The 23-year-old singer - who is the daughter of singer Neneh Cherry and producer Cameron McVey - was gripped by depression and anxiety for "pretty much the whole" of her teenage years and her mum and dad were supportive when her problems led to her dropping out of school.
She said: "I had very big questions about war and death from a very young age.
"They were like, 'It's cool, you feel more, you need to express yourself and be vocal.'
"I had dark thoughts but they were like, 'Here's a piano, make some art.' "
The 'Fine Line' singer still suffers from anxiety but has been able to "piece" herself back together while making her new album 'High Expectations'.
She said "It still comes out to play sometimes, you have this voice when you're depressed sometimes, you have this voice when you're depressed saying, 'You can't do this, you're not good enough for that one person.'
"I make sense of things through writing. It was like building blocks and by the time I finished the album, I was a whole new person in terms of my confidence.
"I realised that I'm OK with the good stuff and the bad stuff - I f**k with it."
And Mabel's song, 'Okay Anxiety Anthem' - which she wrote while feeling "really low"- has "genuinely changed" the way she feels about her struggles.
She told Grazia magazine: "It became this really positive way of looking at anxiety. I used to be ashamed. I didn't know how to explain it to people. But I'm not embarrassed, it's an important part of who I am."
