The decisions that a person makes can either hurt him or benefit him. In the cases of both Macbeth and Lady Macbeth, their choices definitely caused psychological damage. The guilt that they feel after committing Duncan's murder overtakes them and eventually leads them to constant feelings of anxiousness and remorse. They serve as examples that guilt, ambition, and manipulation can lead to one's downfall. .
The guilt that comes along with committing the murder is too much for Macbeth and his wife to tolerate. Macbeth feels repentance right after he murdered the king. ""Sleep no more! Macbeth does murder sleep"- the innocent sleep- (2.2.34-35). He cannot sleep because he is haunted by recollections of killing Macbeth. After hiring people to kill Banquo, he imagines that Banquo's ghost is sitting at a table during the banquet. He becomes convinced that the spirit is not just a hallucination. His mind has become irrational and distorted, but to avoid suspicion, he tells his people that he has a mental illness and proceeds to make a toast to Banquo. At first, Lady Macbeth does not experience the overwhelming feelings of guilt that her husband feels. She belittles her husband's fears, making them sound unnecessary. "A little water clears us of this deed: how easy is it then!" (2.3.66-67). She warns Macbeth that "these deeds must not be thought after these ways; so, it will make us mad" (2.3.32-33). These words that were once said with confidence and sincerity become ironic as the tale progresses. She, like her husband, experiences sleeping problems. Eventually, she ends up committing suicide. Although it is never stated, it can be implied the guilt she felt became too much and she would rather die than live a life of constant self-reproach. The remorse of killing Duncan corrupts their minds. .
Macbeth's main motive for commiting the murders is his immense desire to become King. His ruthless ambition caused the transformation of the once noble man into a betraying murderer.