To ensure every study volunteer is safely evaluated in the trial, the study staff will meet with them to ask questions about their medical and psychiatric history. This is called screening. Potential volunteers will need to provide medical records, have blood drawn, and visit with a study cardiologist. If the volunteer is eligible for the study, they will meet with the study therapists for psychotherapy 15 times over about 4-5 months. There will be three day-long therapy sessions (with MDMA or placebo) and 12 other therapy sessions that are 1.5 hours long. Throughout the study, volunteers will complete questionnaires about how they are doing and meet throughout the study with qualified researchers over telemedicine (video) who will ask questions about their symptoms. At the end of the study, the study therapists and volunteer will meet one final time.