Cognitive dysfunction in schizophrenia, affective disorder and organic brain disease.

We used the Wechsler Adult Intelligence Scale (WAIS) to study a sample of patients with affective disorder (N = 52), schizophrenia (N = 17) and organic brain disease (N = 8). Schizophrenic patients had lower verbal, performance and full-scale IQs than patients with affective disorder, but were no different from those with organic brain disease. An individual WAIS subscale analysis showed that, compared with affectives, schizophrenics had relatively poorer performance on language than non-language tasks. These differences were independent of age, sex, handedness, educational level or drug administration and are consistent with a variety of studies demonstrating significant cerebral dysfunction in carefully diagnosed schizophrenic patients.