Skip to content

Robert Leech

Wellcome Centre for Human Neuroimaging, King's College London

30 papers in the library · 8,926 citations · publishing 2011-2026

Papers

How to set up a psychedelic study: Unique considerations for research involving human participants.

Neuroscience and biobehavioral reviews July 1, 2026 Marcus J Glennon, Catherine I V Bird, Prateek Yadav et al. 2 citations

Setting up a psychedelic research study involves a long, arduous, and Kafkaesque process with many unstandardised challenges. These complexities challenge existing assumptions about psychiatric prescribing, the placebo effect, and definitions of selfhood. This review brings together major UK psychedelic research teams to formalise these unique considerations, addressing sociocultural, political, legal, pharmacological, safety, study design, and experiential facets. It identifies continuing areas of debate and provides a practical, experience-based guide with recommendations for policymakers and future researchers intending to set up a psychedelic study or clinical trial.

Neural correlates of the LSD experience revealed by multimodal neuroimaging

UNC Libraries April 22, 2020 Peter J. Hellyer, Luke T. Williams, Ben Sessa et al. 1 citation

Lysergic acid diethylamide (LSD) in microgram doses produces profound, sometimes life-changing experiences and is a uniquely powerful psychoactive substance. In the first modern neuroimaging study of LSD, marked changes in brain blood flow, electrical activity, and network communication patterns were observed. These changes correlated strongly with the drug's hallucinatory and consciousness-altering properties. The findings have implications for understanding the neurobiology of consciousness and for potential applications of LSD in psychological research.

How to set up a psychedelic study: Unique considerations for research involving human participants

arXiv Preprint Archive March 28, 2025 Marcus J. Glennon, Catherine I. V. Bird, Prateek Yadav et al.

Setting up a psychedelic study is a long and complex process that presents unique challenges not yet standardized. This review brings together major UK research teams to formalize these considerations, identify ongoing debates, and provide a practical guide for researchers and policymakers. It addresses challenges to existing assumptions about psychiatric prescribing, the placebo effect, and definitions of selfhood. The paper can be read end-to-end or used as a manual with sections for specific needs.

Fine-tuning neural excitation/inhibition for tailored ketamine use in treatment-resistant depression

arXiv Preprint Archive February 4, 2021 Erik D. Fagerholm, Robert Leech, Steven Williams et al.

Ketamine rapidly reduces depressive symptoms in treatment-resistant major depressive disorder. Using brain imaging and dynamic causal modeling, researchers analyzed neural excitation/inhibition interactions in the primary somatosensory cortex of 18 unmedicated patients and 18 healthy controls during a somatosensory task. Patients were scanned at baseline, 6-9 hours after ketamine infusion, and 6-9 hours after placebo. A shift in neural dynamics toward a stable region of the Poincaré diagram—requiring increased excitatory and inhibitory coupling—predicted symptom improvement specifically after ketamine, not placebo. This drug-specific neural shift may serve as a biomarker for treatment response.

Enhanced repertoire of brain dynamical states during the psychedelic experience

arXiv Preprint Archive May 26, 2014 Enzo Tagliazucchi, Robin Carhart-Harris, Robert Leech et al.

Psilocybin, the active compound in magic mushrooms, dramatically expands the brain's repertoire of connectivity states, revealing how consciousness can be altered. Using advanced brain imaging, researchers tracked neural activity before and after psilocybin administration. Results showed increased signal variability in memory and emotion-processing regions, while higher brain networks displayed enhanced flexibility in their communication patterns.