Antisocial Personality Disorder
Antisocial Personality Disorder involves a blatant and pervasive disregard for rules, laws, and the rights of others. It is estimated that 80% of more of prison populations may suffer from this personality disorder.
APD (or ASPD) is one of the DSM-IV Cluster B personality disorder, so it shares many characteristics with Borderline Personality Disorder, Histrionic Personality Disorder, and Narcissistic Personality Disorder.
Antisocial Personality Disorder Web Sites
Wikipedia: Antisocial Personality Disorder
American Journal of Psychiatry collection of articles on Antisocial Personality Disorder
How true and how calculating some people are who have this desease and who will stop at nothing to destroy the lives of those around them for the chance to get their every demand. I suffered and still suffer the after effects of having lived with and been subjected to the actions of one of these psychopaths.
According to Walsh Research Institute, 95% of people with antisocial personality disorder are undermethylated (and also most cases of OCD, anorexia, seasonal depression, schizoaffective disorder, etc.): https://www.vitacure.me/blogs/news/difference-undermethylated-vs-overmethylated-symptoms