Yes, you have "been looking through some (!) past cases", but apparently not enough, and there's probably a reason why you seem to prefer the medieval ones when no properly medically trained observer was present...
They did not have cartoons in Japan in medieval times; that reference was to a case from 1997. The fainting schoolgirls reference was to a case from Sri Lanka in 2012. The laughing epidemic comes to us from 1962. In fact of all the cases I made a reference to only a single one was from "medieval" times, which was the "dancing mania".
It simply isn't true - at least it isn't true of contemporary cases: sick building syndrome, complaints about electro smog or the recent, and to some extent still ongoing HPV-vaccine scare in my own country.
Most of these are simple personal delusions, not cases of mass hysteria. "Windmill sickness", "WiFi sensitivity", "Morgellon's disease", and being a "targeted individual" are similar instances. Yes, in the internet age individuals who have these delusions are able to find each other, communicate, and reinforce each other's delusions; but two people who live downwind from a wind turbine but a mile away from each other getting "sick", and finding a website where they can talk to isolated "sick" people downwind from wind turbines in completely different regions and countries does not make a case of "mass hysteria". Likewise, a person living near a cell tower who gets sick, and only later finds out about cell towers "making people sick" and becomes convinced that's what happened to him, is not a victim of "mass hysteria"; he's just
wrong.
As for "sick building syndrome" - again, "mass hysteria" is a reach. When minor illnesses with simple symptoms are a dependable occurrence, and nearly everyone works in buildings where many other people work, and a good number of people live in multi-family dwellings, it is a statistical inevitability that there will be workplaces and apartment buildings where there is what looks like an unusually high number of inhabitants with a variety of illnesses at the same time.
So now you're blaming me that what I guess will happen "in the near future" hasn't already happened???!
The point was, we are already in the "near future" relative to the months-old events in the article you're referencing. At what point do we stop being in the "near future" of those events? A year afterward? Can't be too many cases of
mass hysteria where some random tourist succumbs to the "mystery illness" 8 months later.
If all you're saying is that sometimes people may develop memory loss, then I'll have to agree with you. People do that all the time and for various reasons. But the kind of memory loss described here is pretty specific, and the reason why I mentioned my own experience with very similar 'symptoms' was that I seriously doubt that we're talking about anything other than people in a prolonged state of anxiety beginning to question and worry about every little thing that they imagine might be wrong with them and a symptom of a serious defect - much like the tourist staying at the Hotel Capri who appears to have come down with a bad case of hypochondria based only on the tingling sensations that he felt in his extremities when he started relaxing after a long day of walking in Havana.
The "kind" of memory loss here meaning, "inability to recall certain words", as related by the article I presume? This isn't very specific at all; it could just as easily refer to a diminishing score on a CAS assessment during a checkup, rather than a victim running in a mortal panic to his doctor because there's been a word right on the tip of his tongue all day and he
just knows That Cuba Thing must've made him unable to recall it.
That is the problem with the diagnosis of mass hysteria/mass psychogenic illness that you seem to be unable to grasp: In modern medicine it has become fairly easy to find evidence for most diseases: you x-ray the led and find the fracture, you analyze the blood and discover the virus or the antibodies corresponding to a well-defined disease. That is proof positive. What's funny about the diagnosis of a psychogenic illness is that you do much the same thing, and when you don't find anything, you begin to suspect hypochondria or - if you have a number of patients from the same group: mass psychogenic illness. That is the 'proof', i.e. the absence of proof of something else, an actual disease - but, of course, proof is not what you're looking for ...
But that's not always true, though. Of course things like fractures have simple explanations. Many diseases have defining and singular characteristics that allow them to be diagnosed as easily as a broken bone, or tests that are highly accurate at indicating the presence of a specific pathogen. Other symptoms like headaches and nausea are far less definitive or useful for diagnosis. They are actually caused by real diseases - AND can also be caused by stress, or environmental factors, or nothing at all. And without something specific to look for, it's very difficult to perform tests; hospitals generally cannot take a vial of blood and literally screen it for an all-encompassing list of every single chemical and pathogen it contains which can then be scrutinized to root out the culprit whatever it may be. For the most part, doctors must look at the totality of symptoms and hope that somewhere among them is a telltale, or at least something suggestive of an actual, more specific, practical and likely path to diagnosis - something that tells them which of the myriad more-narrow and -practical tests available to them is most likely to give a useful result. If they can't find such a helpful symptom or symptoms, they do
not immediately leap to "hypochondriac" or "mass hysteria". The symptoms are typically just considered idiopathic and the course of treatment then becomes to simply treat the symptoms.
No, it isn't! If you get diarrhea (and I've had the 'pleasure' more than once in Cuba), it's fairly easy to diagnose what causes it: You just have to look for the "micro-critters" in a stool sample. Critters found - diagnosis complete: That is what actually caused the symptoms, and it's usually relatively easy to cure. (And if not: drink plenty of water and wait it out.)
That's convenient in the case of diarrhea specifically; but here you've taken one symptom of from a list I've given, and one cause from a list I've given, and while you've earned congratulations for managing to square those specific items with each other, we can't act like that throws the entire point out the window. Diarrhea, among symptoms, and local infectious bacteria, among causes, happen to be particularly easy to diagnose just as you describe. The headaches and nausea, and environmental causes, do not so easy lend themselves to simple tests as I explained above.
Wondering, investigating and inquiring are very admirable endeavors, but now you're trying to change the paradigm, to turn it into a case of semi-skeptics coming down with something on a sea cruise, which is obviously not what happened here.
I don't see where "semi-skeptics" is important to the scenario; a ship of outstanding fools can just as easily each come down with something around the same time and wonder if there's a connection with no less credibility. But essentially, I disagree - I think the idea of a bunch of people "coming down with something on a sea cruise" is a rather excellent metaphor for what has happened in this case.