Thrillers about insanity/descent into madness

I really like books that have insanity in them, especially when the characters are questioning what’s real or wondering if they’re losing their minds. Stuff like The Shining, Shutter Island, The Silent Patient, etc.

I also enjoyed Psycho, American Psycho, and The Silence of the Lambs.

If possible, I’d prefer for suggestions to be from the 2000’s, but am still open to older stuff if you think I’ll like it! Thanks in advance!

Edit: not sure if this is helpful in any way, but one of my all-time favorite authors is Blake Crouch. I love having my mind bent!