[RedMattis]

If humans (and not f.ex. AI) rules the world then inevitably you'll end up with something like:

A rotten old ruler and his rotten court of benefactors. They'll sit there accumulating "corruption" and proclaim that they are "above" the limitations of regular people. At some point they'll get too unstable and start killing each other off, but to keep revolution at bay, much like a Mafia, they'd only bring other unscrupulous bastards into high positions. Last thing you want is getting selfless people with strong morals getting into the mix.

I think it would basically end up similar to real-world corrupted nations and companies. A bunch of narcissists and sociopaths claw their way to the top and kick down to keep better people away. Except unlike the real-life problem with narcissists, sociopaths, and their enablers, these people will get more and more terribly deranged over time. Even "normal people" useful enough to survive will end up deranged over time, perhaps resulting in manic behaviour, or eventually getting killed when they develop a depression and stop being productive.

Either way, it seems like a pretty decent basis for a horror setting. Almost anyone in some position of relative power will be deranged, but there will be lots and lots of young people since loss of human life will get pretty common when the military commanders sit around with stuff like Bloodlust and Megalomania, while the chief of police has Sadism, and again, Bloodlust.

If anything I'd be concerned about it being a bit too corrupt and grimdark. Just about every large company and government agency would skeletons in the closest, perhaps literally messy catacombs in the basement. A number of them would probably not even hide it.

Only if the setting is well aware of the mental corruption and it has high presence in press and media would you get something other than a crapsack world. In that case you'd see a lot of forced therapy and therapy AI monitoring people. Which could get pretty dystopic as well depending on how well this works.