Example to that second point.

Notice how Grey Nasty is a lich.

It takes great power, study, self confidence, fear of death, a fear of no longer existing, and a want for even more power to become a lich. Liches sacrifice so much, just so they can exist a little while longer. 

Grey Nasty would be wildly effective against a mental attack, simply because he's self centered. Just as Schradinger put it;