In Act 5 scene 1, what conclusion does the doctor reach regarding Lady Macbeth?

The doctor observes Lady Macbeth's behavior in her sleepwalking incident. He goes to Macbeth and tells him that he is not able to cure her, that she needs God's help to do that. The doctor has realized that it is her conscience that has driven her to this illness, and he would not be able to help her with that.