Demi Lovato Talks Eating Disorder, Leaving ‘Sonny With A Chance’

'For the past 10 years, I've had a really unhealthy relationship with food,' Disney star confides in new ABC News interview.

Demi Lovato surprised everyone when she quit her tour with the Jonas Brothers last fall to seek treatment for “emotional and physical issues .” She recently opened up about those personal issues, which back then caused much speculation about exactly what ailed her, in a new interview with ABC News. Lovato also confirmed that she will no longer be starring in her TV show, “Sonny With a Chance.”

“I’ve spoken openly about being bullied throughout the past few years, but one thing that I’ve never been able to feel comfortable talking about was the effects that it had on my life afterwards,” she said. “I literally didn’t know why they were being so mean to me. And when I would ask them why, they would just say, ‘Well, you’re fat.’

“I developed an eating disorder, and that’s kind of what I’ve been dealing with ever since. I was compulsively overeating when I was 8 years old,” she continued. “So, I guess, for the past 10 years, I’ve had a really unhealthy relationship with food.”

Her eating disorder also gave way to self-mutilation. In the interview, which airs on “Good Morning America ” and “20/20″ on Friday, the Disney star says she began cutting herself at age 11. “It was a way of expressing my own shame, of myself, on my own body,” she told Robin Roberts. “I was matching the inside to the outside. And there were some times where my emotions were just so built up, I didn’t know what to do. The only way that I could get instant gratification was through an immediate release on myself.”

The emotional ups and downs came to a head last summer while on tour with the Jonas Brothers. “I was performing concerts on an empty stomach,” she said. “I was losing my voice from purging. I was self-medicating. I was not taking medication for depression, and I literally was so emotionally whacked out that I took it out on someone that meant a lot to me.”

She is referring to an incident in which Lovato reportedly got into a physical altercation with one of the dancers on the tour. An intervention was staged following that incident, and she entered treatment. “I take 100 percent, full responsibility. I feel horrible. [She] was my friend,” she said. “They sat me down and said, ‘You can’t live like this.’ ” She recalled that once she entered the facility, “For the first time in my life, I started to feel.”

Her sister and her fans acted as her strength as she dealt with the issues she had kept quiet for a decade. “A picture of my little sister [Madison], on my little bulletin board, was one of the main things that kept me going,” she said. “I just kept thinking, ‘OK, set this example for your little sister,’ ” she explained. “The real reason why I’m sitting down with you is to open up the eyes of so many young girls, that it doesn’t have to be this way.”

The same day the preview for the ABC News interview hit the Web, it was announced that Lovato would be leaving her Disney show, “Sonny With a Chance.” “It made sense for me to go ahead and leave the show to focus on my music,” Lovato told People.com. “It’s kind of sad for me that a chapter of my life has ended, but there couldn’t be a better time for me to move on.”

“I don’t think going back to ‘Sonny’ would be healthy for my recovery,” she added. “Being in front of a camera would make me nervous.”

A rep for the show confirms her decision and the network is supporting Lovato’s future endeavors, which include recording for Disney’s record label. “We respect Demi’s decision to focus full-time on her music and not immediately return to her acting career,” a rep explained. “She is a talented young woman and our hearts are with her as she continues to take action to improve her health and bounce back from adversity.”