Review Question - QID 210423

A 27-year-old man is brought into the emergency department by ambulance. The patient was at an appointment to receive welfare when he began acting abnormally. The patient was denied welfare. Shortly afterward, he no longer responded to questions and stared blankly off into space, not responding to verbal stimuli. Other than odd lip-smacking behavior, he was motionless. Several minutes later, he became responsive but seemed confused. The patient has a medical history of drug abuse and homelessness and is not currently taking any medications. His temperature is 98.9°F (37.2°C), blood pressure is 124/78 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam reveals cranial nerves II-XII as grossly intact with 5/5 strength in the upper and lower extremities and a stable gait. The patient seems confused when answering questions and has trouble remembering the episode. Which of the following is the most likely diagnosis?