The Reporting of Setting in Psychedelic Clinical Trials (ReSPCT) Guidelines: An international Delphi consensus study

Abstract Background Psychedelic substances exhibit complex interactions with the ‘set and setting’ of use, i.e., the internal state of the user and the external environment in which a psychedelic experience takes place. Despite the known importance of these contextual variables, psychedelic research has suffered from methodological weaknesses in reporting extra-pharmacological factors and from a lack of consensus regarding their relative importance.

Methods: The study aimed to generate consensus-based guidelines for the reporting of settings in psychedelic clinical research, according to a diverse international group of psychedelic researchers, clinicians, and past trial participants. We conducted a large international Delphi consensus study composed of four iterative rounds of quasi-anonymous online surveys and facilitated debates.

Findings: Eighty-nine experts from 17 countries initially identified hundreds of potentially important psychedelic setting variables. These 770 responses were synthesized into 49 distinct items that were then rated, debated, and refined in subsequent rounds. The process resulted in 30 extra-pharmacological variables reaching pre-defined consensus thresholds: rated “important” or “very important” for reporting by at least 70% of experts. These items compose the Reporting of Setting in Psychedelic Clinical Trials (ReSPCT) guidelines, categorized into: physical environment, dosing session procedure, therapeutic framework and protocol, and subjective experiences. Emergent study findings reveal significant ambiguities in current conceptualizations of set and setting.

Interpretation: The ReSPCT guidelines and its accompanying explanatory document provide a new standard for the design and documentation of extra-pharmacological variables in psychedelic clinical research. Drug-context interactions warrant further attention to ensure the methodological rigor of psychedelic research.

Funding: Societal Engagement Seed Fund, Imperial College London.