Published on
November 17, 2022

Second MAPS-Sponsored Phase 3 Trial of MDMA-Assisted Therapy for PTSD Completed

  • MAPS began sponsorship of clinical trials of MDMA-assisted therapy for PTSD in 2000
  • The second Phase 3 trial of any psychedelic-assisted therapy was recently completed when the final participant had their final evaluation session with an Independent Rater
  • With completion, the most advanced clinical research program in psychedelic-assisted therapies is expected to lead to FDA evaluation of the treatment’s safety and efficacy in 2023

MAPS Public Benefit Corporation (MAPS PBC) has announced that the final participant in the second Phase 3 trial of psychedelic-assisted therapy, A Multi-Site Phase 3 Study of MDMA-Assisted Therapy for PTSD (MAPP2), completed their final session in the clinical trial treatment protocol. The clinical trial program for the Breakthrough Therapy has been sponsored by the Multidisciplinary Association for Psychedelic Studies (MAPS) since 2000 and administered by MAPS Public Benefit Corporation (MAPS PBC), a wholly-owned subsidiary of MAPS, since 2014.

"The completion of data gathering in our second Phase 3 study of MDMA-assisted therapy for PTSD is a critical milestone in MAPS’ 36-year campaign to obtain FDA approval for the therapeutic use of MDMA. I’m proud of our team of therapists, staff, donors, funders, and especially the brave patients who volunteered to confront their trauma in our studies. - Rick Doblin, Ph.D., Executive Director, MAPS

The results of the first Phase 3 trial of MDMA-assisted therapy for PTSD, published on May 10, 2021, in Nature Medicine, were statistically significant, with 88% of participants responding to the treatment and a favorable safety profile. A blinded interim analysis of MAPP2 results (as of May 2022), conducted by an independent Data Monitoring Committee, indicated that the trial had a sufficient number of participants, and had at least a 90% probability of obtaining statistical significance (i.e. a one-in-twenty chance that the findings are random).

MAPS recently announced that carefully considered interventions increased ethnoracial diversity among participants in MAPP2. As part of MAPS’ Health Equity Program, MAPS PBC’s researchers implemented solutions to address the health disparities that people of color face within clinical research. Improving the diversity of therapy practitioners and clinical staff, training therapists and independent raters on racial justice and cultural competency, and other interventions in MAPP2 demonstrated a successful framework to address health inequalities in psychedelic-assisted therapies.

The safety and efficacy of psychedelic-assisted therapies are currently under investigation. No psychedelic-assisted therapy has been approved by the FDA or other regulatory authorities; no therapy works for everyone; and all therapies, even in clinical settings, carry risks.


Founded in 1986, MAPS is a 501(c)(3) non-profit research and educational organization that develops medical, legal, and cultural contexts for people to benefit from the careful uses of psychedelics and marijuana. MAPS is sponsoring the most advanced psychedelic therapy research in the world: Phase 3 clinical trials of MDMA-assisted therapy for PTSD. Since MAPS was founded, philanthropic donors and grantors have given more than $130 million for psychedelic and marijuana research and education. MAPS has earned both the Guidestar Platinum Seal of Transparency and a 4-Star Rating from Charity Navigator.