The Disney starlet, whose rep had previously said she was getting help for "emotional and physical issues," revealed in the May issue of Seventeen that she had been struggling with cutting, an eating disorder and depression for years.
But Lovato's troubles came to a head in October, when she punched Alex Welch, a dancer on her international tour with the Jonas Brothers.
"Lashing out was my cry for help," the 18-year-old told Seventeen. "Wow, who was I to do that? I'm very ashamed. I wasn't in the right state of mind at all."
Lovato "basically had a nervous breakdown," she said.
"I was really bad off," she admitted. "My parents and my manager pulled me aside and said, 'You need to get some help.'"
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"It was an intervention," she continued. "I wanted freedom from the inner demons. I wanted to start my life over."
Many of Lovato's insecurities had been worsened by her desire to exceed expectations. She told the magazine she once passed out backstage during a concert, but continued to perform after regaining consciousness.
"I didn't want anyone to be able to say that there was someone else working harder than I was," she said.
And, in perhaps a vague reference to her failed romance with Joe Jonas, Lovato said she didn't feel she deserved "to be loved by someone."
"You aren't worthy enough," she would tell herself.
Lovato also went to great lengths to keep her problems a secret.
"There were times when I thought, I don't know if I actually want help because my eating disorders are my best friend," she recalled. "Looking back on it, I just want to cradle my old self up and hold her and tell her that it doesn't have to be this way."
Intense counseling in rehab helped Lovato look at herself differently.
"One of the reasons I was so unhappy for years was because I never embraced my emotions and I was trying to stay in control," she explained. "In treatment, all of the negative things I did were stripped away and I had to start processing my feelings."
In addition to channeling her thoughts into creative outlets like painting and knitting, Lovato also spent her time in rehab rebuilding her friendship with fellow Disney star Selena Gomez, with whom she spoke to each week.
"We didn't really discuss what I was going through — we just talked," Lovato said.
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The "Sonny with a Chance" star, who completed in-patient treatment in January, now wants to use her experiences to help her fans who might be suffering from similar problems.
In a video message released in early March, Lovato credited her fan base for helping her get through "the darkest time in my life."
Through a new project with Seventeen and The Jed Foundation called "Love is Louder Than the Pressure to be Perfect," she will return the favor.
Lovato will take on the role of a Seventeen contributing editor, posting twice monthly at seventeen.com/demilovato and helping to address teen issues in the magazine.
"I'm so excited to be working with Seventeen and The Jed Foundation to help other teens talk about and cope with the problems we all face," she said. "My fans have been such an incredible support system for me — I hope I can repay this and help other girls learn from my experiences."
