In case of psychopathy, or better anti-social personality traits in general, there is some research into this, and it indicates that "genius level" intelligence

In case of psychopathy, or better anti-social personality traits in general, there is some research into this, and it indicates that "genius level" intelligence is a protective factor. So a person with amoral/anti-social traits and very high score on the G factor (I think) is able to compensate, high cognitive abilities can sort of inhibit amoral impulses through sheer brute force of intellect, sort of. This makes sense because anti-social/amoral behaviour is in the general case not very adaptive and beneficial (for each successful psycho, you have vastly more of them leading miserable lives). Also, the relationship is non-linear, it only works for very high levels of intelligence. I'd love to give you some reference, but unfortunately I don't have the literature at hand ATM.