A Study Comparing Three Strategies to Switch Patients With Schizophrenia or Schizoaffective Disorder to Risperidone After Unsuccessful Treatment With Olanzapine.

The purpose of this study is to compare three strategies for switching patients with schizophrenia or schizoaffective disorder to the atypical antipsychotic, risperdone, after they have been unsuccessfully treated with another atypical antipsychotic, olanzapine. In the second phase of this study, investigators will assess the effectiveness of behavioral therapy in reducing body weight in risperdone-treated patients who are overweight or have problems with diabetes or blood sugar.