Lady GaGa reveals her "chronic sadness"

Lady GaGa has admitted that she has been experiencing "chronic sadness" this year.

The 'Bad Romance' singer told OK that she often finds it difficult to cope with being away from home when she goes on tour.

Discussing the impact of her recent success, the star explained: "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."

However, GaGa added that she was grateful for the experience because it helped to boost her creativity.

She said: "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 okay to be sad'. I've been trained to love my darkness."