zedcutsinger’s review published on Letterboxd:
Vice: Early on in its development, wasn’t Synecdoche being described as a horror film?
Charlie Kaufman: Yeah, that was the initial thing when Spike Jonze and I went to Amy Pascal from Sony Pictures with it. She wanted a horror film from us. So there are elements of what’s scary in the world in the movie, but it’s not really a horror film. Horror is a genre and that means there are certain devices and expectations and certain ways of cutting it and certain music and there are cats jumping out to scare you and shit. There’s nothing like that in this movie. It’s ponderous and it’s weird and it’s emotional, but it’s not a horror movie and I didn’t want it to be. As soon as I sat down to write it I thought, “I’m not going to write that kind of movie. I don’t have any interest in doing that. I want to do something that feels real to me—about what’s scary about being alive, about being a person. And what’s scary about being a person to me is loneliness and illness and mortality and guilt.” So that’s what I put in the movie. Those are things that I think are really scary—along with regret and aging and time passing.
This q&a snippet sums up the movie pretty well.