Visual Perception Disturbances in Schizophrenia: A Unified Model.

Abstract

The purpose of this chapter is to demonstrate that the study of visual processing abnormalities in schizophrenia offers a unifying perspective on the etiology, development, pathophysiology, and course of the disorder. This chapter contains six sections. In the first, I provide a brief overview of the importance and promise of studying vision in schizophrenia. In the second, I provide examples of altered visual experience, in multiple aspects of vision, as reported by patients. The third reviews research and controversies related to the most prominent schizophrenia-related visual task deficits, including their psychophysiological and neurobiological aspects. In the fourth, I introduce the construct of contextual modulation and discuss how excesses and reductions in components of this function, in addition to changes in overall level of stimulus sensitivity, can account for many of the visual task deficits associated with schizophrenia. Informed by all of this evidence, I then briefly return to the issue of what the world looks and feels like for people with schizophrenia, and how this may change across illness phases. The paper concludes with a section on future directions for research in the area of vision and schizophrenia.