This chapter provides a summary of the landmark Comparison of Antipsychotics for Metabolic Problems trial on schizophrenia treatment. This trial was designed to help clarify some of the clinical considerations in choosing antipsychotics. Does switching to aripiprazole from olanzapine, quetiapine, or risperidone confer metabolic benefits? Does the switch to aripiprazole cause clinical destabilization? Starting with these questions, it describes the basics of the study, including funding, study location, study population characteristics, how many patients, study design, study intervention, follow-up, endpoints, results, and criticism and limitations. The chapter briefly reviews other relevant studies and information, discusses implications, and concludes with a relevant clinical case.