Assuming some underlying truth to it, it makes sense

You see enough shit, you start thinking about how damn brutal the world is.

You start thinking about that, you start struggling to make sense of it all.

You realize you can’t, because it isn’t sensical in the first place.

Thus, you have to face down the screaming in your head just to function

At some point, you either learn to joke about the ugliness, or you eat a bullet.

The “smarter” someone is, the more likely they are to examine things beyond the surface, so the more likely they are to see the darkness beneath it all, and reach that breaking point.