Demi Lovato admits she was 'a nightmare to work with' before sobriety.

The "Confident" singer candidly addresses her past struggles with sobriety in a new interview withRefinery29, detailing how getting clean has required her to make significant changes in her life.

"I had to learn the hard way that I can’t do parties anymore," the 23-year-old singer reveals. "Some people can go out and not be triggered, but that’s not the case for me."

Telling the publication that at her lowest point, she was unable to go an hour without cocaine, she would resist her parents' discipline by saying, "Try to ground me — I pay your bills."

"Prior to getting sober, I was one of those people who was like, I don’t give a f--k, whatever," she adds. "And I used that as an excuse to do whatever I wanted. I was a nightmare to work with."

Lovato celebrated four years of sobriety in March, telling ET that when it comes to staying clean, "I think what inspires me is remembering that I deserve to be the best that I can be and also knowing people look at me as a role model - it gives me the fire to continue to be strong."

Of course, sobriety is a lifelong battle, and Lovato tells the publication that she had to resist the urge to watch the Oscar-winning documentary "Amy," about the troubled life of late singer Amy Winehouse.