ding-dong, adj.³ — Green’s Dictionary of Slang

ding-dong adj.³

[ding-dong n.⁴; the supposed ringing bells heard by the sufferer]

eccentric, insane.

1963		J. Blake letter 8 Sept. in Joint (1972) 222: This ticktock, dingdong, jargon-hung, gimmick-headed little fat rotten egg.
2005		J. Stahl I, Fatty 202: The prune-juice-and-paint-thinner left me fairly ding-dong.