9. DEMI LOVATO

The truth is, Demi Lovato didn't go to rehab for alleged drug and psychiactric issues; she went, that's right, for Bieber fever. OK, probably not, but work with us here. In 2009, the two had a tweet convo that could've been taken as the beginning of a romance. Yet, obviously, with Justin dating Demi's former BFF, Selena Gomez, they never achieved lift-off. The need for medical attention is entirely understandable with that kind of trauma.