Evaluation of the clinical efficacy of risperidone for untreated and treated cases of schizophrenia from various aspects.

Author(s): Himei A, Okamura T

Affiliation(s): Department of Neuropsychiatry, Osaka Medical College, Osaka, Japan. psy042@poh.osaka-med.ac.jp

Publication date & source: 2005-10, Psychiatry Clin Neurosci., 59(5):556-62.

Publication type: Clinical Trial

The present study used a diversified approach to the evaluation of the clinical efficacy of the atypical antipsychotic risperidone, and the most appropriate method of switching the medication of patients undergoing alternative therapies; particularly, the widely used typical antipsychotic haloperidol. A study group of 120 patients with CYP2D6*1/*1 was subdivided into an untreated group of 20 (group A) and two groups of 50 previously treated patients (groups B and C) with haloperidol only, for more than 5 years. All patients began risperidone therapy at 2 mg/day b.i.d., increasing in increments of 2 mg to a maximum of 8 mg/day b.i.d., according to their respective PANSS score after each psychiatric evaluation. Group B underwent a tapered changeover in treatment, while group C was abruptly transferred to the new regimen. The results demonstrated that risperidone was effective in 81% of patients, regardless of previous treatment or the method of switching. Twenty patients interrupted their switch treatment for reasons of symptom aggravation. Risperidone was immediately effective against positive and negative symptoms in untreated patients; however, in the previously treated groups, it was initially effective against negative symptoms only; after a 2-week interval, positive symptoms also improved. The previously treated patients required the concomitant administration of an anticholinergic drug. The results of this study provide evidence that risperidone has a favorable profile with regard to efficacy and safety, which makes it a suitable treatment for schizophrenia. Risperidone therapy at the earliest possible stage shows optimal improvement in schizophrenia.