In this Stress, Trauma, and Resilience (STAR) Seminar, Dr. Alex Kelman and Dr. Jessica Jeffrey will discuss why treatment options for adults with post-traumatic stress disorder (PTSD) are limited and/or with limited efficacy. MDMA-assisted psychotherapy has shown promising results for adults with PTSD (Mitchell et al., 2021). MDMA is thought to catalyze the therapeutic process when used in conjunction with psychotherapy (Mithoefer, 2017). Additionally, MDMA decreases the fear response and lowers levels of defensiveness without blocking access to traumatic memories or preventing genuine emotional experiences (Metzner and Adamson, 2001). Participants are then able to revisit traumatic memories without being overwhelmed by painful emotions. In a recent phase three study, 90 participants were randomized to receive manualized therapy with MDMA or placebo plus supportive therapy (Mitchell et al., 2021). At two months follow-up, 67% of participants in the MDMA-assisted psychotherapy condition no longer met diagnostic criteria for PTSD, as compared to 32% of participants in the control condition (placebo plus supportive therapy). Furthermore, 88% of the participants treated with MDMA had a clinically significant improvement in their symptoms. MDMA was well tolerated and did not induce significant adverse events (Mitchell et al., 2021).