This is a multi-site, 12-week, open-label study assessing the weight and metabolic changes associated with lurasidone treatment. Antipsychotic (AP) naive subjects will start open-label treatment by following a flexible titration schedule. Quasi-antipsychotic naive subjects (less than 4 weeks of total AP treatment) will be started on lurasidone and tapered off the other antipsychotic over an estimated 4 weeks depending on the dose and tolerability of the prior antipsychotic. Other psychoactive medications including antidepressants, benzodiazepines, stimulants, alpha-2 agonists, and mood stabilizers are allowed as long as the dose is not changed, unless it is clinically necessary. Assessments of weight, efficacy, and side effects are conducted at baseline, week 2, week 4, week 8, and week 12. The primary outcome is percent change in weight. The secondary outcomes include psychiatric efficacy measures and side effects.