People who received a full dose of MDMA during therapy improved more than those given a very low comparison dose.
A 2018 trial tested MDMA-assisted therapy in veterans, firefighters, and police officers whose PTSD had lasted at least six months and hadn't improved with other treatments.
Twenty-six veterans, firefighters, and police officers with long-standing PTSD received MDMA during two 8-hour therapy sessions. Those given an active dose improved substantially more than a low-dose comparison group, and one year after treatment their PTSD scores had fallen from an average of 87 to 39 — a large, durable reduction. The findings were preliminary, drawn from a small early trial, but they were among the results that carried MDMA-assisted therapy into large-scale testing.
This randomized, double-blind, dose-response Phase 2 trial (n=26) compared full-dose MDMA (75 mg and 125 mg) against a low active-control dose (30 mg), each paired with manualized psychotherapy across two 8-hour sessions. At the primary endpoint the active-dose groups showed significantly greater reductions in clinician-rated PTSD severity than the control group. After all participants crossed over to full-dose treatment, mean symptom scores fell from 87.1 at baseline to 38.8 at the 12-month follow-up.
The effect was large but the evidence is preliminary. The sample is small (n=26); the comparator was a low dose of the same drug rather than an inert placebo; and because MDMA produces salient subjective effects, functional unblinding is likely — participants could often infer their assignment, which can inflate apparent response. The trial was sponsored by an advocacy organization (MAPS), and the sample is mixed (veterans, firefighters, and police), not veteran-specific. The authors frame it as a signal warranting larger confirmatory trials, not as established efficacy.
A qualitative analysis of this same cohort reported durable personal benefits beyond symptom scores (Barone et al., 2019). This was one of several Phase 2 trials that led to the multi-site Phase 3 program, the first of which was positive in a broader PTSD population (Mitchell et al., 2021). Regulatory endorsement did not follow automatically: in August 2024 the FDA declined the MDMA-assisted-therapy application and requested an additional Phase 3 trial — so as of 2026, MDMA remains investigational and Schedule I.
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