The Phenomenology and Neurobiology of Visual Distortions and Hallucinations in Schizophrenia: An Update

Abstract

Schizophrenia is characterized by visual distortions in ~60% of cases, and visual hallucinations (VH) in ~25–50% of cases, depending on the sample. These symptoms have received relatively little attention in the literature, perhaps due to the higher rate of auditory vs. visual hallucinations in psychotic disorders, which is the reverse of what is found in other neuropsychiatric conditions. Given the clinical significance of these perceptual disturbances, our aim is to help address this gap by updating and expanding upon prior reviews. Specifically, we: (1) present findings on the nature and frequency of VH and distortions in schizophrenia; (2) review proposed syndromes of VH in neuro-ophthalmology and neuropsychiatry, and discuss the extent to which these characterize VH in schizophrenia; (3) review potential cortical mechanisms of VH in schizophrenia; (4) review retinal changes that could contribute to VH in schizophrenia; (5) discuss relationships between findings from laboratory measures of visual processing and VH in schizophrenia; and (6) integrate findings across biological and psychological levels to propose an updated model of VH mechanisms, including how their content is determined, and how they may reflect vulnerabilities in the maintenance of a sense of self. In particular, we emphasize the potential role of alterations at multiple points in the visual pathway, including the retina, the roles of multiple neurotransmitters, and the role of a combination of disinhibited default mode network activity and enhanced state-related apical/contextual drive in determining the onset and content of VH. In short, our goal is to cast a fresh light on the under-studied symptoms of VH and visual distortions in schizophrenia for the purposes of informing future work on mechanisms and the development of targeted therapeutic interventions.

The impact of visual dysfunctions in recent-onset psychosis and clinical high-risk state for psychosis

“…In schizophrenia, previous research highlights abnormalities of visual information processing along both visual streams including retinal dysfunctions with a predominance of alterations observed related to the dorsal visual stream [ 3 , 9 – 13 , 60 – 62 ]. For instance, basic visual symptoms correlated with rapid visual processing and magnocellular pathway function [ 63 ].…”

Psychosis Associated with Acquired Porencephaly—Cause or Incidental Finding? Case Report and Review of Literature

“…Regarding the clinical picture of our case, besides common delusions, the patient experienced visual hallucinations, which are atypical and less common than auditory hallucinations in people with psychotic disorders such as schizophrenia [ 20 ]. Furthermore, visual hallucinations are often regarded as a marker for a possible organic aetiology such as epilepsy, migraine or Parkinson’s disease [ 21 ].…”

Working Memory and Sensory Memory in Subclinical High Schizotypy: An Avenue for Understanding Schizophrenia?

“…Similarly, accounts for visual deficits in schizophrenia spectrum disorders identify abnormalities in the anatomy of the retina (reviewed in reviewed in (Bernardin et al, 2017;Silverstein et al, 2020), as well as atypical network-level connectivity, both hypo-and hyper-connectivity, including cortical -medial temporal lobe abnormalities (reviewed in: (Silverstein & Lai, 2021). Together, the consistent oculomotor and low-level visual deficits suggest that processing from as early as the retina is abnormal in schizophrenia.…”

“…Approximately ˜60% of individuals with schizophrenia have distortions in visual perception (Phillipson & Harris, 1985) and >33% experience visual hallucinations (Silverstein & Lai, 2021). The range of perceptual deficits is broad and includes worse performance in assessments of contrast sensitivity (Harper et al, 2020), detection of contour (Keane et al, 2014), color (Fernandes et al, 2019), biological motion (Okruszek & Pilecka, 2017) but see (Keane, Peng, et al, 2018), faces (McCleery et al, 2015), and stronger afterimages (Thakkar et al, 2021).…”