Is there a medical condition behind being "evil"?

Sociopathic: The closest would be sociopathic personality disorder in which patients cannot understand or appreciate the concept of right and wrong. They act on what they see as what benefits themselves.

I don't think that : One specific medical condition can be blamed for the evil in the world. However, sadists and sociopaths + psychopaths may behave in ways that the average "man" would consider evil.

Interesting question: There are certainly some people with antisocial personality disorder whose exploitative and devious behavior towards others might be called "evil." however, i think there are some whose behavior is not due to a medical condition but is a conscious choice. Serial killers, career criminals, etc. These may act with extreme cruelty and sadism towards others, and are untreatable with any therapy.