How should EMS handle something like this?
Last fall, when a dozen teenage girls in a single upstate New York high school developed a condition that looked like Tourette’s syndrome — complete with sudden verbal outbursts, uncontrollable arm motions and facial tics — it seemed likely that a chemical toxin or infectious agent was to blame. But none could be found.
Lights and sirens?
I have had calls like this. My handling has been a thorough assessment (usually in the presence of parents, because they often seem to be called before 911 is called), perhaps cardiac monitoring (depending on the assessment), and a nice calm transport of all patients to the same hospital (in case there is a connection in the origin of the symptoms – chemical exposure, drug ingestion, food poisoning, whatever).
How did things work out in the case being covered by the media? There is no mention of EMS response or treatment, so I don’t know.
doctors have already diagnosed most of the girls with a disorder: mass psychogenic illness — otherwise known as conversion disorder or, to use an outmoded term, mass hysteria.
We act surprised when our minds do not do what we trust them to do – tell us what is real. When our minds mislead us, we don’t believe it, but this is not uncommon.
Which line is longer?
This is the Müller-lyer Illusion. Measure the lines. Print them out if you need to. There is truth and then there is what our minds tell us.
Magicians use our constant distortion of reality to convince us that they are defying the laws of physics. Magic is just deception. Fortunately, most magicians will tell us that they are deceiving us, although they probably won’t tell us how they are deceiving us.
I saw it with my own eyes, so it must be true.
That is a lie. If a con man wants to find an easy mark, anybody who believes that is extremely gullible. The rest of us can be deceived too, but not as easily as someone who thinks that everything they see is real. The job is already mostly done. All the con man has to do is ask the believer for the money.
The medical version for treatments we believe in is –
I’ve seen it work! 
Hysteria is the most retrograde and non-womyn-empowering condition. It’s not supposed to happen anymore (we have Title IX!), but it won’t seem to go away. Both history and myth are filled with stories of girls exhibiting bizarre symptoms around the time of puberty — from Cassandra and her raving, to the girls of the Salem witch trials, to the girls whose households were believed to be the site of poltergeist hauntings, to cheerleaders in New York and North Carolina. Pubescent girls, it seems, are manifestly more likely to exhibit extreme and bizarre psychological symptoms than are teenage boys.
The condition may sound unlikely, but it is real, and it has in the past caused significant problems for emergency services.
To be continued in Part II.