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 K. 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 DOI: 10.1136/bmjopen-2025-105630 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Tool development with modified Delphi process Peer reviewed |
|---|---|
| Sample size | 12 |
| Population | Experts in MDMA-assisted psychotherapy and neuropsychopharmacology of MDMA |
| Topics | MDMA Psychedelic-assisted therapy |
| Keywords | Adult psychiatry Adverse events |
| Key points | A structured 165-item tool (M-SET) was developed through expert consensus to systematically assess side effects of 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.