MDMA-Assisted Therapy for Veterans With Moderate to Severe Post Traumatic Stress Disorder

This randomized, double-blind, single-site phase II 2-arm study will compare MDMA-assisted therapy with low dose d-amphetamine-assisted therapy to treat PTSD symptoms in veteran participants aged 18 years and older with PTSD of at least moderate severity, as measured by the change in CAPS-5 total severity score. The study will be conducted in up to N=40 participants from the Greater Los Angeles VA randomized with a 1:1 allocation to Group 1: MDMA-assisted therapy or Group 2: low dose d-amphetamine assisted therapy. For each participant, the study will consist of: * Screening Period: phone screen, informed consent, eligibility assessment, Screening CAPS-5, and Initial Enrollment of eligible participants. * Preparatory Period: medication tapering, three Preparatory Sessions, baseline assessments (including Baseline CAPS-5), leading to Enrollment Confirmation. * Treatment Period: three Experimental Sessions, and three Integrative Sessions following each Experimental Session including CAPS-5 assessments. * Follow-up Period and Study Termination: Primary Outcome CAPS-5 assessment and Study Termination visit.