Comparative study of neuropsychological correlates in schizophrenia with onset in childhood, adolescence and adulthood

Childhood onset schizophrenia (COS) patients have marked neuropsychological deficits in areas of attention, working memory and executive functions. Similar deficits have been found in studies on Adolescent onset (AdOS) and Adult onset schizophrenia (AOS). In this study we compared the neuropsychological profile of COS with AdOS and AOS to test the hypothesis that earlier the onset greater is the severity of illness and greater are the neuropsychological deficits. A sample of 15 patients of COS was compared with 20 patients each of AdOS and AOS group. Assessment of neuropsychological profile was done using standard neuropsychological battery for Indian population. Nahor Benson Test and Bender Visual Motor Gestalt Test were used to assess perceptuomotor functioning. COS patients showed significantly greater deficits on scales of IQ, memory and perceptuomotor skills as compared to AdOS that in turn had greater deficits than AOS. The persistence of differences across the three groups inspite of controlling for education and age suggest that these deficits may have been present even before the onset of illness and was not the result of poor academic achievements. These findings also point towards a brain damage in schizophrenia that occurs on a continuum of severity with COS being the most virulent, AOS being the least and AdOS falling in between these two extremes.