De Clerambault's Syndrome, also called erotomania, is a psychological condition in which the sufferer is under the delusion that a certain person is in love with him or her. Typically, the object of this delusion is of a higher social class than the sufferer and is merely an acquaintance — at the most — in reality. To the person with the condition, everything that the object of affection does takes on a special significance that it does not really have. It is named after Gaetan Gatian de Clerambault, a French psychiatrist who wrote a comprehensive paper on the condition in 1921.
This condition has been recognized in some form since long before Gaetan Gatian de Clerambault published his paper, although there was no standard term for it. Ancient authors, including Hippocrates and Plutarch, describe cases that today would probably be diagnosed as de Clerambault's syndrome. Psychiatrist Jacques Ferrand is credited with the first mention of the syndrome in psychiatric literature in 1623. The concept has changed throughout the centuries, as it was originally likened to illness caused by unrequited love, and only relatively recently came to be understood as a delusional belief that another person is making romantic advances.
There have been many famous cases of de Clerambault's syndrome, most of which manifested themselves through stalking behavior. The object of many of these cases was a celebrity of some sort, either in the realm of politics or entertainment. One of the most well-known cases affected John Hinckley, Jr., who shot President Ronald Reagan in 1981 in an attempt to impress actress Jodie Foster, who he believed wanted a sign of his devotion.
De Clerambault's syndrome has also often been the subject of fiction. Nikolai Gogol's classic story, "Diary of a Madman" (1835), describes a descent into insanity that begins with a case of this condition. Ian McEwan's novel Enduring Love (1997), adapted to film in 2004, tells the story of a homosexual case of the condition. The syndrome is also the subject of the 2002 French film He Loves Me... He Loves Me Not, starring Audrey Tautou of Amelie fame.