A Comparative Effectiveness Study of Risperidone and Olanzapine in the Treatment of Schizophrenia

Background: Risperidone and olanzapine have each been demonstrated to be efficacious and safe in the treatment of patients with chronic schizophrenia. To evaluate their relative effectiveness, and to better understand the advantages and limitations of each neuroleptic during actual clinical use, we compared one directly against the other.

Method: Forty-two subjects with DSM-IV schizophrenia had received open-label treatment with either risperidone or olanzapine. Symptoms, global functioning, and extrapyramidal side effects before and after acute treatment were compared within and across groups. At 6-month follow-up, the relative effectiveness of these 2 atypical neuroleptics on symptoms and quality of life were further evaluated.

Results: Following an average of 4 weeks of acute treatment, both risperidone and olanzapine were effective in reducing negative, psychotic, and disorganized symptoms. Although both neuroleptics were associated with low occurrence of treatment-emergent parkinsonism, risperidone was more likely to induce akathisia. The measures for parkinsonism were no different across treatment groups, even after taking into account the higher rate of anticholinergic use in the risperidone group. Following 6 months of treatment with these 2 atypical neuroleptics, there was a significantly greater reduction in psychotic symptoms among risperidone-treated subjects. Otherwise, risperidone and olanzapine appear to be equally effective in reducing disorganized and negative symptoms and in improving the quality of life.

Conclusion: Risperidone and olanzapine were equally effective as acute treatments. Risperidone was more effective for treatment of psychotic symptoms at 6 months, but otherwise the 2 medications were equally effective in the routine clinical care of patients with schizophrenia. If low (< 6 mg/day) doses of risperidone are used, the 2 medications have comparable rates of parkinsonian side effects.