De Clérambault's syndrome, the central disorder in Enduring Love, was first comprehensively diagnosed by a French psychiatrist named Gaetan Gatian de Clérambault. Although another name for it is erotomania, it should not be confused with "obsessive love", unrequited love, or hypersexuality. Erotomania is a type of paranoid delusion where the patient believes that a social superior is in love with them. Sufferers are often isolated and unemployed individuals who are in mid-to-late adulthood. The object of the obsession is usually older, of a higher social status, and either a visible or celibate figure i.e. a politician or a priest. There is almost never previous contact between the patient and the victim, and definitely no encouragement from the victim.
De Clérambault's syndrome sufferers are unaware of the psychiatric nature of their love, and therefore do not seek treatment. They often believe that the object of their obsession is more in love with them than vice versa, and they take great pride in the fact, interpreting the victim's embarrassment as a sign of their love. If erotomania persists, the patient may start stalking or threatening the victim, and will occasionally grow violent. Erotomania is linked to other psychiatric illnesses, including paranoid schizophrenia, schizo-affective disorder, major depression, bipolar disorder, or Alzheimer's disease.
Erotomania is very rare and difficult to diagnose or define. Because of this, many psychiatrists instead view it as a construct reflecting Western views of love, both spiritual and physical. It is nearly impossible to localize within the brain, and it will be difficult to ever find an effective biological treatment.