In a video on her website, she thanked प्रशंसकों for their support, and कहा she'd been on a "very difficult journey".
The 18-year-old डिज़्नी तारा, स्टार quit a tour with the Jonas Brothers in November 2010 to get treatment for "emotional and physical issues".
She hasn't कहा why she entered rehab but in November a spokeswoman कहा she had a history of eating disorders.
In the video, Lovato कहा she had been treated for issues that "girls of all ages are dealing with".
'Darkest time'
"I hope to one दिन raise awareness of everything so that I can help people too, just like आप guys helped me through this rough time," she said.
"I can't tell आप how much light आप guys brought into my life in probably the darkest time in my life.
"Without आप guys I probably wouldn't be here today."
The teenager is a major तारा, स्टार in America and dated US pop तारा, स्टार 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 साल 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.
Go Team DEMI!!!!!!!!!!!!!! Though I <3 Selena TOO!
