Knowledge gaps in psychedelic medicalisation: Clinical studies and regulatory aspects

Psychedelic drugs including psilocybin and LSD are undergoing clinical trials for a range of psychiatric and neurological conditions, and have particularly shown substantial promise in phase 2 studies of depression. In this article we outline key knowledge gaps that may be imperative for a successful implementation of psychedelic drugs as medicines as identified by members of the European College of Neuropsychopharmacology at the New Frontiers Meeting in Nice (2023). Key themes include pharmacokinetic and pharmacodynamic characterisation, comparisons between psychedelics, the relation between the duration of subjective effects and therapeutic outcomes, polypharmacology, and the impact of psychological support. We conclude with a perspective from the European Medicines Agency and Heath Technology Assessors on the most pressing requirements for medical implementation in Europe.