Movies about mental illness that are actually made by people suffering from that (or at least they feel like it)

I've always been interested in outsider art, and reading the thread on films about mental illness made me realize that many of those don't really feel authentic, they're big productions that just use those topics. Which is fine, I believe in the right of cinema to do whatever it wants. However, I'm more interested in explorations of mental illness that feel like they were made by someone actually going through similar stuff, maybe the directors said so themselves. A couple examples:

Possession (1981), written by Zulawski when he was going through a divorce (and it shows).

Antichrist (2009), written by Von Trier when he was going through intense depression (and it shows), also presents an interesting framing of nature and the world as chaotic evil.

The Evil Within (2017), made over the course of many years by a rich mentally ill man (not a professional film director) based on his nightmares.

If you have other examples, I'm curious! Extreme/weird cinema is welcome as well, it doesn't have to be typical horror necessarily.