A 35-year-old man with schizophrenia presents with complaints of frequent urination, abnormal thirst, and increased appetite. He has been taking olanzapine 20 mg at night for the past 3 years to treat schizophrenia, without ill effect except for weight gain. The only other medications he takes are lisinopril and amlodipine for hypertension. He smokes 25-30 cigarettes per day but has started on nicotine replacement therapy in the form of a patch. The patient has unintentionally lost 10 lb in the past 2 months. He is 5 ft 10 in and weighs 210 lb (BMI 30.1). A metabolic panel reveals a hemoglobin A1c level of 7.2% and a fasting plasma glucose level of 131 mg/dL. He is diagnosed with type 2 diabetes (T2D) and is started on metformin.