Demi Lovato says her bipolar disorder is a daily struggle.

The 'Neon Lights' singer has faced numerous hurdles in life, including battling an eating disorder, drug and alcohol addiction and self-harm, and she credits medication and positive thinking for helping keep her manic-depressive illness in control.

She told Cosmopolitan for Latinas magazine: ''It's a daily thing. I treat it with medication. Not everybody does that, but for me it works. That's what works for me - medicating, checking in with people, being honest, and being grateful for things.''

Demi, who was named 'Fun, Fearless Latina of the Year' by the magazine, claims her main career motivation is being a good role model for her younger sister, 'Desperate Housewives' child star Madison De La Garza.

She explained: ''When I was younger, I needed someone in the spotlight to idolize, who stood for positivity and light and happiness, and wanted to change the world. And because I didn't have that, I realised, I want to do that, if only for my 12-year-old little sister.''

The 21-year-old star proudly revealed her birthday last summer was a turning point in her life because she was happily sober for the first time in years.

She explained: ''I was used to drinking and doing drugs on my birthday. I always imagined my 21st being a huge party where I'd get s**t-faced and go crazy. But I realized that there's so much more to life than that.''