30/9/19 Mad v. crazy
The meanings of these words are different between American and British English. In the UK, “mad” and “crazy” are basically the same, both words indicate a state of mental instability. (However, neither term would be used by professionals to describe mental illness.) In the US, although “mad” and “crazy” are also colloquially used to refer to someone insane, the difference is that the primary sense of “mad” is “angry” or “upset.” So when the phrase Are you mad? is used inquisitively, it means the asker wants to know if the person is upset.