Elgar Has Had a History of Depressive Symptoms for About

Elgar has had a history of depressive symptoms for about a year, and begins to take antidepressant medications to improve them. A few weeks into his treatment his spouse notices he is unusually enthusiastic. He reports that he wants to travel the world, and if he can't afford the travel he'll "max out our credit cards" and "just go." His spouse says he "seems to be talking and going a mile a minute." The change in Elgar's behavior suggests which of the following conditions?

A) Sundowner's syndrome
B) Absence seizures
C) Unmasked Bipolar disorder
D) Dementia
E) Hallucinations