Demi Lovato Stands Up to Cyber Bullies

Last month, after opening up to Good Morning America about her childhood struggles with bullying, and her long-battle with bulimia, anorexia, and self-mutilation, Demi Lovato revealed that she is bipolar.

Now, the former Disney star is using her Twitter account to encourage others to be sensitive to people who suffer from these disorders and diseases. "My heart goes out to any and all women who deal with this daily battle. I can't stand it when people make fun of the diseases so many people struggle from. Not something to joke about," tweeted Demi. "Along with making fun of illnesses or diseases, doing it over the internet only makes you more of a coward. Not to mention you've performed the act of cyber-bullying, something that is equally wrong and unacceptable."

Bullying is a sensitive subject for Demi. The 18-year-old actress-singer was bullied for most of her formative years. "I literally didn't know why they were being so mean to me and when I would ask them why they would just say 'Well, you're fat.' I was bullied because I was fat," Demi told GMA's Robin Roberts last month. She also explained how being bullied as a child led to a series of other problems in her life, including issues with food that have gone on for the last 10 years.

This isn't the first time Demi has used her celebrity to stand up to bullies. In October of 2010, she starred in a PSA for the Pacer's kids against bullying campaign and urged kids to join the campaign on