A neuropsychological study of early onset schizophrenia

Characterizing a pattern of cognitive dysfunction in early onset schizophrenic patients may illuminate neurodevelopmental contributions to the illness. A cohort of chronically institutionalized schizophrenic patients with a variable range of age of onset (range 7-29 years) was administered a comprehensive battery of neuropsychological tests that included the Luria-Nebraska Neuropsychological Test Battery. After statistical control of age, parental socioeconomic class (SES) effects, and thorazine equivalents, age of illness onset was positively correlated with performance on measures of motor ability, perceptual motor and pure motor speed, receptive and expressive speech, and overall cognition function, and inversely related to severity of negative symptoms; that is, earlier age of onset was associated with worse cognitive performance and an increase in negative symptoms. This study demonstrates that an early age of onset in schizophrenic illness is associated with impairment on tasks which involve motor and language abilities, functions linked to the frontal, temporal, and subcortical regions of the brain. This association is not due to the effects of medication, negative symptoms, or duration of illness.