About 20 years ago, my late Mam (a Dubliner) was shopping with my brother's US (2nd) wife - he's on his third now!! lol I'm quite happy".
Anyway Valerie was admiring something that my mother thought was horrible and grossly overpriced. She said to her "Are you mad?" Valerie responded"No, I'm not mad
In US mad is interpreted as being angry.
Similarly I was at the Oktoberfest in 87, and I was chatting to some Aussies and Kiwis at Thalkirchen campsite, where I was staying, and i said 'was really pi*sed last night to which they all replied 'oh. what happened to upset you mate?"
For antipodeans, it means angry or fed up. For me it was the explanation for my hangover.