Review Question - QID 213651

A 28-year-old man is admitted to the hospital for cellulitis. He has a history of ADHD, chronic back pain, polysubstance abuse, and prior hospital visits for substance-induced psychosis. He is started on antibiotics on the first day, and appears well but complains of anxiety and insomnia that night. On the second day, he is found pacing in the hallway and responding to internal stimuli. He reports feeling frightened by the "wild animals" that he has seen climbing through his window. His temperature is 98.0°F (36.7°C), blood pressure is 140/85 mmHg, pulse is 105/min, and respirations are 19/min. Which of the following substances was this patient most likely using prior to admission?