On reading most definitions of “Paris Syndrome”, it’s easy to assume it’s an urban myth – and a xenophobic one at that. Defined generally as a kind of mental disorder which takes hold of tourists who visit Paris and are disappointed by what they see, it's also one which apparently afflicts Japanese people in particular: in 2006, the BBC reported that 12 Japanese people were struck down with it that summer, and in some this resulted in full “psychiatric breakdown”. In 2014, Bloomberg straightfacedly ran a piece noting that this “epidemic” was now affecting Chinese tourists, too. So what gives?

The roots of the syndrome, and our cultural obsession with it, seem to lie in the 19th century, when the author Marie-Henri Beyle (better known by his pen name Stendahl) claimed to be suffering from something called “Florence Syndrome”. He wrote of visiting the Basilica of Santa Croce:

I was in a sort of ecstasy, from the idea of being in Florence... Everything spoke so vividly to my soul. Ah, if I could only forget. I had palpitations of the heart, what in Berlin they call "nerves."

Florencian hospital staff still report incidents of tourists with elevated heartbeats and fast breathing after visiting various beautiful sites in the city.

This, however, is essentially the opposite of Paris syndrome, as it resulted from the wonder of the art and architecture in the city. The Japanese tourists who allegedly required psychological treatment after visiting Paris in 2006 were reported to be disappointed by the city, not impressed by it.

A news report at the time noted that the visitors came with a “deeply romantic vision “ of the capital, its culture and art, and the “beauty of French women”. Bloomberg claims that Chinese people arrive “expecting to see a quaint, affluent and friendly European city with smartly dressed men and women smelling of Chanel No. 5” after seeing films like Amelie or An American in Paris.

In reality, the thinking goes, the city’s “scruffy streets” and “unfriendly locals” are so shocking that visitors experience psychological problems as a result.

So do we – and Japanese people in particular – really have such an idealised vision of Paris? It was notable in the wake of the Paris attacks that much of the outpouring of sympathy and grief centred on a version of the city that would be virtually unrecognisable, or at least fairly meaningless to its residents – a "culture of baguettes and wine", the "city of love". It's idealised despite the fact that, in most ways, it's pretty much the same as other European capitals.

There's also a chance that "Paris Syndrome" is little more than "tourist syndrome". Culture shock is a recognised phenomenon, and it’s true that Japanese visitors may face more of a language and cultural barrier visitors from other European countries; they're also more likely to visit Paris than anywhere else in Europe. Many of the symptoms described by Stendahl and modern reports reflect those of heatstroke, or over-exertion – it’s easy to forget that walking around an unfamiliar city for a full day is much more draining than what we'd be doing at home.

Then there’s another possibility: the not-uncomon phenomena of inexplicable psychological reactions which repeat within a certain group, like the case of the fainting cheerleaders in the US. It’s impossible to know whether the 12 Japanese who needed treatment in 2006 knew one another – but it’s notable that similar statistics don't emerge every year, though there were reports of 20 cases of Paris syndrome in 2011.

Paris Syndrome, a 2014 novel by Tahir Shah, uses the phenomenon as its theme and title. In it, a character becomes obsessed with the French capital throughout her childhood and young adulthood. and finally goes there – only to be gripped by the syndrome, “rampage” through Louis Vuitton, and moon a sales clerk.

I haven’t read the novel in full, but it seems a clever satire on our interest in the phenomenon, as well as an exploration of the aspects of it that seem real. In one scene, a psychiatrist is asked on the news what causes Paris Syndrome:

“Obsession,” he said, mouthing the syllables thoughtfully. “An extreme obsession with Paris. An intoxicated sense of awe at its architecture, its customs, and its general jooie de vivre. Paris Syndrome is a manic inability to make sense of it all…. Paris Syndrome is among the most misunderstood and most dangerous of all psychological conditions.

Here, Paris syndrome seems to be the fixation and elevation of a thing until it can never really satisfy. The use of Paris seems basically incidental: tantrums among children on Christmas morning are an obvious parallel.

Perhaps it's simply a case of expecting a lot from a holiday, and reacting badly when it doesn't happen. Throw a long distance from home and an unfamiliar culture into the mix, and we have our explanation.