PTSD is a serious debilitating disorder that negatively impacts a person's daily life. PTSD is a stress-related psychiatric condition that may occur following a traumatic event such as war, disaster, sexual abuse, violence, terrorism, and accidents. PTSD negatively impacts a person's daily life, resulting in relationship difficulties, difficulty in finding and maintaining a job, reduced cognitive and psychosocial functioning, substance abuse, high-cost healthcare use, and increased depression and suicide risk. Available PTSD treatments, including medications and therapy, effectively treat only a fraction of people who try them for adequate dose and duration. People with PTSD can be treated with psychotherapies and pharmacotherapies. In the past decade, there has been a growing amount of research into medications and other methods that may augment the effectiveness of psychotherapy for PTSD

3,4-methylenedioxymethamphetamine (MDMA) is a drug that releases serotonin, norepinephrine and dopamine in the brain and indirectly increases levels of the neurohormones oxytocin, arginine vasopressin and cortisol. The combined neurobiological effects of MDMA increase compassion, reduce defenses and fear of emotional injury, and enhance communication and introspection. MDMA produces anxiolytic and prosocial effects, which counteract avoidance and hyperarousal in the context of therapy. A combined treatment of MDMA and psychotherapy may be especially useful for treating PTSD.

This multi-site, double-blind, randomized Phase 3 study assesses the efficacy and safety of MDMA-assisted psychotherapy versus psychotherapy with placebo control in participants diagnosed with at least severe posttraumatic stress disorder (PTSD). The study will be conducted in N ≈ 100 participants. Participants will be enrolled in one of two groups at a 1:1 ratio. A flexible dose of MDMA or placebo, followed by a supplemental half-dose unless contraindicated, is administered during the Treatment Period with manualized psychotherapy in three monthly Experimental Sessions. This ~12-week Treatment Period is preceded by three Preparatory Sessions. During the Treatment Period, each Experimental Session is followed by three Integrative Sessions of non-drug psychotherapy. The Primary Outcome measure is change in Clinician Administered PTSD Scale for DSM 5 (CAPS-5) from Baseline. Exploratory measures will address specific symptoms, or behavior that is sometimes related to PTSD. Drug safety will be assessed by measuring blood pressure, heart rate and body temperature during experimental sessions, collecting adverse events and measuring suicidal thoughts or behaviors with the Columbia Suicide Severity Rating Scale (CSSRS). This study will compare the effects of three manualized Experimental Sessions of psychotherapy supported by assisted by flexible doses of MDMA versus placebo. Initial doses per Experimental Session include 80 mg or 120 mg of MDMA compounded with mannitol and magnesium stearate or placebo alone (mannitol and magnesium stearate), followed 1.5 to 2 hours later by a supplemental half-dose (40 or 60 mg). Total amounts of MDMA to be administered per Experimental Session range from 80 mg to 180