At 15, she was treated for depression

The model has finally spoken out about the depression and alienation she suffered in her teenage years.

Cara Delevingne believes it is necessary to talk about mental illness and this is the reason she decided to include the subject in her new novel Mirror, Mirror.

The 25-year-old actor, who suffered from depression as a teenager, explores the themes of substance abuse, abusive parents and other issues which affect mental health in her new young adult novel, reports Contactmusic.

"I think it's really important that in this book, and generally, that mental illness is talked about.

"I think my depression came from a mixture of things, whether it was from pressure from, not only myself, but to do well in school, from my parents to get good grades, and to be someone I thought I was that I wasn't.

"You bottle so much up, you end up going mad.

"When you bottle emotions up that's when it leads to (your) downfall," says Delevingne.

The Paper Towns actor says she still wishes that she was more aware of mental health during her hard times.

"I wish I knew how important it was to reach out to people, to talk to people about how I felt.

"(To) talk about my emotions more and not run away from myself...

"To open up and not hide my feelings. Create more, learn more, take everything in because every moment is magic."