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Steven C. R. Williams

6 papers in the library · 162 citations · publishing 2012-2021

Papers

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Eye movements in patients in early psychosis with and without a history of cannabis use

Schizophrenia May 12, 2021 Musa Basseer Sami, Luciano Annibale, Aisling O’neill et al. 5 citations

Abstract It is unclear whether early psychosis in the context of cannabis use is different from psychosis without cannabis. We investigated this issue by examining whether abnormalities in oculomotor control differ between patients with psychosis with and without a history of cannabis use. We studied four groups: patients in the early phase of psychosis with a history of cannabis use (EPC; n =...

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 C. R. Williams et al. preprint

The glutamatergic modulator ketamine has been shown to rapidly reduce depressive symptoms in patients with treatment-resistant major depressive disorder (TRD). Although its mechanisms of action are not fully understood, changes in cortical excitation/inhibition (E/I) following ketamine administration are well documented in animal models and could represent a potential biomarker of treatment...

Full text (opens in new tab) Q-bio.qm Depression treatment Ketamine therapy Brain imaging

Differential sensitivity to the acute psychotomimetic effects of delta-9-tetrahydrocannabinol associated with its differential acute effects on glial function and cortisol

Psychological Medicine October 27, 2020 Marco Colizzi, Nathalie Weltens, David J Lythgoe et al. 8 citations

Abstract Background Cannabis use has been associated with psychosis through exposure to delta-9-tetrahydrocannabinol (Δ9-THC), its key psychoactive ingredient. Although preclinical and human evidence suggests that Δ9-THC acutely modulates glial function and hypothalamic-pituitary-adrenal (HPA) axis activity, whether differential sensitivity to the acute psychotomimetic effects of Δ9-THC is...

Cannabis Use Linked to Altered Functional Connectivity of the Visual Attentional Connectivity in Patients With Psychosis and Controls

Schizophrenia Bulletin Open 2020 Musa Sami, Robert A. McCutcheon, Ulrich Ettinger et al.

Both chronic cannabis use and psychotic disorders are associated with abnormalities in visual attentional processing. Using functional magnetic resonance imaging (fMRI), we sought to determine whether there would be a difference in functional connectivity in patients and controls with and without a history of cannabis use in the visual and dorsal attention networks. Resting-state fMRI data were...

Modulation of acute effects of delta-9-tetrahydrocannabinol on psychotomimetic effects, cognition and brain function by previous cannabis exposure.

European Neuropsychopharmacology July 1, 2018 Marco Colizzi, P. McGuire, Vincent Giampietro et al.

Cannabis use has been associated with psychosis and cognitive dysfunction. Some evidence suggests that the acute behavioral and neurocognitive effects of the main active ingredient in cannabis, (-)-trans-Δ9-tetrahydrocannabinol (∆9-THC), might be modulated by previous cannabis exposure. However, this has not been investigated either using a control group of non-users, or following abstinence in...

Modulating the Default Mode Network Using Hypnosis

International Journal of Clinical and Experimental Hypnosis March 24, 2012 Quinton Deeley, David A Oakley, Brian Toone et al. 149 citations

Debate regarding the neural basis of the hypnotic state continues, but a recent hypothesis suggests that it may produce alterations in the default mode network (DMN). DMN describes a network of brain regions more active during low-demand compared to high-demand task conditions and has been linked to processes such as task-independent thinking, episodic memory, semantic processing, and...