This review article (2020) highlights the commonalities (reduced integration & stability of functional networks, strong metaphysical meaning) and differences (overactivation of associative networks vs primary sensory cortices, visual vs auditory hallucinations, ‘normal’ insight vs poor reality monitoring) of hallucinations under schizophrenia spectrum disorders (SCZ) and psychedelics.
Abstract
“The recent renaissance of psychedelic science has reignited interest in the similarity of drug-induced experiences to those more commonly observed in psychiatric contexts such as the schizophrenia-spectrum. This report from a multidisciplinary working group of the International Consortium on Hallucinations Research (ICHR) addresses this issue, putting special emphasis on hallucinatory experiences. We review evidence collected at different scales of understanding, from pharmacology to brain-imaging, phenomenology and anthropology, highlighting similarities and differences between hallucinations under psychedelics and in the schizophrenia-spectrum disorders. Finally, we attempt to integrate these findings using computational approaches and conclude with recommendations for future research.”
Authors: Pantelis Leptourgos, Martin Fortier-Davy, Robin L. Carhart-Harris, Philip R. Corlett, David Dupuis, Adam L. Halberstadt, Michael Kometer, Eva Kozakova, Frank LarØi, Tehseen N. Noorani, Katrin H. Preller, Flavie Waters, Yuliya Zaytseva & Renaud Jardri
Summary of Hallucinations Under Psychedelics and in the Schizophrenia Spectrum
Hallucinations are common in psychiatric and neurological disorders, and they can be engendered by psychotomimetic drugs, including serotonergic agonists (ie, psychedelics). The recent revival of psychedelic science has generated new data and ideas, sparking great interest in the relevance of those compounds to psychosis.
This review compares and contrasts hallucinations under psychedelics with those observed in SCZs, focusing on neural mechanisms, subjective features, and the impact of cultural factors.