In a video on her website, she thanked 粉丝 for their support, and 说 she'd been on a "very difficult journey".
The 18-year-old 迪士尼 星, 星级 quit a tour with the Jonas Brothers in November 2010 to get treatment for "emotional and physical issues".
She hasn't 说 why she entered rehab but in November a spokeswoman 说 she had a history of eating disorders.
In the video, Lovato 说 she had been treated for issues that "girls of all ages are dealing with".
'Darkest time'
"I hope to one 日 raise awareness of everything so that I can help people too, just like 你 guys helped me through this rough time," she said.
"I can't tell 你 how much light 你 guys brought into my life in probably the darkest time in my life.
"Without 你 guys I probably wouldn't be here today."
The teenager is a major 星, 星级 in America and dated US pop 星, 星级 Joe Jonas.
She also has her own show, Sonny With A Chance.
She released her debut album Don't Forget in 2008 and the follow-up Here We Go Again a 年 later.
When she quit the Jonas Brothers tour, she had been working on her third studio album, which was due to be released in 2011.
