Susan Boyle speaks out on secret battle with depression

The 'Wilds Horses' singer admitted she is prone to mood swings and fits of anger, saying her condition has its roots in her childhood, when she was bullied.

She said: "I can be up and down like a yo-yo. I can be depressed.

"I know I'm taking a big chance telling people this but you have to be honest. I used to be made a fool of at school. It was psychological bullying and that leaves a scar and it also cultivates a lot of anger.

"When people are a little bit slow others pick at them. My life was made absolute hell."

The 47-year-old star – who led a lonely and reclusive life before she auditioned for UK reality TV talent show 'Britain's Got Talent', after which her audition video became an internet hit across the world – released her debut album, 'I Dreamed A Dream', three weeks ago and has already sold over three million copies, breaking a number of chart records worldwide.

Susan- who suffers from learning difficulties after she was deprived of oxygen at birth - added that performing onstage is the only place she feels comfortable, and can engage with an audience.

She told The Sun newspaper: "I can be a bit funny after being tired but whenever I go on stage I forget all about that.

"I feel I've got a communication with the audience. I'm told I'm a different person on stage."

Susan has previously told how she was beaten "every day" as a schoolchild, and felt "left behind" by the education system in her native Scotland.