But according to Lovato, it was Barney who helped her get through the pain.
"I guess subliminally, I did have a relationship with this figure that was saving my life in a way," the singer says.
"I've talked about being bullied and the years of being a teenager, but I went through things when I was younger that I've never talked about that probably caused me to turn out the way I ended up turning out."
Lovato also touched on her upcoming birthday milestone.
"I look at birthdays as celebrating another year of life," she says. "You've made it another year. An entire year. Some people don't make it to 21."
For more on Demi's Cosmopolitan interview, pick up the issue on newsstands July 9 or head over now for a sneak peek on cosmopolitan.com.