Macbeth is an intense drama wherein the themes of guilt, ambition and the supernatural all conspire to drive Macbeth and Lady Macbeth to commit heinous deeds. They both
respond individually and jointly to the psychological burden of their sins.
From the onset and, having been exposed to the witches (weird sisters), Macbeth goes from a valiant and decorated soldier to a wanton murderer. It was normal in Shakespeare's day for a king to reward his soldiers with titles as a show of thanks for military excellence. Macbeth's seeming misinterpretation - "nothing is / But what it is not" (I.iii.141-142) - of the witches prophesies and not knowing whether they bode "good " or "ill" would probably have led to him "proceed(ing) no further in this business (I.vii.32)." Lady Macbeth's involvement though secures his fate and her own.
It becomes impossible to wash away their guilt and Lady Macbeth's claims that "a little water clears us of this deed" (II.ii.67)is not enough to save her from her own descent into madness.
It seems that whilst Macbeth is driven to commit more and worse deeds, Lady Macbeth, after the ghost of Banquo visits Macbeth, has little hold over him. Her madness is distinct. She tries to deny her guilt by "desexing" herself and removing all emotion from her actions but, as her doctor points out "More needs she the divine than the physician" (V.i.72) as she cannot remove the "damned" spot that ultimately haunts her.
Macbeth's own guilt is misinterpreted as fear and in his attempts to do "all that may become a man" (I.vii.46) to ensure that Lady Macbeth cannot suggest he is a coward, he does not stop at the first murder , despite his initial horrified, reaction "Will all great Neptune's ocean wash this blood..." and must murder anyone who may get in his way or reveal his involvement.
Macbeth's reaction on the death of his wife reveals that his madness has driven him to a state of acceptance of his fate as "it is a tale....signifying nothing."(V.v.26) He is no longer able to rationalize and can think only in terms of where his "vaulting ambition" is taking him and his so-called "charmed" self. He knows he cannot succeed.