There's a mod for Fallout: New Vegas called DUST, in which pretty much every NPC is hostile, there are almost no ready sources of shelter, ammunition, food, or clean water, the mutated wildlife is everywhere, and even more invasive species of hostile wildlife have been introduced. It basically turns it into a survival horror game.
One of the only food staples is either meat from irradiated wildlife or... other humans. Insanity is a game mechanic in the mod, and it has both extreme negative and positive effects on your character, including auditory and visual hallucinations.