Throughout the play, Macbeth is haunted by the ghost of Banquo, whom he had also killed. The ghost appears to Macbeth during a banquet and accuses him of murder. This hallucination is a physical manifestation of Macbeth's guilt and his fear of being exposed.
Macbeth also experiences sleeplessness, which is a common symptom of guilt. He is unable to find rest and is constantly plagued by nightmares and thoughts of his crime. This lack of sleep further intensifies his guilt and makes him more susceptible to hallucinations and other irrational behaviors.
As Macbeth's guilt grows, he becomes increasingly paranoid. He begins to suspect that everyone around him is plotting against him and that he is in constant danger. This paranoia leads him to commit even more murders in order to secure his position and protect himself.
Macbeth's guilt is a significant driving force in the play and contributes to his eventual downfall. His inability to come to terms with his crime and the consequences it brings ultimately leads to his destruction.