You see though, gaslighting is tricky.
It's become more trendy to accuse people of doing it... when instead potentially the one yelling it is actually being delusional. Like, what do you even do to convince someone of a temporarily and radically aberrant world view that what they're saying or thinking isn't sensible these days? Telling friends about it has a way of typically just being enabled and back pat by said friends instead of getting any truly unbiased data, typically leading to more self-driven skew that is independent of the need for truth.
That aside the 1944 movie is great:
Ę̵̚x̸͎̾i̴͚̽s̵̻͐t̷͐ͅe̷̯͠n̴̤̚t̵̻̅i̵͉̿a̴̮͊l̵͍̂ ̴̹̕D̵̤̀e̸͓͂t̵̢͂e̴͕̓c̸̗̄t̴̗̿ï̶̪v̷̲̍é̵͔