Cognitive dysfunction in schizophrenia: comparison of treatment with atypical antipsychotic agents and conventional neuroleptic drugs.

Impaired cognitive function is both a feature of schizophrenia and a side effect of conventional neuroleptics. Maze tests were used to determine the effects on cognition of conventional dopamine antagonist neuroleptics (haloperidol and fluphenazine) and the newer serotonin-dopamine antagonist antipsychotics (risperidone and clozapine). Patients on clozapine or risperidone showed better performance on the maze tasks than untreated patients or patients taking conventional neuroleptics. In particular, patients treated with risperidone or clozapine were better able to maintain motor coordination while they focused on the more complex "frontal" maze tasks which required sequencing and planning. In view of the restrictions on the use of clozapine, it is suggested that risperidone should be more widely used in schizophrenia because it preserves cognitive function better than conventional neuroleptics and is therefore likely to allow patients to have better insight into their illness and to have better long-term quality of life expectations.