Memory and frontal lobe dysfunction in schizophrenia and schizoaffective disorder.

Verbal memory and performance on a number of tests known to be sensitive to lesions that disrupt frontal lobe functioning were studied in patients with schizophrenia or schizoaffective illness. Both patient groups were severely and equally impaired on verbal and design fluency and on the Wisconsin Card Sorting Test, measures that are sensitive to dysfunction of frontal-striatal circuitry. Both patient groups exhibited impaired recall but nearly normal recognition memory, a pattern that is typically observed in frontal and subcortical diseases. Accelerated forgetting was evident on delayed recall tests; the magnitude of this impairment was greater for schizophrenic than for schizoaffective patients. These results suggest that frontal and/or subcortical dysfunction is common to schizophrenia and schizoaffective disorder. A subgroup including the majority of schizophrenic patients, however, exhibit a mild amnesia-like disorder which may result from pathological changes in the structure and function of the temporal lobes or the medial diencephalon.