The influence of risperidone on cognitive functions in schizophrenia.

Introduction of the antipsychotics of the second generation (SGA) into the therapy of schizophrenia roused expectations that, finally, the cognitive dysfunction in schizophrenia could be eliminated by psychopharmacological therapy. The purpose of the study was to verify the effect of atypical antipsychotic risperidone on cognitive functions in schizophrenic patients. The study was carried out upon 48 male schizophrenic patients aged 21-47 years who were switched from the antipsychotics of the first generation (FGA) to the antipsychotic risperidone, due to intolerance, during the treatment. Intelligence, abstract and concrete thinking and mental speed, attention, and short-term non-verbal memory prior to the switch, one month after the switch, and three months after the switch to risperidone, were evaluated. One month after the switch the number of subjects with severe impairment of intellectual abilities decreased significantly from 62% to 15% and after three months the number was even lower-8%. The impairment of concrete and abstract thinking and mental speed also showed the same tendencies of decrease. The improvement of the cognitive functioning after the switch from the antipsychotics of the first generation to the antipsychotic risperidone is explained by removal of the antipsychotics of the first generation from the therapy and the consequential disinhibition of secondary cognitive impairments and by decreased average dose of anticholinergic and decreased number of patients who need anticholinergic therapy beside risperidone. The possibility of clear pro-cognitive effect of risperidone is suggested and its verification is proposed with strict control of other factors that improve cognitive functioning of schizophrenic patients during the treatment.