Review Question - QID 214727

A 24-year-old man is brought to the emergency department with altered mental status. The patient was with his friends on a camping trip where they admitted to drinking and experimenting with drugs. The patient was found in his room staring at the walls stating that they were "breathing." He has no significant past medical history and takes no daily medication. His temperature is 99.3°F (37.4°C), blood pressure is 132/98 mmHg, pulse is 107/min, respirations are 21/min, and oxygen saturation is 99% on room air. Physical exam reveals a confused young man who states that he can hear the textures of the walls. His gait is stable and he is moving all extremities. Which of the following is the most likely etiology of this patient's symptoms?