Risperidone versus haloperidol in the treatment of chronic schizophrenic patients: a parallel group double-blind comparative trial

A parallel group double-blind comparative trial was conducted to study the efficacy and safety of risperidone compared with haloperidol. After a one-week wash-out, 35 chronic schizophrenic patients (17 males, 18 females) were randomly assigned to one of two groups for eight weeks of double-blind treatment. The patients' psychopathology was assessed by means of the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) and the Clinical Global Impression (CGI). Safety assessments included the Extrapyramidal Symptom Rating Scale (ESRS), the UKU Side Effect Rating Scale, vital signs, body weight, ECG and laboratory screening. Thirty-two patients completed the trial: there were 3 dropouts in the risperidone group. The results on the PANSS and CGI indicate that the mean changes from baseline on the total PANSS score and on the total BPRS score were comparable in both treatment groups. The number of patients where a clinical improvement at least 20% reduction in baseline score was also similar in both treatment groups. Risperidone caused less extrapyramidal symptoms and less side effects in UKU scale than haloperidol. No significant ECG changes were induced, no relevant changes in blood pressure or clinical laboratory parameters were observed. This study has demonstrated that the combined serotonin 5-HT₂ and dopamine-D₂ antagonist risperidone is an antipsychotic as potent as haloperidol. Risperidone causes less extrapyramidal symptoms, and is better tolerated than haloperidol.