Don't get me wrong, there are a lot of metaphors in this film, but the most important one is this.
Just say no to Harry Styles.
Wow. Fight me, this movie isn't about mental illness.
In all seriousness, I would have wanted to make this. It's drama, it's sci fi, it's a wierd character study, and I just love it.
I personally feel that there is way too much care put into the details and the symmetry of symbols in the film to be taken as "she was just mentally ill". I think the truth is exactly what the character claims. It might not be, but…