Alison Brie has been left "helpless and feeling powerless" when struck by depression.

Alison Brie

Alison Brie

The 37-year-old actress went through her "deepest" struggle shortly before she began writing her new movie 'Horse Girl' and also felt angry because of her "genetics", as her grandmother suffered from paranoid schizophrenia.

She said of the movie: "I started to realise this is much more about my fear of having mental illness in my bloodline. When will it come out? And will I have the awareness to know when it's happening?

"In my own personal struggles with depression, I know the feeling of being helpless, feeling powerless, feeling alone. Right before I wrote this, I went through my deepest bout of depression in my life.

"[This was in] 2018, right before we started writing it. I was in a really low place and I started talking to a therapist.

"But then I have this secondary anger at my genetics. Like, 'This doesn't have anything to do with me! How am I trapped in a making of my own mind?' "

The 'Glow' star - who is married to Dave Franco - admitted writing the movie helped her out of her depression, as did her support network and understanding other methods that would help her.

Asked if writing got her out of her depressive period, she told Vulture: "Definitely. There were a number of factors. What I have, that Sarah our character doesn't have, is an amazing support system.

"So many friends and family members of mine go to therapy and take medication. Everyone I know has destigmatised the idea of mental health.

"So it was easy to ask for help, to get out of my house, to get moving and go to yoga class and work out. I work out a lot and I think that really helps keep depression in check."

And penning her own script helped Alison feel "empowered" as it also combated her "career depression" that left her feeling anxious she'd never work again.

She added: "Writing this definitely helped in a career depression kind of way, too. When I'm not working, there can be slumps where I feel like, 'I'll never work again. That was it, I had a good run.'

"So for me it was very empowering to say, 'If I'm feeling uninspired by the roles coming my way or the lack of things coming my way, I'll write the thing I want to perform.' "