JAMA Network Open
May 1, 2020
K. Beck, Guy Hindley, F. Borgan et al.
179 citations
Ketamine administration produces transient psychopathological effects in both healthy volunteers and patients with schizophrenia, with the nature and severity of these effects varying according to experimental factors such as dose, route of administration, and participant characteristics. The meta-analysis quantifies these outcomes, showing that ketamine reliably induces psychotic-like symptoms, dissociation, and cognitive impairments in healthy individuals, while its effects in patients with schizophrenia are more complex and may involve both symptom exacerbation and potential therapeutic benefits depending on the context.
European Psychiatry
November 17, 2023
K. Beck, A. Arumuham, S. Brugger et al.
1 citation
In people experiencing a first episode of psychosis, availability of N-methyl-D-aspartate receptors (NMDARs) in the hippocampus is lower than in matched healthy controls. Lower hippocampal NMDAR availability was linked to more severe overall, depressive, and general symptoms, and also to higher levels of the neurotransmitter glutamate in the striatum. No significant differences in NMDAR availability were found in other brain regions examined. These results support the hypothesis that reduced NMDAR function contributes to psychosis and point to the hippocampus as a key brain area involved.
Schizophrenia Bulletin Open
January 1, 2020
M. Sami, R. Mccutcheon, U. Ettinger et al.
Both chronic cannabis use and psychotic disorders are linked to abnormalities in how the brain processes visual attention. Using resting-state fMRI, connectivity was measured in the visual and dorsal attention networks of people with early psychosis who did or did not use cannabis, and healthy controls who did or did not use cannabis. Patients with a history of cannabis use showed increased connectivity in the dorsal attention network (134%) and between the visual and dorsal attention networks (285%) compared to non-using controls. In patients who used cannabis, connectivity in these networks correlated with visual hallucinations and with severity of cannabis dependence. The findings suggest that disrupted connectivity in these networks may play different roles depending on cannabis use.