Atypical Use of Visuospatial Context in Psychotic Psychopathology: A Meta-analysis.

Abstract

Background and hypothesis: Visual perception in people with psychotic disorders is thought to be minimally influenced by surrounding visual elements (ie, visuospatial context). Visuospatial context paradigms have the unique potential to clarify the neural bases of psychotic disorders because the neural mechanisms are well studied in both animal and human models. However, the published literature on the subject is conflicting and heterogeneous. A systematic consolidation and evaluation of the published evidence is needed.

Study design: We conducted a meta-analysis of 54 articles spanning over 50 years of research. Articles included behavioral, functional magnetic resonance imaging, and electroencephalogram reports of size, contrast, contour, lightness, orientation, and motion perception in schizophrenia (SCZ), bipolar disorder, and subclinical populations.

Study results: When pooling across all task types, we found weak evidence of reduced use of visuospatial context in SCZ (Hedges' g = 0.20) and bipolar disorder (g = 0.25). The strongest evidence was observed for altered contrast perception in SCZ (g = 0.73). With respect to subclinical populations, we observed immense heterogeneity in populations of interest and study designs.

Conclusions: We observed surprisingly weak evidence that psychotic disorders are associated with generally reduced use of visuospatial context. Instead, we observed the strongest evidence for a specific alteration in contrast perception. We propose altered feedback to the primary visual cortex as a potential neural mechanism underlying this effect. Moderating factors such as stage and phase of illness may explain some of the heterogeneity we observed in effect sizes; further research is needed to clarify how disease state relates to altered use of visuospatial context.