Madness is a theme in Macbeth which destroys Lady Macbeth and is responsible for Macbeth's delusional, irrational and impulsive behavior. Shakespeare presents this theme by revealing how guilt drives their madness; Macbeth becomes all the more ruthless as time passes and Lady Macbeth becomes more obsessive, especially regarding the "damned spot" she refers to in Act V, scene i, line 33 and which she tries to remove with ever increasing intensity.
The theme of madness in Macbeth would reveal itself sooner to a modern audience than a seventeenth century audience because the modern audience would be so much more aware of the signs and symptoms of mental conditions. In terms of the play, an audience from Shakespeare's day might have little patience and might anticipate a resolution quite different from a modern audience which would consider the circumstances, the personalities and the triggers before judging the characters.
Both Macbeth and Lady Macbeth have very competitive streaks in them and obsessive personalities, evident in their inability to wait for circumstances to change naturally. They feel that they need to take control. At the beginning, Macbeth is still able to reason and concludes that Duncan does not deserve to die at his hand; he recognizes his own "vaulting ambition," which he refers to in Act I, scene vii, line 27. However, he is unstable and is affected by Lady Macbeth's obsession which is so overwhelming that she cannot control her actions, even begging to have all her nurturing instincts removed to ensure her resolve, to make her capable of "direst cruelty" (I.v.40).
A contemporary audience would attribute a name more readily to the disorder (for example, Macbeth shows signs of schizophrenia) and would want to use medication to alleviate the symptoms whereas a mental asylum would soon be assigned to a patient in Shakespeare's day and the brutal treatment of the insane, during that time period, is well-documented. To a seventeenth century audience, there would also be questions about the supernatural element, especially in view of the witches' part in Macbeth's downfall. As for Lady Macbeth's madness, even her doctor notes that he cannot help her and that only some sort of heavenly intervention or miracle can save her. As he says in line 72 in Act V, scene i, "More needs she the divine than the physician." He can help her no further.
To an audience from the seventeenth century, the end would be appropriate as the deaths of both Lady Macbeth and Macbeth restore the balance and natural order. To a modern audience, there may be a feeling of regret that something more could perhaps have been done, and much sooner, to prevent such a tragic outcome.