Several authors have noted that there are no reported cases of people with schizophrenia who were born blind or who developed blindness shortly after birth, suggesting that congenital or early (C/E) blindness may serve as a protective factor against schizophrenia. By what mechanisms might this effect operate? Here, we hypothesize that C/E blindness offers protection by strengthening cognitive functions whose impairment characterizes schizophrenia, and by constraining cognitive processes that exhibit excessive flexibility in schizophrenia. After briefly summarizing evidence that schizophrenia is fundamentally a cognitive disorder, we review areas of perceptual and cognitive function that are both impaired in the illness and augmented in C/E blindness, as compared to healthy sighted individuals. We next discuss: (1) the role of neuroplasticity in driving these cognitive changes in C/E blindness; (2) evidence that C/E blindness does not confer protective effects against other mental disorders; and (3) evidence that other forms of C/E sensory loss (e.g., deafness) do not reduce the risk of schizophrenia. We conclude by discussing implications of these data for designing cognitive training interventions to reduce schizophrenia-related cognitive impairment, and perhaps to reduce the likelihood of the development of the disorder itself.
Keywords: schizophrenia, blindness, perception, cognition, vision, vision disorders, plasticity
Citation: Silverstein SM, Wang Y and Keane BP (2013) Cognitive and neuroplasticity mechanisms by which congenital or early blindness may confer a protective effect against schizophrenia. Front. Psychology 3:624. doi: 10.3389/fpsyg.2012.00624
Received: 03 November 2012; Accepted: 31 December 2012;
Published online: 21 January 2013.
Edited by:Michael Green, University of California Los Angeles, USA
Reviewed by:Yue Chen, McLean Hospital, USA
Copyright: © 2013 Silverstein, Wang and Keane. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Steven M. Silverstein, University Behavioral HealthCare, University of Medicine and Dentistry of New Jersey, 151 Centennial Avenue, Piscataway, NJ 08854, USA. e-mail: firstname.lastname@example.org