Fifi Geldof suffered with clinical depression since the age of 11

Recalling the moment she thought she was losing her mind as a youngster, she said: "It's confusing and it makes you feel quite lost within yourself.

"It wasn't a slow and gentle descent into depression. Something totally switches in your mind. I'm still trying to work out what's wrong with me now."

The PR ex ecutive - who turned to drugs and alcohol following Paula's death in 2000 from an accidental heroin overdose - admits she has never spoken to her famous dad about her mental state and prefers to turn to her friends when she feels like she's struggling.

She explained to the Daily Mail newspaper: "I never expressly told my parents. Dad doesn't know. I wouldn't talk to him about it now. I don't have that relationship with my family. I lean on my friends a lot more. We are a close family, but I have a different relationship with them than my friends."

Meanwhile, Fifi was left devastated in April when her sister Peaches, 25, died of a drug overdose, and she believes she's had a hole in her soul ever since.

She said: "Peaches' death is like a piece of me that has been taken. A piece of my heart and my soul has gone. She was my baby sister. She knew more than anyone else in the family. Peaches and I were quite similar, mostly in our feelings about stuff that went on that we bonded over. She loved books and reading. We were both quite cynical in our outlook of the world."