title: Visual hallucinations in the psychosis spectrum and comparative information from neurodegenerative disorders and eye disease.
abstract: Much of the research on visual hallucinations (VHs) has been conducted in the context of eye disease and neurodegenerative conditions, but little is known about these phenomena in psychiatric and nonclinical populations. The purpose of this article is to bring together current knowledge regarding VHs in the psychosis phenotype and contrast this data with the literature drawn from neurodegenerative disorders and eye disease. The evidence challenges the traditional views that VHs are atypical or uncommon in psychosis. The weighted mean for VHs is 27% in schizophrenia, 15% in affective psychosis, and 7.3% in the general community. VHs are linked to a more severe psychopathological profile and less favorable outcome in psychosis and neurodegenerative conditions. VHs typically co-occur with auditory hallucinations, suggesting a common etiological cause. VHs in psychosis are also remarkably complex, negative in content, and are interpreted to have personal relevance. The cognitive mechanisms of VHs in psychosis have rarely been investigated, but existing studies point to source-monitoring deficits and distortions in top-down mechanisms, although evidence for visual processing deficits, which feature strongly in the organic literature, is lacking. Brain imaging studies point to the activation of visual cortex during hallucinations on a background of structural and connectivity changes within wider brain networks. The relationship between VHs in psychosis, eye disease, and neurodegeneration remains unclear, although the pattern of similarities and differences described in this review suggests that comparative studies may have potentially important clinical and theoretical implications.
authors.affiliation: Clinical Research Centre, Graylands Hospital, North Metropolitan Health Service Mental Health, Perth, Western Australia, Australia; Centre for Clinical Research in Neuropsychiatry, School of Psychiatry and Clinical Neurosciences, the University of Western Australia, Perth, Western Australia, Australia; Flavie.waters@health.wa.gov.au.
authors.forename: Flavie
authors.initials: F
authors.lastname: Waters
authors.affiliation: Northumberland, Tyne and Wear NHS Foundation Trust, Bensham Hospital, Gateshead and Newcastle University, Newcastle Upon Tyne, UK;
authors.forename: Daniel
authors.initials: D
authors.lastname: Collerton
authors.affiliation: Institute of Psychiatry, King's College London, London, UK;
authors.forename: Dominic H
authors.initials: DH
authors.lastname: Ffytche
authors.affiliation: Laboratoire de Neurosciences Fonctionnelles & Pathologies, Université Droit & Santé (UDSL), Univ Lille Nord de France and Centre Hospitalier Universitaire (CHU Lille), Hôpital Fontan, Lille, France;
authors.forename: Renaud
authors.initials: R
authors.lastname: Jardri
authors.affiliation: Laboratoire de Neurosciences Fonctionnelles & Pathologies, Université Droit & Santé (UDSL), Univ Lille Nord de France and Centre Hospitalier Universitaire (CHU Lille), Hôpital Fontan, Lille, France;
authors.forename: Delphine
authors.initials: D
authors.lastname: Pins
authors.affiliation: School of Psychology, Newcastle University, Newcastle Upon Tyne, UK; South of Tyne Early Intervention in Psychosis Service, Northumberland, Tyne and Wear NHS Foundation Trust, Newcastle Upon Tyne, UK;
authors.forename: Robert
authors.initials: R
authors.lastname: Dudley
authors.affiliation: Parnassia Psychiatric Institute, The Hague, The Netherlands; Department of Psychiatry, University of Groningen, Groningen, The Netherlands;
authors.forename: Jan Dirk
authors.initials: JD
authors.lastname: Blom
authors.affiliation: University Hospital of Old Age Psychiatry, University of Bern, Bern, Switzerland;
authors.forename: Urs Peter
authors.initials: UP
authors.lastname: Mosimann
authors.affiliation: Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK;
authors.forename: Frank
authors.initials: F
authors.lastname: Eperjesi
authors.affiliation: Department of Psychiatry, Sir Charles Gairdner Hospital, North Metropolitan Health Service Mental Health - Older Adult Program, Perth, Western Australia, Australia;
authors.forename: Stephen
authors.initials: S
authors.lastname: Ford
authors.affiliation: Department of Psychology: Cognition and Behaviour, University of Liège, Liège, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Larøi
mesh_terms: D000341:Affective Disorders, Psychotic / Q000503:physiopathology / Q000523:psychology*; D001921:Brain / Q000503:physiopathology; D005128:Eye Diseases / Q000503:physiopathology; D006212:Hallucinations / Q000503:physiopathology / Q000523:psychology* / Q000628:therapy; D006801:Humans; D019636:Neurodegenerative Diseases / Q000503:physiopathology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D014793:Visual Cortex / Q000503:physiopathology*
keywords: cognition; imaging; psychosis; schizophrenia; visual hallucinations