The psychological community is a bit split on the issue, some see the two as the same problem, others do not. Those that see them as two separate APDs (Antisocial Personality Disorder) believe that though both share lack of empathy as a trait, Sociopaths lack impulse control and organizational skills. Psychopaths don't lack these and can typically function in day to day life without drawing attention to the fact that they are devoid of empethetic skill. It's probably partly behavorial, the psychopath grew up in a stable home and learned to fake empathy with charm to manipulate others, while the sociopath grows up in a troubled home and lashes out without remorse, using charm to go unnoticed by adult authority figures until they do something that can't be ignored, usually killing someone. But then again the theory isn't perfect, not all sociopaths come from broken homes and not all psychopaths come from good ones.