4 ideas
Berlin psychiatrist Viktor Larenz's twelve-year-old daughter Josy, chronically ill with symptoms no doctor can explain, disappears without a trace from an allergist's waiting room. Years later, withdrawn to the North Sea island of Parkum, he is visited by Anna Spiegel, a writer who says her fictional characters come to life; her novel-in-progress about a sick girl who vanishes mirrors Josy's case in details only he could know.
A delusional mind can externalize knowledge it cannot bear to own by projecting it onto an invented other who then 'reveals' it back. The self can then encounter its guilt as a stranger's story, investigating it with curiosity instead of acknowledging it as memory. The visitor's surname, Spiegel ('mirror'), encodes this: the stranger who knows too much is the protagonist.
When a child's chronic symptoms defy every diagnosis, one possibility is that the illness is being produced by the caretaker who seems most devoted to curing it. Munchausen syndrome by proxy hides inside the role society trusts most, the anxious parent seeking specialists, so the search for an outside cause becomes the disguise.
A psychiatrist's professional knowledge of delusion and denial gives him no immunity to them; he can apply clinical reasoning skillfully to everyone except himself. Expert fluency can make self-deception more convincing, because the expert supplies coherent, clinically plausible explanations that shield the core falsehood.