Teen star Demi Lovato is leaving her Disney Channel hit show "Sonny With a Chance", saying that returning after treatment for bulimia and cutting herself would not be healthy for her recovery.

Lovato, 18, who already has two hit albums, told People magazine she would focus on her music in the future.

"It made sense for me to go ahead and leave the show to focus on my music," the actress told People on Tuesday. "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. Being in front of a camera would make me nervous," she added.

Lovato played a Wisconsin teen in "Sonny With a Chance" who lands a main role on her favorite TV show. The Disney Channel series debuted in 2009, and helped make Lovato one of the family friendly cable network's biggest international teen stars.

But she abruptly quit a concert tour with the Jonas Brothers last November and entered a three-month treatment program for emotional and physical issues.

The young star says in an television interview to be broadcast later this week that she developed an eating disorder at the age of eight that led to compulsive over-eating and bulimia, and then started cutting herself secretly at age 11.

"I was compulsively overeating when I was eight years old," she said. "So, I guess, for the past 10 years I've had a really unhealthy relationship with food," Lovato told "Good Morning America", according to excerpts released on Tuesday.

Lovato said she hid her cutting from her family.

"It was a way of expressing my own shame, of myself, on my own body," she said of her self-mutilation from age 11.

Lovato said her efforts to keep her emotions under control reached a boiling point on the tour last year for the Disney Channel musical "Camp Rock 2", and she struck out physically at one of her backup dancers.

"I was performing concerts on an empty stomach," she told "Good Morning America". "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."

The TV interview is to be broadcast on Friday.

Disney Channel said in a statement that it supported Lovato.

"We respect Demi's decision to focus full-time on her music and not immediately return to her acting career. 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," it said.

Disney Channel revamped "Sonny with a Chance" in Lovato's absence last year to focus on other members of the cast. It will start airing new episodes under the "So Random" title in June.