Macbeth demonstrates antisocial personality disorder because he does not care who he hurts when he kills Duncan and the others.
The DSM IV describes antisocial personality disorder as “a pervasive pattern of disregard for, and violation of, the rights of others” (Wikipedia). Macbeth killed Duncan, Banquo, Lady Macduff, and others without caring anything about them. They were simply in the way. He described his feelings in an aside when he learned that he was not Duncan’s successor.
That is a step
On which I must fall down, or else o'erleap,
For in my way it lies. Stars, hide your fires;
Let not light see my black and deep desires: (Act 1, Scene 4)
In Macbeth's mind, all that matters is what he wants. A person's life means nothing to him. If he wants something and a person stands in his way, even the king or a loyal friend, then the person must die.
Macbeth feels no guilt at killing Banquo or Duncan. He only fears capture. Unlike Lady Macbeth, who kills herself out of guilt, Macbeth just keeps killing to maintain his position. He does not care that he killed a friend, a woman, or a child.