After undergoing three 90-minute non-drug introductory psychotherapy sessions with a male/female co-therapist team, study participants will undergo two eight-hour long experimental sessions scheduled three to five weeks apart, during which they will randomly receive either 30, 75 or 125 mg MDMA on both occasions, followed by a supplemental dose of half the initial dose. Participants will undergo integrative psychotherapy in between each experimental session, including on the day after each session. Vital signs and psychological distress will be measured throughout each experimental session, and suicidality will be assessed throughout the course of the study. Spontaneously reported side effects will be collected on the day of each experimental session, and for six days afterward. PTSD symptoms, symptoms of depression, general psychological function, posttraumatic growth and quality of sleep will be assessed one month after the second experimental session, and the blind will be broken.