258 patients who have been treated for at least 3 months with oral olanzapine, risperidone or quetiapine in the treatment of schizophrenia and currently presenting with metabolic syndrome, will be randomized to: i) aripiprazole for 16 weeks, with flexible dosing within a range of 10 to 30 mg once daily (QD); or ii) continue for 16 weeks on the same atypical antipsychotic treatment prior to the study enrollment.