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

Jennifer Mitchell, Michael P. Bogenschutz, Alia Lilienstein, Charlotte Harrison, Sarah E. Kleiman, Kelly Parker-Guilbert et al. · 2021 · 968 citationsRead the paper

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.

What the full text shows

Tested in real conditions
  • MDMA-assisted therapy significantly reduced PTSD symptom severity compared to placebo. — -24.4 mean change in CAPS-5 vs -13.9 for placebo (d = 0.91, P < 0.0001) (Severe PTSD patients, 18 weeks after baseline)
  • MDMA-assisted therapy significantly decreased functional impairment. — -3.1 mean change in SDS vs -2.0 for placebo (d = 0.43, P = 0.0116) (Severe PTSD patients, 18 weeks after baseline)
  • A majority of MDMA participants no longer met the diagnostic criteria for PTSD. — 67% vs 32% in placebo group (18 weeks after baseline)
  • MDMA-assisted therapy led to higher remission rates. — 33% vs 5% in placebo group (18 weeks after baseline)
  • MDMA significantly reduced depressive symptoms. — -19.7 mean change in BDI-II vs -10.8 for placebo (d = 0.67, P = 0.0026) (Exploratory endpoint analysis)
  • MDMA was effective for the dissociative subtype of PTSD. — -30.8 mean change in CAPS-5 vs -12.8 for placebo (Participants with dissociative subtype of PTSD)
Setup
90 participants with severe PTSD (CAPS-5 score ≥ 35) across 15 sites in the US, Canada, and Israel.
How
A randomized, double-blind, placebo-controlled phase 3 trial where participants received either MDMA (80–180 mg) or placebo across three experimental sessions, combined with three preparatory and nine integrative therapy sessions. Efficacy was measured using the CAPS-5 and SDS scales by a blinded, independent rater pool.
Limitations
Small sample size (n=90) compared to typical phase 3 trials. · Use of an inactive placebo may have compromised blinding. · Potential influence of previous SSRI use on treatment resistance, though no obvious effect was seen in this trial.

Summarized by Gemma 4 from the open-access full text · 2 Oct 2026. Read it