Is Macbeth Mad?

In Shakespeare's play, "Macbeth," the protagonist and the play's namesake, Macbeth, may appear crazy at first, but this is not actually so. The question is first raised during the famous scene where Macbeth sees a dagger, yet cannot touch it, as he says, "I have thee not, and yet I see thee still." (2.1.35). This dagger is clearly a hallucination that Macbeth is having. He continues to question whether he can believe what he sees or not, but eventually concludes upon it being an illusion where he states, "There's no such thing:/ It is the bloody business which informs/ Thus to mine eyes." (2.1.47-49). These lines are especially important, because it shows that he has decided that he is seeing this hallucination due to murder being on his mind. This murder however, is not an uncontrollable urge of a lunatic; it is a planned assassination, aimed towards a specific goal.  The reason Macbeth saw the hallucination wasn't because he was schizophrenic, but rather that he was very stressed and had been focusing too hard on a certain topic. The fact that he can still tell the difference between his delusions and reality speaks heavily in his favor for being sane.