 If someone calls you Barking Mad, it means they think you're crazy. And a lot of people think this is related to a crazy dog barking. Whilst its origins are disputed, the likely origins actually lie in the East London town of Barking. In medieval times, Barking was home to a lunatic asylum, which was notorious for its deranged inhabitants. It wasn't long before the expression Barking Mad was used throughout England to refer to someone who was crazy.