When I saw this on the cart of books to be weeded from the THS library, I had to read it. Harry and Hortense at Hormone High, copyright 1984. Too perfect to pass up.
I expected a very light, silly book but instead found the story of a teen suffering from deep psychological issues. Jason's parents were killed when he was a child, and to compensate for the trauma, he's convinced that he's the god Icarus.
The story is short but details Harry and Hortense's struggle to deal with Jason's very public delusions. It was actually kind of powerful.