Relationships between medication treatments and neuropsychological test performance in schizophrenia.

Few investigations have assessed the neuropsychological effects of psychotropic medications on schizophrenic patients. In this study, 44 clinically stable schizophrenic inpatients were administered a battery of neuropsychological tests, and their performance was correlated with dosage of neuroleptic medication and benztropine. Neuroleptic dose was correlated with poorer performance on tests of psychomotor speed and attention, and with the number of perserverative errors on the Wisconsin Card Sort. Anticholinergic dose was associated with poorer verbal learning, verbal fluency, and motor speed. Both medication dosages were associated with poorer verbal recognition memory, but this association was strongly influenced by the performance of individuals on the highest medication doses. The findings, which were independent of clinical state and intelligence, indicate that higher doses of neuroleptic and anticholinergic medications are associated with poorer neuropsychological functioning in schizophrenia.