Demi Lovato believes she has shown her true ''strength'' by overcoming her ''demons.''

The 'Heart Attack' hitmaker, who sought treatment in rehab for bulimia, a self-harming disorder and addiction in 2010, says ''eating disorders do not discriminate'' and she wants to clear up misconceptions about mental illness.

In lengthy post on Twitter, the 22-year-old star wrote: ''Having an eating disorder doesn't show 'strength.' Strength is when [you] are able to overcome your demons after being sick and tired for so long.

''There's a wide misconception that anorexia and/or bulimia is a choice and you often hear people say things like 'why doesn't she just start eating?' Or even 'just stop throwing up.' It's the ignorance and lack of education on mental illnesses that continues to but mental health care on the back burner to congress even though this is an epidemic that is sweeping our nation, and causing more and more tragedy every day (sic).''

She added: ''Eating disorders do not discriminate.. Neither does any other mental illness. These are deadly diseases that are taking lives daily.

''It's time we start taking mental illness as serious as physical illnesses.''

Demi's comments come just days after revealed she plans to continue to embrace being a role model.

She said: ''I want to use my voice for good and I know that I can do a lot other than singing. And that's what I want to do. That's what I want to show people.''