Are you mad? Are you nuts? Are you crazy? Are you out of your mind? Are you a lunatic? No, we never use the last statement! We do not call people lunatics. Being a lunatic is a serious matter. It is not being crazy or nuts or scattered brain or anything we may call each other casually. However a lunatic is someone who needs to confine to a sanatorium, or just to pay a visit to a psychiatrist. In such a case, we do not still call the person a lunatic, but call the doctor or the hospital.