Psychopaths are associate with psychopathic personality disorder. Sufferers of the psychopathic personality disorder show traits and symptoms of antisocial personality disorder, narcissistic personality disorder and/or paranoid personality disorder. Therefore, they have a lack of empathy and guilt, and an absence of deep emotional connections; as practical results, they tend to be extremely violent and twisted. This also means that they cannot be remorseful, exceptions aside.

Psychopaths, as stated by Lecter's quote above, are NOT crazy or psychotic, and are often mistaken by being so. Psychopaths are completely aware of reality while psychotic people are polar opposites; they hear voices, hallucinate, and often do not fully understand what they are doing.

Sociopathy is a version of psychopathy. Psychopaths however are often more intelligent, while sociopaths are good liars who don't have many feelings, but understand others feelings way too much. A lot of sociopaths have a facade they use in order to blend into society. However, this does not mean that every sociopath is villainous, in fact, most sociopaths in real-life are people living a completely normal life, and in fiction, some may even be heroic (though they are antiheroes).

Psychopathy is usually a persistent condition from birth, but it can be induced by a succession of horrific event that twisted the sanity of said characters.

Also, just because a villain is Vengeful or Wrathful and therefore adapt violent tendencies doesn’t necessarily make them Psychopaths unless they are particularly antisocial in nature.

NOTE: Not to be confused with its good counterpart.