An example of Macbeth’s disturbed mind is his reaction after he kills Duncan.
Lady Macbeth has convinced Macbeth to kill Duncan, but it seems that the deed does not sit easily with him.
After Macbeth murders Duncan, he hears one of the guards call out “in’s sleep” the word “Murder!” Macbeth is concerned that he has been discovered.
One cried, “God bless us!” and “Amen” the other,
As they had seen me with these hangman's hands.
Listening their fear, I could not say “Amen,”
When they did say “God bless us!” (Act 2, Scene II, p. 29)
This is not the beginning of his hallucinations or visions. After all, it was the vision of the bloody dagger the spurred him on the kill Duncan. Yet this is the first vision that seems to really disturb him. Whereas the other vision gave him courage, this one just makes him concerned.
Guilt and fear seems to be touching Macbeth. He worries that he has been discovered, or he feels guilty for killing Duncan.