Antisocials are capable of feeling the full spectrum of human emotion. They are typically individuals who were socialized to be criminals, although genetics may be a factor. Children who are exposed to criminal, violent, and/or otherwise antisocial behaviour tend to model that behaviour. They are capable of feeling guilt, but they usually rationalize criminal acts. They believe that their target deserved having been harmed because they "fell for it" and "it's survival of the fittest" or any other such whimsical notion. On the other hand, they do feel guilty for harming one of their friends or family. Gangs are a good example of this. Other antisocials may have been able to feel guilt and empathy, but it was never developed during those essential early years of childhood. This is usually due to abusive or negligent parents. It's more that they can't develop healthy relationships in which trust and empathy can flourish than truly not feeling guilt or empathy.
And then there are the psychopaths... These are the sort that don't feel empathy or remorse at all for anyone. It's a brain abnormality. Primary psychopaths can feel certain emotions to a far lesser degree than most people, and what emotions we do feel are usually fleeting. Complex emotions we're completely oblivious to. For example, I'll jump at loud noises, feel irritated by annoying company, content, interested, etc ... But I'll never understand empathy, horror, selfless love, compassion, etc.
I read a book which stated that secondary psychopaths feel guilt constantly. During childhood, secondary psychopaths were punished regardless of what they did, which lead to high guilt and anxiety that was never associated with a bad deed. It was an interesting concept, but I can't seem to find the book at the moment. If I do, I'll be sure to post bits of it.
