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Clozapine Improves Cognitive Function in Refractory Schizophrenics

Considerable evidence indicates that atypical antipsychotics improve cognitive function in treatment-refractory schizophrenics. This study examined the long-term effects of administering clozapine to such patients.

Researchers selected 22 patients with a DSM-III-R diagnosis of schizophrenia, active symptomatology, and at least two previous treatment failures on typical antipsychotics or inability to tolerate their side effects. Twelve patients dropped out of the study, leaving seven men and three women who completed both initial testing and retesting at the study's end. Most patients received 600 to 900 mg of clozapine daily. Two patients also received valproic acid and one received clonazepam.

Overall cognitive function significantly improved after treatment, as measured by performance on the Similarities and Digit Symbol subtests and the prorated Full Scale, Verbal, and Performance IQs of the Wechsler Adult Intelligence Scale-Revised. Performance on the Wisconsin Card Sorting Test approached statistical significance.

Comment: These findings are concordant with previous reports of the effects of clozapine on cognitive function in schizophrenic patients. It would certainly be of interest to study larger samples and compare these effects with those of other atypical antipsychotics, including risperidone, olanzapine, ziprasadone, and quieptine.

— C Nemeroff

Published in Journal Watch Psychiatry September 1, 1997

Citation(s):

Fujii DEM et al. The effects of clozapine on cognitive functioning in treatment-resistant schizophrenic patients. J Neuropsychiatry Clin Neurosci 1997 Spring 9 240-245.

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