A 17-year-old male is brought to your emergency department by his girlfriend. she states that he has been behaving strangely for the last three days, with rapidly fluctuating moods ranging from euphoric to irritable and paranoid. the patient states that he is fine, just a little nervous about an upcoming test in school. his pulse is 126 beats per minute, bp 182/106, pupils are widely dilated, and he is diaphoretic. what is his most likely diagnosis?