Others in this thread have already addressed some of it, so I'll just point you here:

http://lesswrong.com/lw/ckj/question_about_sociopathypsychopathyaspd/6n95

and here:

http://lesswrong.com/lw/ckj/question_about_sociopathypsychopathyaspd/6npo

and here:

http://lesswrong.com/lw/ckj/question_about_sociopathypsychopathyaspd/6n85

and call it good.

(From personal experience, knowing some people who'd probably score as "mildly psychopathic", there's probably an inner-experience distinction in the same sense that there is with other strong neurological variations, and it can be more or less marked, but the idea that they're "not fully human" seems more like a comforting rationalization, a way of trying to cope with the often profoundly antisocial behavior that high-profile psychopaths appear casually capable of.)