Question: why wasn’t Bilbo affected like Frodo was? He had the ring much longer, and also never seemed to be hunted by those ghostly horsemen either.
Mind you I’ve never read the books, so I feel like I’m missing something the movies never explained.
Basically Frodo comes in as Sauron is gaining strength, and desperate to regain the One Ring. So there's more 'pressure' being put on Frodo, just because of when he came into possession of it (or rather, when the movies take place, as in the books he inherits it a number of years before even leaving the Shire).
It's also a factor that he's getting closer and closer to Mordor right? Not to mention he was hungry, exhausted, sleep deprived, etc. with the ring physically near him 24/7. I haven't read the books in a couple years so my memory is sketchy.
I haven't read it in years either, but that sounds correct.