Origin of worrywartworry + wart
Attested 1956, I. BELKNAP Human Problems of State Mental Hospitals x. 177 In cartoon Out Our Way by J. R. Williams, there is a character by that name. Earlier examples from newspapers of the 1930s and 1940s.
Presumably related to earlier worryguts.
From worry; “wart" apparently chosen for alliteration.