Neuropsychological Deficits in Adolescent-Onset Schizophrenia Compared With Attention Deficit Hyperactivity Disorder

OBJECTIVE: Impaired neuropsychological performance involving abstraction-flexibility, memory, motor function, and attention has frequently been reported in schizophrenia as well as in attention deficit hyperactivity disorder (ADHD). This study represents an attempt to compare groups of adolescents with schizophrenia and ADHD on a comprehensive neuropsychological test battery. Such a comparison affords the opportunity to ascertain differences in the degree, profile, and specificity of impairments. METHOD: The performance of 19 adolescents with schizophrenia, 20 adolescents with ADHD, and 30 normal adolescents on a broad battery of cognitive tests was compared. RESULTS: The schizophrenic group showed the most pronounced deficits on tests of abstraction, visual memory, and motor function in comparison with the subjects with ADHD, while the ADHD subjects had the most pronounced deficits on measures of attention, verbal memory, and learning. CONCLUSIONS: The subjects with schizophrenia appeared to have a more general pattern of brain dysfunction, whereas the impairment of the ADHD subjects seemed to be relatively specific to tests associated with frontal lobe function.