What is a ''sociopath''?

Antisocial personality disorder (APD or sometimes ASPD) is a personality disorder which is often characterised by antisocial and impulsive behaviour. APD is generally (if controversially) considered to be the same as, or similar to, the disorder that was previously known as psychopathic or sociopathic personality disorder. Approximately 3% of men and 1% of women have some form of antisocial personality disorder.

A sociopath is a person who, usually due to a congenital brain disorder, but sometimes due to a trauma to the brain suffered at birth, cannot process emotional information the way other people do. They can understand emotion on a logical level, but they don't feel it themselves. The resulting lack of connection to other people, and the terrible frustration this brings, are the reasons for the behavior of a sociopath.