Demoted Memories

Alice used to be something great, or at least be a part of something great. For example a queen or a wizard, or a friend of either. She still remembers it, but she no longer believes in it. Instead she has demoted her memories to the role of something lesser. She keeps telling herself that it was All Just a Dream, Fake Memories, insanity, overactive imagination, whatever...

Note that the greatness doesn't have to be a good thing so she might have good reason to pretend it never really happened.

In either case, her past is likely to catch up with her one day...

Sometimes a kind of retroactive Weirdness Censor from an Agent Scully who actually does know better but just won't admit it to herself. Maybe because a deep wish for Brain Bleach has turned her into a Consummate Liar. In either case, heavy doses of Doublethink may be applied.

This is frequently a side effect of Amnesiac Dissonance.

Comic Books

 * In Starborn, the hero initially believes himself to have invented an entire Sci-Fi setting. However, it's actually his real background. He knew that as a kid, but his earthly foster father talked him out of believing such nonsense.

Film

 * This ended up being the one of the main plot devices in The Final Cut. The film opens with Alan's memory of him causing Louis to fall to his death when they were both kids, but when going through the memories of Charles Bannister, he finds a man who looks like Louis. Cue Alan's frantic search for the truth about his memories.
 * Happens in Hook: Peter Pan grew up in the real world and refuses to believe that he used to be Peter Pan, even when Captain Hook leaves him a note.
 * Late in the film Twelve Monkeys, Cole starts to believe he really is just an escaped schizophrenic and not a time-traveler.

Literature

 * The Philip K Dick story "We Can Remember It For You Wholesale" (heavily changed for the movie adaptation Total Recall.) The protagonist's vivid fantasies of being a secret agent on Mars lead him to request that Fake Memories of same be implanted by a company that does this as a sort of virtual vacation. Except that the fantasy turns out to have been actual memories due to an incomplete mind wipe.
 * This seems to be happening to Kinbote at various points in Pale Fire, though it really picks up near the end.
 * In The Chronicles of Narnia, Susan gradually develops a refusal to believe in her own life. In the last book, she refuses to believe that any of her adventures ever happened. This saves her life, which is not a good thing in this kind of setting: she's left behind on Earth while everyone else go to heaven to be Pals With Aslan. Her disbelief is a very drastic step, considering she spent at least a decade as queen of Narnia. After leaving Earth the first time, she practically grew up in Narnia. While an immigrant, it is her home as much as England is. So, why does she disbelieve her memories? Well, there are two ways to interpret the situation:
 * The narrative solution: The Last Battle is very much an Author Tract against Muslims, Hindus, Atheists, new religious movements, and former Christians who left the faith. Each of these camps has its own set of Straw Loser characters, and Susan gets to fill this role for the "former Christian" category. This impression is reinforced by how no other characters try to understand her. Instead, they simply dismiss her as a shallow idiot who has taken a Face Bimbo Turn.
 * The Psychological solution, considering the Fridge Horror of the series: for a character in Susan's position, it's quite realistic to be so emotionally traumatized that she tries to flee from her memories and pretend none of it ever happened. In the second book, she and her siblings got dropped into another world and drafted to be Child Soldiers. After surviving the war she became queen, spending the rest of her youth as royalty of her new home country. Then as an adult, she's suddenly cast out of her new home and reverted to childhood. When she get sucked into Narnia again (quite painfully, and as always without her consent), it is a land ravaged by brutal oppression. She is again forced to become a Child Soldier, suffering through the horrors of war. When the dust has finally settled and she has done her part, she is again cast out - and this time informed that she will never be allowed to come home again.
 * In Harry Potter, Aunt Petunia is portrayed as this trope.
 * The Pat Cadigan short story "This is Your Life (Repressed Memory Remix)" involves a therapist trying to convince a woman that her happy childhood memories are a cover for Repressed Memories of her father sexually abusing her. The ruse has already worked on her brother.

Live Action TV

 * In Buffy the Vampire Slayer, this is the fate the demon of the episode "Normal Again" had in store for Buffy: she would be tricked into killing all her friends and then spend the rest of her life telling herself that they never existed and that she was never the slayer. That all her memories of Sunnydale was made up in her own head while she was a psychotic living in a mental institution.
 * Variant: Toward the end of Dollhouse, seems to prefer retaining  composite identity to the possibility of regaining the memories of  despite that being the original memory and personality set.
 * Done more directly with 's shocking discovery that is actually a "doll" with altered memories.
 * This turns up in Doctor Who series 3, when the Chameleon Arch makes the Doctor and human with a false identity.

Tabletop Games

 * In KULT, this is a core part of several recommended character backgrounds. The character starts out as a normal human with a denied supernatural or at least abnormal background.

Video Games

 * This starts to crop up a lot as the plot of the old NES game Vice: Project Doom progresses.