It's well known that to gaslight someone is to cause them to question their own perception of reality, from the 1940s movie Gas Light.
I came across the usage gaslit to refer to someone so treated, but this sounds off. Gaslit is certainly the adjective to use when describing something actually lit by a gas light, but it seems that when invoking the movie we should say that someone has been gaslighted, since gaslighting is a separate term not involving actual light.
Unfortunately I can't find any authority either way. The instances of gaslit I've found clearly refer to physical lights. Can I get either an authority or a strong opinion? (-: