"Well it could have been amnesia!"

Somebody said this in a movie. It's a movie I know very well. It was a woman, speaking angrily, in response to a question about something she said she saw, but then turned out there was no evidence for. Maybe it was Sigourney Weaver in Ghostbusters? I don't think that's right though. I can hear the voice and I can almost see the face as this line is being delivered. But I can't think of any other points of reference that would tell me what movie this is from.

If I think of it, I'll leave a comment. Gah, this is so frustrating.