Development of the MDMA-Assisted Psychotherapy Side Effects Tool (M-SET): A Delphi Study

Background: Despite growing interest in the therapeutic potential of 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 a course of MDMA-AP and at follow-up. Method: Informed by a systematic review as well as a review of other relevant measures, 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. Results: Twelve experts consented to participate over two rounds of Delphi panel deliberations (response rate: R1 = 83-92%, R2 = 75%). The Delphi panelists 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. Conclusion: 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.