Early stage vision in schizophrenia and schizotypal personality disorder

Previous studies of visual perception have reported deficits in contrast sensitivity and dot motion discrimination in schizophrenia. We tested whether these deficits also appear in schizotypal personality disorder (SPD). SPD appears to be genetically and symptomatically related to schizophrenia, but without the marked psychosocial impairment associated with psychotic disorders. The present study investigated contrast sensitivity for moving and static gratings, form discrimination and dot motion discrimination in 24 patients with schizophrenia or schizoaffective disorder (SZ), 16 individuals with SPD, and 40 control subjects. SZ, but not SPD subjects, showed impairments on tests of contrast sensitivity for static and moving gratings, form discrimination in noise, and dot motion discrimination. Visual performance did not differ between medicated SZ patients and patients withdrawn from medication. These results confirm early stage visual deficits in schizophrenia regardless of medication status. SPD subjects, in contrast, show intact early stage visual processing despite the presence of marked schizotypal symptoms. (c) 2006 Elsevier B.V. All rights reserved.