The patient: A 16-year-old girl in CaliforniaThe symptoms: The teenager was referred to an emergency department because she was having hallucinations, including seeing a flying green dinosaur and hearing voices telling her to hurt others. She also had a sense that she was being followed.In the emergency room, she was trembling and sweating and had a racing pulse and shallow, fast breathing. She did not have a fever, although she did have one at the hospital that had referred her.During her conversations with ER clinicians, the teen reacted to the vision of the dinosaur as though the creature were present in the room. She reported that she had experienced these hallucinations since seventh gr...