Development of the MDMA-Assisted Psychotherapy Side Effects Tool (M-SET): a Delphi study.
Julia Colcott, Alexandre A Guerin, Olivia Carter, Matthew J Baggott, Anya Bershad, Alicia Danforth, Harriet de Wit, Allison A Feduccia, Matthew G Kirkpatrick, Matthias E Liechti, Peter Oehen, Yasmin Schmid, Gillinder Bedi
BMJ open May 11, 2026 Peer reviewed DOI: 10.1136/bmjopen-2025-105630 via PubMed
Summary
An MDMA-Assisted Psychotherapy Side Effects Tool (M-SET) was developed to systematically assess side effects during MDMA-assisted psychotherapy. The tool was created through a modified Delphi process involving 12 experts, resulting in a final version with 165 items across four questionnaires for various assessment points. This structured tool aims to enhance safety and support evidence on the tolerability of MDMA-assisted therapy.
Study at a glance
| Design | Delphi study |
|---|---|
| Sample size | 12 |
| Population | experts in MDMA-assisted psychotherapy and neuropsychopharmacology |
| Key finding | The M-SET was successfully developed as the first structured tool to evaluate side effects specifically associated with MDMA-assisted psychotherapy. |
Abstract
Despite growing interest in the therapeutic potential of 3,4-methylenedioxymethamphetamine (MDMA), no targeted measure to systematically assess side effects of MDMA-assisted psychotherapy (MDMA-AP) exists. Our aim was to develop an MDMA-Assisted Psychotherapy Side Effects Tool (M-SET) to capture side effects over the course of MDMA-AP. Informed by a systematic review and a review of other relevant questionnaires, we drafted a list of potential side effects. Face and content validation were obtained via a modified two-round online Delphi process involving experts in MDMA-AP and the neuropsychopharmacology of MDMA. Twelve experts consented to participate over two rounds of Delphi panel deliberations (response rate: Round 1 = 83-92%, Round 2 = 75%). The Delphi panellists were asked to keep, discard, modify or suggest additional items. The final version of the M-SET consists of 165 items across four questionnaires that collect information at screening, baseline, the day of medication sessions and longer term follow-up. The use of a modified Delphi technique proved a successful method to generate content for the first structured tool designed to evaluate side effects specifically associated with MDMA-AP. The M-SET is recommended for use in both research and clinical settings. Its implementation has the potential to improve the safety of delivering MDMA-AP as well as support the development of a more systematic and robust evidence base on its safety and tolerability.