The statement did not specify the 18-year-old's problems, but said Lovato checked herself into a facility to address the concerns.
A person familiar with the situation previously told The Associated Press that Lovato entered treatment for problems including an eating disorder and cutting herself. The person, speaking on condition of anonymity because they were not authorized to speak publicly due to the sensitivity of the matter, later clarified the statement, saying Lovato had dealt with those issues in the past.
Lovato, who is star of Disney's "Camp Rock" movies and the sitcom "Sonny With a Chance," was on an international tour as a special guest of the Jonas Brothers, but left the tour over the weekend to enter an undisclosed facility, according to the statement.
"Demi has decided to take personal responsibility for her actions and seek help," the statement said. "She is doing just that. Demi and her family ask that the media respect her privacy during this difficult time."
In a 2009 interview with The Associated Press, Lovato, who has also released several records, said she had to leave middle school at one point because she was bullied so badly.
"It was more verbal harassment than physical abuse, but that's actually more scarring than anything," she said. "And I had to leave because I just couldn't deal with it. And I've home-schooled ever since."
Lovato was linked earlier this year to Joe Jonas, her "Camp Rock" co-star, but the two later broke up and said they remained friends.
Her rep said Lovato regretted not finishing the tour but "is looking forward to getting back to work in the near future."