Mr. Hoffman has always been cautious with his money, but over the past two weeks he has developed grandiose plans to bet his entire life savings on a single horse race. With unrestrained exuberance he has also been giving everybody he sees unsolicited advice on how to make millions in the stock market. Mr. Hoffman's behavior is most indicative of

Mania is a type of bipolar disorder. Mania is characterized by a relatively normal behavior but then suddenly the individual suffers from prolonged periods of abnormal euphoria or irritability, and other extreme behaviors that didn't happen before. Manias present themselves in manic episodes that can last for more than a week.

In this case Mr. Hoffman was probably feeling normal just a few days ago, and suddenly he gets euphoric about having a formula for becoming a millionaire and forgets how he used to manage himself before.