MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study

This double-blind, placebo-controlled study (n=90) finds that MDMA-assisted therapy (3x 80-120mg) is effective (d=.91, large effect size) in the treatment of PTSD. 67% of those in the MDMA-group no longer qualified for PTSD (vs 32% for the therapy-only group). This study is part of the Phase III trial to get MDMA approved by the FDA.


Post-traumatic stress disorder (PTSD) presents a major public health problem for which currently available treatments are modestly effective. We report the findings of a randomized, double-blind, placebo-controlled, multi-site phase 3 clinical trial (NCT03537014) to test the efficacy and safety of 3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy for the treatment of patients with severe PTSD, including those with common comorbidities such as dissociation, depression, a history of alcohol and substance use disorders, and childhood trauma. After psychiatric medication washout, participants (n = 90) were randomized 1:1 to receive manualized therapy with MDMA or with placebo, combined with three preparatory and nine integrative therapy sessions. PTSD symptoms, measured with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5, the primary endpoint), and functional impairment, measured with the Sheehan Disability Scale (SDS, the secondary endpoint) were assessed at baseline and at 2 months after the last experimental session. Adverse events and suicidality were tracked throughout the study. MDMA was found to induce significant and robust attenuation in CAPS-5 score compared with placebo (P < 0.0001, d = 0.91) and to significantly decrease the SDS total score (P = 0.0116, d = 0.43). The mean change in CAPS-5 scores in participants completing treatment was −24.4 (s.d. 11.6) in the MDMA group and −13.9 (s.d. 11.5) in the placebo group. MDMA did not induce adverse events of abuse potential, suicidality or QT prolongation. These data indicate that, compared with manualized therapy with inactive placebo, MDMA-assisted therapy is highly efficacious in individuals with severe PTSD, and treatment is safe and well-tolerated, even in those with comorbidities. We conclude that MDMA-assisted therapy represents a potential breakthrough treatment that merits expedited clinical evaluation.

Authors: Jennifer M. Mitchell, Michael Bogenschutz, Alia Lilienstein, Charlotte Harrison, Sarah Kleiman, Kelly Parker-Guilbert, Marcela Ot’alora G., Wael Garas, Casey Paleos, Ingmar Gorman, Christopher Nicholas, Michael Mithoefer, Shannon Carlin, Bruce Poulter, Ann Mithoefer, Sylvestre Quevedo, Gregory Wells, Sukhpreet S. Klaire, Bessel van der Kolk, Keren Tzarfaty, Revital Amiaz, Ray Worthy, Scott Shannon, Joshua D. Woolley, Cole Marta, Yevgeniy Gelfand, Emma Hapke, Simon Amar, Yair Wallach, Randall Brown, Scott Hamilton, Julie B. Wang, Allison Coker, Rebecca Matthews, Alberdina de Boer, Berra Yazar-Klosinski, Amy Emerson & Rick Doblin


MAPS wrote a press-release about this study (also see the great graphics on the second half of that page).


PTSD, or Post-Traumatic Stress Disorder, is a terrible mental health disease for which there currently is no good treatment option available. The SSRIs currently approved by the FDA (paroxetine and sertraline) don’t help between 40 and 60% of patients. Similarly, the current psychotherapies (e.g. prolonged exposure, CBT) aren’t up to the task.

The pooled analysis of six Phase II trials (n=105, Jerome et al., 2020) has already shown MDMA (in combination with therapy) to possibly be the way to treat PTSD. That study showed CAPS-IV scores (a measure of PTSD) to drop by an average of 45 points, with a further drop of 5 points at the long-term follow-up. At that moment, 67% of participants no longer met the criteria for PTSD.


The current study (n=90) followed a double-blind, placebo-controlled, randomized design. The measures (CAPS-5, SDS, BDI-II) were done by independent researchers. On average, participants had lived with PTSD for 14 years.

“The mean change in CAPS-5 scores from baseline to 18 weeks after baseline in the completers (per protocol set) was −24.4 (s.d. 11.6) (n=42) in the MDMA-assisted therapy group compared with −13.9 (s.d. 11.5) (n=37) in the placebo with therapy group.”

The effect size was large (d = 0.91), which means that there is a large difference between both groups (as you can see from the numbers above). Compared to doing nothing (baseline) the effect size is an even more impressive d = 2.1 (and d = 1.2 for the placebo plus therapy group).

Functional impairment (SDS) decreased, and scores on a measure of depression (BDI-II) also decreased by twice as much in the MDMA-group.

Participants with comorbidities (e.g. dissociative subtype, alcohol use disorder (AUD), addiction (SUD), severe childhood trauma) were just as receptive as those without comorbidities.

At the primary study endpoint (18 weeks after baseline), 28 of 42 (67%) of the participants in the MDMA group no longer met the diagnostic criteria for PTSD, compared with 12 of 37 (32%) of those in the placebo group after three sessions. Additionally, 14 of 42 participants in the MDMA group (33%) and 2 of 37 participants in the placebo group (5%) met the criteria for remission after three sessions.”

These results are great and show that, in combination with therapy, MDMA is more effective than current treatments. A head-to-head comparison still needs to be done.

