Susan Boyle has spoken of how suffering from Asperger syndrome sometimes leaves her feeling "a sense of panic".
The 53-year-old singer, who was diagnosed with the syndrome two years ago, says she is learning to cope with the condition which makes it difficult for sufferers to communicate.
She told the Daily Mail magazine: "It never happens on stage.
"Off stage, well, it 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.
"That's what I did today. I've learned that it's the only way. And other people have learned that they have to just ignore me. That way I have no one to rant and rave at.
"'I feel a sense of panic, not wanting to be there. I get depressed. I just go away, be myself. Then I come back to you. I always come back."
Asperger syndrome is a form of autism, which is a lifelong developmental disability that affects how a person makes sense of the world, processes information and relates to other people.
Autism is often described as a spectrum disorder because the condition affects people in many different ways and to varying degrees.
Susan was bullied at school in her Scottish hometown of Blackburn, West Lothian and was a difficult child.
Despite these set backs, a fantastic audition on Britain's Got Talent helped catapult her in to becoming an international star who has sung for the Pope, the Queen and at the Glasgow 2014 Commonwealth Games opening ceremony.
Before her diagnosis Susan's unpredictable behaviour was attributed to her having been starved of oxygen at birth.
Now she has a more hopeful outlook on life. She told the magazine: "It's a very difficult subject to talk about because you always feel that eyes are on you, and people view you as different.
"I like to see myself as someone with a problem, but one I can solve. It is definitely getting better."
People with Asperger's can put up barriers up because they do not know how to trust people, but Susan said: "I try not to. I want to let people in."