Visual form perception: a comparison of individuals at high risk for psychosis, recent onset schizophrenia and chronic schizophrenia.

Schizophrenia has been associated with deficits in visual perception and processing, but there is little information about their temporal development and stability. We assessed visual form perception using the Rorschach Comprehensive System (RCS) in 23 individuals at clinical high risk for psychosis, 15 individuals with recent onset schizophrenia (< or =2 years since onset), and 34 with chronic schizophrenia (> or =3 years since onset). All three groups demonstrated reduced conventional form perception (X+%), as compared with published norms, but did not differ significantly from one another. In contrast, the high-risk group had significantly better performance on an index of clarity of conceptual thinking (WSUM6) compared to the chronic schizophrenia patients, with the recent onset group scoring intermediate to the high-risk and chronic schizophrenia groups. The results suggest that individuals at clinical high risk for psychosis display substantial deficits in visual form perception prior to the onset of psychosis and that these deficits are comparable in severity to those observed in individuals with schizophrenia. Therefore, visual form perception deficits may constitute a trait-like risk factor for psychosis in high-risk individuals and may potentially serve as an endophenotype of risk for development of psychosis. Clarity of conceptual thinking was relatively preserved among high-risk patients, consistent with a relationship to disease expression, not risk. These deficits are discussed in the context of the putative neurobiological underpinnings of visual deficits and the developmental pathophysiology of psychosis in schizophrenia.