What is also promising is the safety profile. There were no increases in suicidality (SI). “Although the number of participants who reported suicidal ideation varied throughout the visits, prevalence never exceeded baseline and was not exacerbated in the MDMA group.”


The authors are quick to point out the much smaller effect sizes of SSRIs, and seem to invite a direct comparison.

Earlier research points towards SSRIs themselves being a hinder to the effectiveness of MDMA-assisted therapy. An earlier study on data from the Phase 2 trial by Feduccia and colleagues (2020) indicated that. In the current study, 66% used SSRIs (and discontinued them before the study started) so it’s difficult to pick that apart in the current study.

Why MDMA may work (so well) for PTSD is also explained: “… data suggest that MDMA may exert its therapeutic effects through a well-conserved mechanism of amygdalar serotonergic function that regulates fear-based behaviors and contributes to the maintenance of PTSD. Perhaps by reopening an oxytocin-dependent critical period of neuroplasticity that typically closes after adolescence15, MDMA may facilitate the processing and release of particularly intractable, potentially developmental, fear-related memories.”

Or, as put in the next paragraphs, MDMA may help with recalling negative memories with more self-compassion.

One group that may be helped by MDMA-assisted therapy are veterans (16 participated in this study). The cost to the US government (not even considering the psychological and personal costs) of PTSD (and other service-related disabilities) is $73 billion.

Another great aspect of this study is the inclusion and analysis of data of those with comorbidities. It’s common for studies to study patients with only one indication (e.g. only depression but not suicidal ideation). By including those with substance use disorders, childhood traumas, and more, the external validity (how generalizable the results are) is greatly increased.

What can be better?

The current study only looked at data up to 5 weeks after the final integration session. Future studies (with these patients) will be able to show longer-term follow-up results. Based on the Phase 2 study (Jerome et al., 2020), we can expect scores to remain the same or improve.

Blinding is always difficult in these studies (the therapist will most likely guess correctly who has gotten MDMA or a placebo), still 10% of participants (vs 50% guess) incorrectly guessed which condition they were in.

This study was conducted with a small group of participants who might have been very enthusiastic about the effects of MDMA (i.e. expectancy effects). Larger trials with a more diverse group of patients should be able to help with the generalizability of these results. But note, this should not prevent MDMA-assisted therapy to be approved now.

Study details

Compounds studied

Topics studied

Study characteristics
Original Placebo-Controlled Double-Blind Randomized

90 Humans


Authors associated with this publication with profiles on Blossom

Michael Mithoefer
Michael Mithoefer is a psychiatrist and a Clinical Investigator and acting Medical Director of MAPS Public Benefit Corporation.

Rick Doblin
Rick Doblin Ph.D. is the founder of MAPS. His persistent work since 1986 has been one of the main drivers behind why psychedelics (including MDMA) are now coming back to therapy.


Institutes associated with this publication

MAPS stands for Multidisciplinary Association for Psychedelic Studies, it's the front runner in making psychedelics a legal way to use (and improve) in therapy.

Compound Details

The psychedelics given at which dose and how many times

MDMA 80 - 120
mg | 3x

Linked Research Papers

Notable research papers that build on or are influenced by this paper

Self-experience in MDMA assisted therapy of PTSD
This pre-print re-analysis of an RCT of MDMA-assisted therapy for PTSD finds that study participants (n=90) had significant improvements in the measures of self-experience (e.g. alexithymia - the inability to identify & describe emotions experienced by oneself). The change in scores of self-experience correlate with recovery from PTSD.

The Costs and Health Benefits of Expanded Access to MDMA-assisted Therapy for Chronic and Severe PTSD in the USA: A Modeling Study
This study (2022) uses a decision-analytic model to assess the cost and health benefits of expanded access to MDMA-assisted therapy (MDMA-AT) in the phase III clinical trials from MAPS. Expanding access to MDMA-AT to 25-75% of eligible patients was projected to avert 43,618-106,932 deaths and gain 3.3-8.2 million quality-adjusted life-years (QALYs).

Updated cost-effectiveness of MDMA-assisted therapy for the treatment of posttraumatic stress disorder in the United States: Findings from a phase 3 trial
This study (2022) builds on previous research assessing the cost-effectiveness of MDMA-assisted therapy (MDMA-AT) for the treatment of PTSD by assessing the data from a recent phase III trial. MDMA-AT as conducted in the phase III trial costs $11,537 per patient. Compared to the standard of care for 1,000 patients, MDMA-AT generates discounted net health care savings of $132.9 million over 30 years. Ultimately, MDMA-AT for severe or chronic PTSD is cost-saving while delivering substantial clinical benefit.

Linked Clinical Trial

A Multi-Site Phase 3 Study of MDMA-Assisted Psychotherapy for PTSD (MAPP1)
Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder that can develop after a traumatic life experience that severely reduces the quality of life. This multi-site, double-blind, placebo-controlled, randomized Phase 3 study assessed the efficacy and safety of MDMA-assisted psychotherapy compared to psychotherapy with placebo in participants diagnosed with at least moderate PTSD.

PDF of MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study