In the first scene of Act V of Macbeth, the Doctor has been called in to observe Lady Macbeth's strange behavior. The hope is that the Doctor can diagnose and treat Lady Macbeth's symptoms and underlying disease. In Act V, the Doctor believes that the symptoms are of a psychological nature and that Lady Macbeth seems like a tortured soul. He suggests that a medical doctor can do nothing for her; instead, she must help herself or hope that God can heal her.
The Doctor is correct, of course, because Lady Macbeth's actions are all manifestations of her guilt. Lady Macbeth only plays a direct role in one of the ruthless murders committed by or ordered by her husband, Macbeth. She definitely does have a hand in persuading her husband to commit the original murder (of King Duncan) that obtained for Macbeth the power that he is currently abusing. After that, Macbeth has his best friend, Banquo, killed and later orders the family of his nemesis, Macduff, murdered (Lady Macduff, their children, and their servants). Even though she was not directly involved in planning or carrying out those latter murders, Lady Macbeth still feels the weight of them on her conscience (such as when she says in her sleepwalking trance that "the thane of Fife had a wife. Where is she now?" (V.i.30).
Again, all of the strange actions performed by Lady Macbeth in Act V scene i are manifestations of her guilt. The Doctor, the Gentlewoman (who has called in the Doctor), and the audience see Lady Macbeth writing secret notes and hiding them, mumbling about and apparently re-enacting moments from the past, and attempting to wash a spot of blood from her hands. Lady Macbeth hallucinates a spot of blood on her hand that she cannot remove despite washing it off repeatedly. She miserably asks, "What, will my hands never be clean?" (V.i.30-31). Here, the audience can see that the imagined spot of blood symbolizes the lasting effects of the crimes the Macbeth and Lady Macbeth have committed. Soon after this, Lady Macbeth commits suicide because she is so tormented by memories of what she and her husband have done. She can only escape her guilt through her death.
There are several strange physical symptoms of Lady Macbeth’s troubled conscience that are witnessed by the doctor on Act V Scene i.
Firstly, he sees her sleepwalking with her eyes open-
A great perturbation in nature, to receive at once the
benefit of sleep and do the effects of watching!
The next action is that she is moving her hands as if washing them-
Look how she rubs her
The doctor is also concerned that she is talking as she moves-
Hark, she speaks!
These physical symptoms together demonstrate a profound mental disturbance. As Lady Macbeth is clearly talking about a crime involving a death and blood, it is obvious that she has more than a medical complaint to deal with. The doctor decides that she -
More needs she the divine than the physician.