Measurement of simple reaction time in antipsychotic treatment of patients with schizophrenia

The role of simple reaction time in schizophrenia has been extensively reported to date in professional literature. However, most studies have examined basic reaction time under static conditions using a single measurement. The aim of the present study was to establish whether any changes occur in simple reaction time during treatment with risperidone or olanzapine in in-patients suffering a relapse of schizophrenia. Seventeen in-patients suffering acute relapse of schizophrenia (DSM IV criteria) and twenty matched, healthy controls participated in an eight-week, double-blind pilot study. The patients were treated with conventional antipsychotics for seven days after admission and were then randomised to the treatment arms with risperidone (4 mg/day) or with olanzapine (10 mg/day) at a fixed dosage in the first week and thereafter in flexible dosages for the remaining seven weeks. Since no differences were found between reaction times of patients treated with risperidone or olanzapine, the two treatment groups were merged in the statistical analysis before being compared with the normal controls. Psychopathological symptoms were assessed using the Positive and Negative Symptom Scale (PANSS) and extrapyramidal symptoms with the Simpson Angus Scale and Abnormal Involuntary Movement Scale. Reaction time was measured with the Alpha apparatus, connected to a personal computer. All assessments and measurements were conducted four times during the treatment phase of the study. The reaction time of patients was significantly longer than that of the healthy controls (t1 = 17.11; p1 < 0.05). After eight weeks of treatment the reaction time of patients significantly improved but did not reach that of the healthy controls (t4 = 28.18, p4 < 0.05). Furthermore, the improved reaction time in the patients did not correlate with improvement of psychopathological symptoms or with improved extrapyramidal symptoms. The results of the study suggest that simple reaction time can improve during treatment with atypical antipsychotics.