The "Give Your Heart a Break" singer recently signed on to be the face of Be Vocal: Speak Up for Mental Health, an initiative from the National Alliance on Mental Illness and other mental-health advocacy groups, and is opening up about her history with bipolar disorder and addiction.
"I didn't understand why I was going through what I was when I was dealing with all of this, and I realized I could share my story and help others," Lovato told the Associated Press. "If that's my purpose for being on Earth, than that's what I want to do. There's so much more to life than just singing."
She noted that she was "very, very depressed" when she was growing up despite living out her dream. And she couldn't pinpoint what had been upsetting her.
The Disney Channel alum's family staged an intervention and Lovato checked herself into rehab in late 2010 after a string of erratic behavior. When she reemerged, she revealed that she was dealing with an eating disorder, cutting, bipolar disorder and addictions to alcohol and cocaine.
"I'm living well with my mental illness — I am actually functioning like a very happy person would," Lovato told People, adding that she "couldn't be happier" and "life is really, really great."
The actress-singer also credited boyfriend Wilmer Valderrama, 35, for her "positive outlook" and supporting her through her times of need. The "That '70s Show' helps identify "unhealthy behaviors coming into play," she told the mag.
"He's one of those people who's stuck by my side from day one of me getting help and saying, 'Listen, I'm not going to be a "yes" person,' " she said. "Someone that just says 'yes' to you because they're afraid of what will happen to them because they don't want to get out of the circle. "
In March, Lovato marked being three years sober and dedicated an Instagram post to her beau of several years.
"I wish I could put into words how grateful I am for this man right here," she wrote, posting a black-and-white picture of them smooching. "But my love has grown to a level that words could never possibly express how much this man completes me."
The spokeswoman also appeared on the "Today" show on Thursday to advocate for the campaign and thank fans for holding her accountable through her struggles.
"Finally I'm in a great place where I can say recovery is possible," she told co-host Savannah Guthrie. "My fans have really held me accountable, and it's been really incredible to have them as inspirations to stay strong and stay sober as well."