The "false memory" thing started as a =legal defense=, not a psychological or medical diagnosis. As I recall, it came to prominence during the George Franklin case (1990-91) in California, where a man was convicted of murdering his daughter's playmate based entirely on his daughter's 20-year-old "recovered memories" with absolutely NO other evidence. I have to admit, if I were a juror, I would have "reasonable doubt" of his guilt, in the absence of any other evidence linking the defendant to this crime. Franklin was convicted but this was later reversed for violation of his right to avoid self-incrimination. The reversal had nothing to do with the "false memory" issue--rather, it was because the prosecutor had presented as evidence Franklin's refusal to answer his daughter's question about the death when she confronted him in the prison visiting room. He had simply made a "shush" gesture and pointed to the surveillance camera.
Since then the "false memory defense" has been used to discredit and disparage many delayed-recall witnesses, both credible and in-, corroborated and un-. There's no doubt that our memory can be erroneous, at least as to details, and that other people can influence what we believe we remember. However, the "false memory" argument carefully avoids the subject of traumatic amnesia, which ranges from forgetting one's lines due to stage fright, all the way to "missing time" in the course of extreme trauma.
I'm not a doctor and I don't play one on the Internet, but I've had to learn about this stuff in order to hang onto sanity over the past 18 years. Peace, all!