A psychopath explains her diagnostic. The fact that she has no empathy was confirmed by a brain scan. She admits exactly how she functions. She admits that she harms others, lies, steals etc. and she never has any remorse, because she is incapable of feeling any. Yes, such people exist, about 3-5% of the population. As she mentions, there are different types of psychopaths and sociopaths and to different degrees. She is pretty extreme. https://www.youtube.com/watch?v=YKUyw68PNgI