AceShowbiz - Sia believes finding fame has played a major role in her battle with post-traumatic stress disorder (PTSD), calling life in the spotlight "the greatest disappointment."

The singer-songwriter launched her music career in the late '90s, and was propelled into the limelight after working on a number of successful collaborations with big-name acts, including "Titanium" with David Guetta, "Diamonds" with Rihanna, and "Wild Ones" with Flo Rida.

She went on to release chart-topping albums "1000 Forms of Fear" and "This Is Acting" but, speaking to Apple Music's Zane Lowe, the "Chandelier" hitmaker insisted that "getting famous should fall under a traumatic category."

"I had a lot of suicidal ideation over the last three and a half years. I couldn't get out of bed," she candidly shared. "I was finally diagnosed with complex PTSD and not a bipolar two."

"So I thought I'd been living with bipolar two, and then I was actually correctly diagnosed as having complex PTSD from a number of childhood and developmental things, and then a bunch of adult trauma as well."

Sia recalled that she used to believe fame would mend everything she deemed wrong in her life, but noted that "when I even got to a level of even average fame, I realised that, that was not the case. And it was so incredibly disappointing."

"As I got progressively, slightly more famous, I realised it wasn't for me at all, and that I had made a huge mistake."

The star, who adopted two 18-year-old boys last year (19), and became a grandmother after one of her kids welcomed two babies, said she suffered a "nervous breakdown," which drove her to wear a wig covering her face, "so that you know I don't want to be famous, and I sent a clear message, and people have been extremely respectful of that message."

Now, "The Greatest" star insisted she's worked through a lot of her trauma, crediting "three years of extreme attachment repair work" for helping her recover.