A lexicon for psychedelic research and treatment

Authors

David J. Nutt, David Erritzoe, Anne Schlag, David Luke, Deborah C. Mash, Hiroyuki Uchida, Jacob S. Aday, James Rucker, Liliana Galindo, Mark Sweeney, Matthew X. Lowe, Oliver Davis, Plinio Ferreira, Rayyan Zafar, Robin Carhart-Harris, Tadeusz Hawrot and Jo Neill

Published

Sept 22, 2025

Led by Prof David Nutt, the Drug Science Medical Psychedelics Working Group today published a key paper delineating a standardised terminology for clinical development and regulatory classification for psychedelic medicines.

Psychedelics are undergoing a clinical research renaissance, with compounds such as psilocybin advancing to Phase 3 trials for treatment-resistant depression and receiving fast-track or breakthrough designations from regulatory agencies. Despite this progress, the field lacks standardised terminology to guide clinical development, dosing, safety monitoring, and regulatory classification. This paper presents a comprehensive framework for psychedelic nomenclature based on pharmacology, subjective effects, dosing, and therapeutic use. A pharmacological classification system is described, encompassing serotonergic, glutamatergic, kappaergic, GABAergic, and atypical psychedelics. Dose-dependent categories—microdose, minidose, mididose, and macrodose—are introduced to standardise the description of dosing levels and intended subjective effects.

The authors also standardise vague terms like “short-acting” or “long-acting” with specific pharmacokinetic parameters, including route, onset, and duration of action. Safety considerations are also explored, particularly cardiovascular and psychological effects, and we discuss the need for risk mitigation protocols in higher-risk compounds like ibogaine.

The evolving role of psychotherapy in psychedelic treatment is examined, proposing terminology to distinguish between “psychedelic therapy” and varying levels of psychological support. A three-phase treatment model—preparation, dosing, and integration—is recommended as a minimum standard for safe and effective care. The lack of comparative research on psychotherapy modalities in psychedelic therapy is identified as a critical gap. Ultimately, a standardised lexicon and clinical framework will support clearer communication, improved trial design, and more equitable access as psychedelic therapies move toward widespread clinical use.

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