After watching this former Disney star spin out of control, it's clear she isn't a naive little girl. "I was self-medicating," Demi told Seventeen magazine for their February 2012 issue. "I was doing things like drinking and using [drugs], like a lot of teens do to numb their pain." When news got out that she punched a backup dancer while on tour in 2010, she underwent treatment for her substance abuse, as well as self-harm issues and an eating disorder. Two years later, the singer says she still struggles to stay on the straight and narrow. "I've slipped up a few times, but each time I have learned from it," the 19-year-old star told the U.K.'s Fabulous magazine in April 2012.