I read a book from my dad when I was younger and have been trying to figure out what it was for years. He has no idea what it was.
It was a post-apocalyptic book where, I believe, the apocalypse involved people snapping and going insane at random. If I remember correctly, the main character's girlfriend/wife goes insane and tries to kill him and he locks her in a bathroom, for example.
It might be set in like a small town trying to survive? And occasionally, members of the town will go insane and kill each other. I can't remember much honestly, it's been about 12 years since I read it.
I believe it's from the '80s, given that that's when my dad was growing up, but I could be wrong.