Participants who received 30 or 75 mg MDMA may take part in an open-label crossover segment that will follow nearly identical procedures, except that there will only be one introductory session prior to the first experimental session. There will be three experimental sessions. Symptoms of PTSD, depression and posttraumatic growth will be assessed at the start of the study. They will also be assessed one month after the second and two months after the third experimental session.