A Prospective Study of Childhood Neurocognitive Functioning in Schizophrenic Patients and Their Siblings

This study evaluated childhood cognitive functioning in individuals who later developed schizophrenia and in their unaffected siblings.Through the National Collaborative Perinatal Project, seven subtests of the Wechsler Intelligence Scale for Children were administered at age 7 to 32 individuals who developed schizophrenia in adulthood, 25 of their nonschizophrenic siblings, and 201 demographically similar nonpsychiatric comparison subjects. Mixed model analysis was used to examine between-group differences in standardized scores on the subtests.The probands and unaffected siblings had lower scores for picture arrangement, vocabulary, and coding than the comparison subjects but differed from each other only on the coding subtest.Children who later developed schizophrenia and their siblings showed similar patterns of deficits involving spatial reasoning, verbal knowledge, perceptual-motor speed, and speeded processes of working memory. However, the probands exhibited more severe deficits in perceptual-motor speed and speeded processes of working memory than their unaffected siblings.