 This study hypothesizes that switching to aripiprazole treatment will be associated with reductions in lipid levels and hsCRP in comparison to olanzapine. We hypothesize that aripiprazole treatment will be associated with numerical, but not statistically significant, reductions in comparison to pretreatment with risperidone or quetiapine. We hypothesize that aripiprazole treatment will be associated with no change in comparison to pretreatment with ziprasidone. These hypotheses will be evaluated using fasting lipid profiles and measurement of plasma hsCRP. 