Psychological Effects of Methylenedioxymethamphetamine (MDMA) When Administered to Healthy Volunteers (MT-2)

Inclusion Criteria: * Are learning to conduct MDMA-assisted psychotherapy or MDMA research through the MDMA Therapy Training Program * 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 * Must provide a contact (relative, spouse, close friend or other caregiver) who is willing and able to be reached by the investigator in the event of an emergency or if the participant is unreachable * Must agree to inform the investigators within 48 hours if any medical conditions occur or medical procedures are planned * If of childbearing potential, must have a negative pregnancy test at study entry and prior to the Experimental Session, and must agree to use adequate birth control through 10 days after the Experimental Session * If nursing, must be willing to dispose of breastmilk from dosing through 5 days after each Experimental Session * Must not participate in any other interventional clinical trials during the duration of the study * Must agree to not operate a vehicle for at least 24 hours after initial drug administration. * Must have transportation available after the Experimental Session and through the following day, for traveling back for the Integrative Session. * Must commit to medication dosing, therapy, and study procedures * Are willing to be contacted via telephone for all necessary telephone contacts. 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 Bazett's 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 * Have symptomatic liver disease * Have history of hyponatremia or hyperthermia * Weigh less than 45 kilograms (kg) * Are pregnant, or are of childbearing potential and are not practicing an effective means of birth control * Have any current problematic patterns of alcohol or other substance use