MDMA-assisted therapy as a treatment for major depressive disorder: proof of principle study

3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy (MDMA-AT) has shown promising safety and efficacy in phase 3 studies of post-traumatic stress disorder, but has not been investigated for a primary diagnosis of major depressive disorder (MDD).

We aimed to explore the proof of principle and safety as a first study with MDMA-AT for MDD, and to provide preliminary efficacy data.

Twelve participants (7 women, 5 men) with moderate to severe MDD received MDMA in 2 open-label sessions 1 month apart, along with psychotherapy before, during and after the MDMA sessions, between January 2023 and May 2024. The primary outcome measure was mean change in Montgomery-Asberg Depression Rating Scale (MADRS), and the secondary outcome measure was mean change in functional impairment as measured with the Sheehan Disability Scale (SDS), both from baseline to 8 weeks following the second MDMA session. We used descriptive statistics and the two-tailed Wilcoxon signed-rank test to compare baseline and outcome scores. Repeated measures were analysed by a mixed-effects model.

Baseline MADRS was 29.6 (s.d. 4.9). Feasibility was demonstrated with sufficient recruitment and retention. MADRS scores were significantly reduced post treatment compared with baseline (mean difference -19.3, s.e. 2.4, CI -14.8 to -23.8, P < 0.001). SDS scores significantly decreased from baseline (mean difference -11.7, s.e. 2.2, CI -7.5 to -15.9, P = 0.001). There were no adverse events of special interest, and no unexpected or serious adverse events.

The study met the primary objectives of safety and feasibility, and provided indications of efficacy for MDMA-AT for MDD. Further studies with a randomised design are required to confirm these findings.

EudraCT no. 2021-000805-26.