The human mind is indeed a strange thing and thereby it is not unusual to think that they have some strange disorders. While this may amuse the people who read about this, the people who are going through it really do suffer. But luckily these strange disorders are not that common and very few people undergo through them.
Here is the list:
Stockholm Syndrome : It is a kind of mental stage when the person who has been kidnapped starts to feel sympathy and understanding for the kidnappers. What happens with people undergoing the Stockholm Syndrome is that the hostage sees every act of the kidnapper in a positive light and go so far as to defend them when the kidnappers are caught. This syndrome got its name when during the robbery of Kreditbanken in Stockholm, on 23rd Aug to 28th Aug 1973, the bank employees started to feel a bond with the captors. Another syndrome called the Lima Syndrome is also there when the abductors start liking the hostages. This name was coined after an abduction in Lima at the Japanese Embassy in the year 1996 where the hostages were freed very soon after the kidnapping.
Capgras delusion theory: Under this disorder the person falsely believes that someone close to them is not the same and is actually an impostor who happens to look identical. The name for this came from the Joseph Capgras the psychriatist of French origin talked about this for the first time in the year 1929. The paper was written along with Reboul Lachaux and was about a French woman had claimed that her husband and others in her life had been replaced by doubles who looked identical.
The Fregoli Delusion or the delusion of doubles: This one is in fact on the opposite end of the spectrum, where the person having this delusion believes that the same person keeps coming to him or her in different forms after altering their appearance. The name comes from Leopoldo Fergoli who is well known for his ability to change appearances very quickly during his stage performances.
Alice-in-Wonderland syndrome or Todd’s syndrome: In this case the human perception gets affected and could be the result of brain tumors, migraine or due to taking psychoactive drugs. The person who is undergoing this may feel that part of their body has been transformed in size or appearance or even view other beings as smaller in size than they are.
Celebriphilia: This is actually a really virulent desire to form a love or romantic bond with a celebrity. This definitely does not include those harmless romantic fantasies you have as a teenager.
Alien hand syndrome or Dr. Strangelove syndrome: This is a neurological problem when the person affected finds that his or her hand acts on its own like using tools and undoing things etc. It happens due to strokes, infections, some cases of epilepsy and due to brain surgery.
Hybristophilia: This syndrome involves being extremely turned on a by a person who has committed horrible crimes.
Münchausen syndrome or hospital addiction syndrome: This has people feigning illness in a bid to get attention. The idea is get sympathy from people due to health conditions. Named after the Baron Munchhausen who made up stories that were impossible to believe about himself.
Koro or genital retraction syndrome or shrinking penis: This is a syndrome that is culture specific being from the southeast part of Asia where the person starts believing that his genitals are shrinking and will soon disappear. Among women it could be based on nipples retraction or shrinking to nothingness.
Pica: Under this syndrome the person suffering it starts believing that things that are not eaten like buttons, hair etc are edible leading to serious problems. This has been linked to deficiencies in the body, mental disability or even chemical imbalance.