Behavioral Science & Ethics USMLE Step 1 Practice Question

A 47-year-old woman with no prior psychiatric history presents to the emergency department with her husband, who reports acute onset of disorganized speech, visual hallucinations, and paranoid delusions over the past 5 days. He notes she has become increasingly irritable and has barely slept in 2 weeks. On review of systems, he mentions she has gained 20 pounds over 4 months despite dieting and complains of constant fatigue and muscle weakness. On examination, she appears cushioned facially with truncal obesity and proximal muscle weakness. Vital signs show BP 156/94 mmHg, HR 102/min, RR 16/min. Skin examination reveals purple striae on her abdomen and easy bruising on her extremities. Neurologic examination is nonfocal. Urine drug screen is negative. Labs show sodium 145 mEq/L (normal 135-145), potassium 3.2 mEq/L (normal 3.5-5.0), and glucose 156 mg/dL (fasting). Which of the following is the most appropriate next step in evaluation?