Impact on cognition of the use of antipsychotics.

Cognitive dysfunction is recognised as one of the more enduring deficits in schizophrenia. The syndrome is associated with impairment of the temporal and frontal regions of the brain that are concerned with cognitve function, as well as subcortical regions that are closely interconnected with them. Cognitive dysfunction may underpin some of the psychopathology of schizophrenia, as well as contribute to the patient's impaired social and vocational functioning. Cognitive deficits are relatively independent of psychotic symptoms in schizophrenia, and are probably central and enduring features of the disorder. It must also be considered that cognitive disability may be rate-limiting to the schizophrenic patient's rehabilitation and impairs quality of life. Although there is a general consensus that neuroleptic drugs are able to improve the psychopathology of schizophrenia, there is continued debate concerning their impact on cognitve function. Chronic treatment with classical neuroleptics has been reported to produce only minimal improvement in, and may actually impair, cognitive function in schizophrenia. In contrast, novel antipsychotics seem to cause less cognitive impairment than classical antipsychotic medication and may improve cognitive function. Whilst in the past research focused on the development of clinically effective antipsychotic drugs with a reduced propensity to cause extrapyramidal symptoms (EPS), it is now being recognised that maintaining and enhancing cognitive function and improving quality of life should be the goal in the treatment of schizophrenia.