MDMA-Assisted Psychotherapy in People With Posttraumatic Stress Disorder

Inclusion Criteria: * Have current PTSD (within the past 6 months) in response to crime victimization, including childhood sexual or physical abuse, or meet criteria for PTSD in response to combat; * Have a CAPS score showing moderate to severe PTSD symptoms; * They must either: 1. Have had at least one unsuccessful attempt at treatment for PTSD with a SSRI and psychotherapy; 2. Be a veteran with PTSD symptoms that have endured for no less than one year but no more than five years * Be at least 18 years old; * Must be generally healthy; * Willing to remain overnight at the study site; * Agree to have transportation home the morning after experimental sessions; * Are willing to be contacted via telephone for all necessary telephone contacts; * Must have a negative pregnancy test if able to bear children and agree to use an effective form of birth control; * Are proficient in reading English; Exclusion Criteria: * Are pregnant or nursing, or are able to bear children and are not practicing an effective means of birth control; * Weigh less than 50 kg or more than 105 kg; * Are unable to give adequate informed consent; * Prior use of "Ecstasy" (illicit drug preparations purported to contain MDMA) more than 5 times or at any time within the previous 6 months; * Have a history of certain excluded medical disorders.