I don't know but Google Trends [1][2] bears out that it's very recently common. My best guess is that it has come up as part of the Amber Heard / Johnny Depp t

I don't know but Google Trends [1][2] bears out that it's very recently common. My best guess is that it has come up as part of the Amber Heard / Johnny Depp trial and that has spurred a lot of people searching for it. [1] Past 5 years, March & earlier - https://trends.google.com/trends/explore?date=2017-03-01%202022-03-01&geo=US&q=gaslit https://trends.google.com/trends/explore?date=2017-03-01%202... [2] Past 90 days including giant spike - https://trends.google.com/trends/explore?date=today%203-m&geo=US&q=gaslit https://trends.google.com/trends/explore?date=today%203-m&ge... (if you go to past year you can see the spike)