The Pop-Tarts Crazy Good Summer concert performer, 20 – who completed treatment for emotional and physical issues in January 2011 – opened up about substance abuse more than a year later, explaining, "Promoters gave me drugs and alcohol in restaurants or clubs. They wanted me to come back so I would be seen there … Being a celebrity can be dangerous. Nobody says 'no.' That's why so many end up overdosing and dying. It could definitely have happened to me."
Now, with news of Monteith's death from a mixture of heroin and alcohol, The X Factor panelist, who launched the Lovato Treatment Scholarship Program in June, hopes this tragedy will at least spread awareness.
"All it takes is one moment of vulnerability to get slipped into your addiction," she told PEOPLE Wednesday. "It's not a choice. Nobody chooses to use. He didn't choose to die. It was the disease. It can creep up on you at any moment. It only takes one moment of relapse to potentially die. It's really scary, but I'm really hoping that from this, people are able to see this is a very, very, very dangerous disease."
The "Made in the U.S.A." singer, who says she deals with her issues daily, acknowledges she can't do the same things as the friends she considers "normies."
"They can turn 21 and have their turn-21st-birthday," she says. "I don't think that I – I just don't put myself in those situations where I'm going to be at those 21st birthdays. I don't go to clubs. I just know it's something I can't do without being triggered. And that's okay."
Lovato, whose heart is "really, really broken" over the fallen Glee star, 31, says she especially feels for his girlfriend, Lea Michele.
"The main person in my thoughts is Lea," Lovato says. "I am praying for her so hard and I love her so much. I'm wishing her a lot of strength right now."
Fans of Monteith's may make donations in his name to three charities that were especially important to him: Project Limelight Society, which exposes youth living in Vancouver's Downtown Eastside to the arts; Virgin Unite, founded to support entrepreneurial efforts to better the world; and Chrysalis, which helps homeless and low-income individuals find employment.