It seems like it was only yesterday that Demi Lovato burst out of Colleyville and onto the national scene -- or, to be more precise, the Disney scene.

But it wasn't yesterday: It was three years ago that Demi Lovato entered the forever-rotating Disney star machine to become primped, prodded and molded into the Next Big Thing to happen since the Last Big Thing.

And, turns out, the road to success has led to some issues for Lovato -- issues such as bipolar disorder, eating disorders and cutting herself, all of which the 18-year-old discussed today in a new interview with Good Morning America, which doubles as her first sit-down since her recent stint in rehab.

Among the bombs Lovato dropped -- in addition to the announcement that she's been diagnosed as bipolar, that is -- was the news that she would be leaving her Disney television show, Sonny With a Chance, in order to avoid body criticism and to focus on her upcoming, third album.

The full interview will air on Friday night on 20/20, which, like GMA is also on ABC and also owned by Disney. For now, though, watch the teaser clip of the Robin Roberts-helmed interview after the jump.

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