The effects of clozapine on cognitive functioning in treatment-resistant schizophrenic patients.

This study examined the cognitive functioning of 10 treatment-resistant schizophrenic patients after a minimum of a 1-year trial on clozapine. Results indicated significant improvements on prorated Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full Scale, Verbal, and Performance IQs and on the WAIS-R Similarities and Digit Symbol subtests. A trend was also found for improvement on the Wisconsin Card Sorting Test.