Do I think that calling Sonny a psychopath is a bit much? No, because he was one. Psychopaths are likable and charming. They do, however, lack empathy or guilt. They often act in a reckless and irresponsible manner, sometimes just for the fun of it. Who was banging a bridesmaid at his sister's wedding in front of his wife, his children, the entire family? That's not someone who indulges in high-risk behavior for fun?

Psychopaths are violent by nature, they act impulsively, they are short-tempered. They refuse to accept the consequences of their actions, often blaming others (Pop had Genco; look what I got). The don't learn from their mistakes (just as Sonny never learned to curb his temper), they don't benefit from negative feedback and they can't stop their impulses.