Why does Lady Macbeth fall apart?

     I think the reason for Lady Macbeth's psychological breakdown is from her mind being permanently traumatized from killing Duncan. Because murdering someone is such a drastic measure to take, the guilt could probably poison a mind beyond repair. I feel like it is evident that all of her sleepwalking is directly related to the things she has done previously in the play. For example, one of the first things she says is from her mind replaying the event of her and Macbeth washing the blood off of their hands after killing Duncan. "Out, damned spot, out, I say!... Yet who would've thought the old man to have had so much blood in him?" (5.1.37-42). Just before her saying this the doctor told the gentlewoman that Lady Macbeth looks like she is trying to wash her hands. This quote highlights that she is in fact replaying that scene in her sleepwalking / sleep-talking. What I believe is Lady Macbeth is going through the same thing that Macbeth went through; how he felt like the blood will be permanently stained onto his hands. So then I think it correlates to Lady Macbeth trying to wash her hands to get the "spot of blood" off. Also, her sleepwalking is also reenacting all the problems she had with Macbeth and how much he was suffering. "Look not so pale. I tell you yet again, Banquo's buried; he cannot come out on's grave" (5.1.65-66). Perhaps all of the portrayals of her trying to talk to Macbeth is playing out in her sleepwalking is that she feels terrible remorse for persuading him to kill Duncan in the first place. Maybe she feels like Macbeth breaking down and having this rampage is all her fault.