Altered mental status, also known as certifiably off your rocker.
I chose this because it is a favorite admitting diagnosis of ER doctors that have no idea what is wrong with someone. Of course if someone is confused they end up right on my floor!
I dedicate this to all my lovely elderly friends that I spend the evening hours taking care of. That tell me how much they miss their long gone grandparents and parents, that still remember the first time they met their spouse of 60 years like it was yesterday. That sometimes scream and yell and try to rip my hair out. My job is never boring.