Josh Hartnett's suave insouciance in Lucky Number Slevin (2006) is accounted for by him "having ataraxia." [1] That is, as if it were a medical condition. I'm sure it was intended as a joke, but apparently wiktionary says "ataraxy" is sometimes used in a similar way, although I've never seen that. [2]
[1] https://www.youtube.com/watch?v=vjDTmTAy5rs
[2] https://en.wiktionary.org/wiki/ataraxy#English