It really depends.

My maternal uncle was a clinical psychologist and worked with the criminally insane.

His contention was that the people in prison were the ones who got caught AND who got convicted - meaning the dumb and disadvantaged.

The smart people who were criminally insane just found a way to mask their crimes, come up with clever crimes, or became satisfied with their lives because they had jobs and careers.

If you look at all the missing people in the USA, you can only draw the conclusion that there are some very seriously sick and clever people running around. Or they become politicians.