Objective: A number of studies have shown that olanzapine and risperidone are more clinically effective than other antipsychotics. Consequently, if a treatment-resistant schizophrenic patient has not received them so far in their treatment history, it would be a sensible choice to use these drugs in treatment before beginning a clozapine regimen. In the present investigation the efficacy and safety of these two atypical antipsychotics were compared with each other.
Method: Sixty schizophrenic patients, allocated randomly into 2 matching groups to participate in a twelve-week, double-blind evaluation for random assignment to risperidone or olanzapine. The chief procedures used for assessment were Scale for Assessment of Negative Symptoms (SANS)' and 'Scale for Assessment of Positive Symptoms (SAPS)'. The Scale for Assessment of Negative Symptoms (SANS)' and 'Scale for Assessment of Positive Symptoms (SAPS)' were used as supplementary measures. Treatment efficacy was evaluated statistically by the use of the t statistic and repeated -measures analysis of variance (ANOVA). Clinical response was defined as a decrease of at least twenty percent in total scores of SANS and/or SAPS.
Results: Both risperidone and olanzapine were significantly beneficial for alleviation of positive symptoms (p<0.001 & p<0.0001, respectively), but only olanzapine improved significantly the negative symptoms (p<0.001). In addition, SAI was boosted significantly by olanzapine (p<0.02). CGI-S had shown significant alterations by both of risperidone and olanzapine (p<0.05 and p<0.04, separately). Finally, risperidone triggered significant escalation of SAS in the related group (p<0.0001).
Conclusion: In this evaluation, risperidone and olanzapine were equally useful in control of clinical symptoms of schizophrenia, but olanzapine demonstrated higher efficiency in comparison with risperidone.