Lysia Demetriou

Perceptive Inc. (formerly Invicro LLC), Hammersmith Hospital, London (Wall, Demetriou, Ertl); Department of Metabolism, Digestion, and Reproduction (Wall, Ertl) and Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Faculty of Medicine (Wall, Ertl, Giribaldi, Roseman, Erritzoe, Nutt, Carhart-Harris), Imperial College London; Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK (Demetriou); Department of Neurology, University of California, San Francisco (Carhart-Harris).

3 papers in the library · 234 citations · publishing 2020-2025

Papers

Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression

Journal of Psychopharmacology January 16, 2020 Lea J. Mertens, Matthew B. Wall, Leor Roseman et al. 211 citations

After a single 25 mg dose of psilocybin, patients with treatment-resistant depression showed decreased functional connectivity between the ventromedial prefrontal cortex and the right amygdala while viewing faces, particularly fearful and neutral ones. This decrease was linked to lower rumination levels one week later. Increased connectivity between these regions and occipital-parietal cortices also emerged. The findings suggest psilocybin therapy may revive emotional responsiveness at both neural and psychological levels, offering a potential treatment mechanism. Placebo-controlled studies are needed to confirm these results.

DOI: 10.1177/0269881119895520 Psilocybin Treatment-resistant depression Major depressive disorder Amygdala +8

Reduced Brain Responsiveness to Emotional Stimuli With Escitalopram But Not Psilocybin Therapy for Depression

American Journal of Psychiatry May 7, 2025 Matthew B Wall, Lysia Demetriou, Bruna Giribaldi et al. 16 citations

Psilocybin therapy greatly improved depressive symptoms but had only a small effect on how the brain responds to emotional stimuli. This contrasts with SSRIs, which often reduce emotional responsiveness alongside their antidepressant action. The findings suggest that psychedelic therapy may work through different neural mechanisms than conventional antidepressants.

DOI: 10.1176/appi.ajp.20230751 Psilocybin Cognitive neuroscience Depressive disorders Psychopharmacology +7

Reduced brain responsiveness to emotional stimuli with escitalopram but not psilocybin therapy for depression

medRxiv June 3, 2023 Matthew B. Wall, Lysia Demetriou, Bruna Giribaldi et al. 7 citations preprint

Psilocybin therapy for major depressive disorder may work through a different brain mechanism than the SSRI escitalopram. In a trial comparing two groups—one receiving two 25 mg psilocybin doses plus daily placebo, the other receiving daily escitalopram plus two inactive 1 mg psilocybin doses—brain responses to emotional faces were measured with fMRI before and after six weeks of treatment. The escitalopram group showed significantly reduced brain activity in response to fear, happy, and neutral faces, including a specific reduction in amygdala response to fear faces. The psilocybin group showed no such reduction and even a slight increase in brain responsiveness, despite large improvements in depressive symptoms. Reduced emotional responsiveness may be a biomarker of SSRIs' antidepressant action not shared by psilocybin therapy.

DOI: 10.1101/2023.05.29.23290667 Full text Psilocybin Major depressive disorder Escitalopram Psychology +4