I don’t claim any degree in psychology but from my life experiences....I’d say Jackie is a two-star nutcase. Just nutty enough that I wouldn’t hang around her or share a cup or coffee with her. She’s not nuts enough to put into some mental facility or lock up....but she’s just nutty enough to make your life miserable with some fabricated story, then admit it was fake five years later.
I have a sister who has some issues, so I know what you mean. Sometimes she’s just fine, but others, she can go off on the deep end. She is medicated most of the time, and that does seem to help, but when she “forgets”, it’s a roller coaster ride from hell.
I think that Jackie is another step nuttier than my sister. That she created this fictional date from some guy who went to her high school is really bizarre behavior. I hope her parents are strong enough to see through her ruse now, and get her good professional help.