Lady GaGa struggles with bouts of depression on the road - but her "chronic sadness" helps feed her creativity.
The Poker Face star has found it difficult to navigate her new found fame because her career takes her away from her beloved parents.
The singer admits she often feels low for no reason - but she's learned to channel her unhappiness into her music.
When asked about her lowest point in 2009, she explains, "Loneliness, being on the road. I have a chronic sadness that recurs. The lowest point was in Australia in May. I was overwhelmingly sad, and I didn't know why, because I had all these things to be happy about.
"I went to the studio and played for hours, and I wrote what is going to be the greatest record of my career, a beautiful song about my father. I remember watching the mascara tears flood the ivories and I thought, 'It's OK to be sad.' I've been trained to love my darkness."