I first used this term on myself when i realized that i needed something to describe how i feel about The Phantom of the Opera. And since RENT lovers (Which I also am) have the term 'Rentheads', I figured I would create the term 'Phantom Junkie'.
"Yeah, yesterday. She's really into theatre."
"Is she really?"
"Yeah, she and her boyfriend are Phantom Junkies. It's funny, because they're just like Christine and Raoul!"