A 35-year-old man from Mumbai presents to the emergency department brought by his wife after a 2-week episode of markedly elevated mood, grandiose delusions (believes he is a reincarnation of a Bollywood director), complete lack of sleep (sleeping 2 hours/night but denying fatigue), rapid pressured speech, and reckless spending of ₹10 lakhs on a car he cannot afford. He has been unable to work and his wife reports he has become verbally abusive. Three years ago, he had a depressive episode lasting 6 weeks treated with fluoxetine. There is no prior history of elevated mood episodes. Mental status examination shows psychomotor agitation, flight of ideas, and the aforementioned grandiose delusions. What is the most likely diagnosis?