old * 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, Independent Rater assessments, and non-drug psychotherapy sessions * Must provide a contact (relative, spouse, close friend or other caregiver) 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 of childbearing potential, must have a 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. * Must not participate in any other interventional clinical trials during the duration of the study * Agree to the following lifestyle modifications: comply with requirements for fasting and refraining from certain medications prior to Experimental Sessions. * Must be willing to 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: * Are not able to give adequate informed consent Have uncontrolled hypertension * Have a marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval \>450 milliseconds \[ms\] in males and \>460 ms in females corrected by Fridericia formula) * 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, such as myocardial infarction, cerebrovascular accident, or aneurysm * Have symptomatic liver disease * Have recent history of hyponatremia or hyperthermia * Weigh less than 48 kilograms (kg) * Are pregnant or nursing, or are of childbearing potential and are not practicing an effective means of birth control * Have an active illicit or prescription drug substance use disorder within 12 months