Susan Boyle Confesses Asperger's Syndrome Makes Her Feel Like 'King Kong's Mother'

11/15/2014 AT 02:45 PM EST

On stage she feels "safe," but it's life out of the spotlight that's difficult for Susan Boyle.

Boyle's been described as eccentric all her life, but last year she was finally able to put a more precise label on the reasons for her volatile behavior: Asperger's. The singer was diagnosed with a mild form of autism in December 2013, but her mood swings – including unpredictable tantrums preceded by a "hooded look" like clouds descending over her face – is still very much a work in progress.

The unlikely star, whose 2009 audition for Britain's Got Talent brought her international fame, admits that because of her condition, she's "the only artist who needs a leash! I'm King Kong's mother!"

In an interview with Britain's Daily Mail , Boyle, 53, acknowledges, "Off stage, [my bad behavior] happens lots. It always has. But I'm getting better at dealing with it because I know what it is. If I feel I'm going to take a mood swing, I get up and leave." Boyle says that the tantrums stem from "a sense of panic, not wanting to be there."

"I get depressed," she explains. "I just go away, be myself. Then I come back to you. I always come back."

Performing remains Boyle's safest haven. "It never happens on stage," she notes. "It seems to make me feel better … When I'm up on stage, even if I've had a bad day, I can become a different person. I feel safe." In the footlights, she says, "I don't feel judged up there. I feel accepted."

Boyle, who just wrapped up a U.S. tour, hopes she can bring some of the peace she feels on stage to her everyday life, but admits it's a process. "I like to see myself as someone with a problem, but one I can solve," she says. "It is definitely getting better. Since the diagnosis I've learned strategies for coping with it, and the best one is always to just walk away."

The Grammy nominee, who has sold more than 19 million albums worldwide, also wants to use her unique position as an educational opportunity. "I want people to see how it is, to see that you shouldn't judge." She adds, "People with Asperger's do put a barrier up because they don't know how to trust people. I try not to. I want to let people in."