Early on in the play in Act I, scene 5, Lady Macbeth pleads with the spirits to make her bold and fierce, so that she might aid her husband in their murderous plot against King Duncan. In later scenes, she is the one who fortifies Macbeth when his guilt riddles his conscience, making him paranoid and unsure of himself, like in the scene when he sees Banquo's spectre lurking at the feast table.
Toward the end of the play, the audience sees a very different side of Lady Macbeth. Gone is the powerful woman who cried out for the spirits to "unsex me here And fill me, from the crown to the toe, top-full Of direst cruelty" (I.V.42-44). In Act V, scene I, Lady Macbeth has become physically ill, wandering in her sleep, compulsively washing out imagined blood-stained hands, and writing out possible confessions of her guilt. Her overwhelming guilt has physically manifested itself, and she can no longer cope with her feelings or illness. Her death, possibly suicide, is reported to Macbeth in scene V; the audience concludes that since Lady Macbeth found no peace or relief from her guilt in life, she sought it in death.
As was mentioned in the previous post, Lady Macbeth is introduced as a fierce, ambitious woman who encourages her husband to assassinate King Duncan. Lady Macbeth not only devises the plan to murder the king but also participates in the plot by placing the bloody dagger back into Duncan's chamber. Initially, Lady Macbeth is unwavering in her ambition and ridicules her husband for feeling guilty. She tells Macbeth,
"A little water clears us of this deed. How easy is it, then! Your constancy hath left you unattended" (Shakespeare, 2.2.67-69).
Lady Macbeth is initially viewed as mentally strong, determined, and nefarious. However, Lady Macbeth begins to gradually lose her mind as she is overwhelmed with guilt. By Act Five, Lady Macbeth is sleepwalking and hallucinating. While Macbeth is preparing for war, Lady Macbeth wanders the halls at night and continually rubs her hands as if she is trying to wash them. The Doctor witnesses Lady Macbeth say,
"Out, damned spot! Out, I say!—One, two. Why, then, ’tis time to do ’t. Hell is murky!—Fie, my lord, fie! A soldier, and afeard? What need we fear who knows it, when none can call our power to account?—Yet who would have thought the old man to have had so much blood in him" (Shakespeare, 5.1.25-29).
In Act Five, Scene 5, Macbeth learns that his wife has died. Later on in the play, Malcolm mentions that Lady Macbeth may have committed suicide. He says,
"Of this dead butcher and his fiendlike queen, who, as ’tis thought, by self and violent hands took off her life" (Shakespeare, 5.8.71-73).
Lady Macbeth ends up becoming overwhelmed with guilt and essentially loses her mind. She goes from being an ambitious, determined woman to a guilt-ridden, mentally ill queen.