The objective of this study is to determine the effect of various mood stabilizers (MS) on the insulin resistance syndrome (IRS; also called the metabolic syndrome) alone and in patients treated with antipsychotic drugs (APDs). Patients will be switched from their current antipsychotic medication to aripiprazole (Abilify) or ziprasidone (Geodon) (unless clinically contraindicated) for comparison with metabolic levels during treatment with the former medication.