Psychopaths aren't just born that way...they are also developed by their support groups into becoming so.
We see it with muslim radicals who raise killers of infidels (particularly Jews) and we see it with those in some African American communities who raise children on hatred of Whitey.
Bringing hell up from the depths is not as hard as we previously thought. Satan is quite happy to help on a family by family basis.
Well low IQ and overly high testosterone is not learned behavior or environment.
Long ago Shakespeare wrote about how it could be easy to bring sprits up from Hell and a lot harder to pot them back.