Sydney had gone yarra over Americans and all things American.
Synonyms
insane, mentally ill, certifiable, deranged, demented, of unsound mind, out of one's mind, not in one's right mind, sick in the head, not together, crazy, crazed, lunatic, non compos mentis, unbalanced, unhinged, unstable, disturbed, distracted, stark mad, manic, frenzied, raving, distraught, frantic, hysterical, delirious, psychotic, psychopathic, mad as a hatter, mad as a march hare, away with the fairies, foaming at the mouth
Origin
1940s: from the name of a psychiatric hospital at Yarra Bend, Victoria.