Review Question - QID 217720

A 35-year-old man is brought to the emergency department by the police due to aggressive behavior. A witness reports that the patient was found in a public park overturning garbage cans and threatening bystanders. He appeared to be responding to internal stimuli and was talking to himself throughout this episode. In the emergency department, he continues to be combative and requires restraints for medical staff safety. No medical records are available and his medical history is unknown. On physical exam, his temperature is 98.6°F (37°C), blood pressure is 140/80 mmHg, pulse is 134/min, and respirations are 23/min. Examination reveals pupils that are reactive with rotary nystagmus. Which of the following is the most likely etiology of this patient's symptoms?