Lovato230.jpgDemi Lovato has revealed that she suffers from bipolar disorder, People magazine reports.

The actress, 18, quit her tour and entered a treatment center in November after punching one of her dancers. Lovato says her three-month rehab stay, where she underwent therapy for anorexia, bulimia and cutting, is also where she discovered that she was bipolar.

"Looking back it [the diagnosis] makes sense," she says. "There were times when I was so manic, I was writing seven songs in one night and I'd be up until 5:30 in the morning."

Last week Lovato tweeted a message of support to actress Catherine Zeta-Jones, who just opened up about her struggles with bipolar disorder and checked into a rehab facility earlier this month.

"I feel like I am in control now where my whole life I wasn't in control," Lovato says.