Less well known is the Helsinki syndrome, usually referred to when mistakenly meaning Stockholm syndrome, such as in the movie Die Hard, for example, and by Richard Hammond on Top Gear, but it actually originates from the Helsinki Accord of 1975, which attempted to thaw relations between the communist bloc and the west. It was non-binding. The syndrome alludes to a psychological lack of attention, for example if you'd run over a deer in your car but blocked out all memory of it (as it was too upsetting).
Other cities with syndromes sound like they're just getting on the city syndrome bandwagon: Lima syndrome, coined in 1996, is the opposite of Stockholm, so it's where the criminals feel sympathy for their hostages. Oslo syndrome posited the theory that Stockholm syndrome can be applied to an entire people – in the case of Kenneth Levin's 2005 book, The Oslo Syndrome: Delusions of a People Under Siege, it's the Arab-Israel conflict.
By the time we get to the Paris syndrome, things are getting odd: it's a delusional state which can occur whilst visiting the city. Affecting mainly Japanese tourists, it's apparently an extreme form of culture shock and is blamed on Japanese magazines which feature idealised images of Paris. Florence syndrome, or Stendhal's syndrome, is a similar occurrence, which can produce fainting and confusion when exposed to beauty and art, such as is found in the Italian city. Jerusalem syndrome involves psychotic decompensation when visiting the city.
Paris, Florence and Jerusalem are the only three syndromes that pertain to being in the actual city (and all involve the difference between the city of the imagination, and being unable to cope with the actual reality of the place); with the others it doesn't matter. For example, you can suffer from Oslo syndrome in Jakarta and Stockholm syndrome in London, as long as you get kidnapped, of course.
In the news recently: there was a China syndrome of sorts the other day when the Chinese stock market suffered heavy losses. The term actually refers to a nuclear meltdown, from the somewhat outdated notion that the meltdown would go far down to the other side of the world (apparently, China). Also a fine 1979 thriller starring Jack Lemmon, Michael Douglas and Jane Fonda.