A reader emailed me about an outbreak of "disease" at a girl's boarding school in Mexico:

In November, a mysterious illness began to affect girls at a boarding school in Chalco, Mexico, near Mexico City. The school, which is run by Roman Catholic nuns, is one of 10 in Asia and Latin America operated by a charity called World Villages for Children in Asia. The girls, ages 12 to 17, showed strange symptoms: difficulty walking, fever and nausea. After the girls returned from a 10-day Christmas break, the illness spread. Eventually 600 out of the 3,600 girls at the school showed symptoms. Still, no one could figure out what was making the girls sick, and public health officials were called in.

After conducting numerous tests, surveying the facilities and interviewing some of the afflicted girls, doctors have decided that a psychological disorder is responsible. Its official name is mass psychogenic disorder, also called collective hysteria, mass psychosomatic reaction or mass hysteria.

Mass psychogenic disorder is a rare -- but not unheard of -- phenomenon. The disorder is usually characterized by the mysterious spread of a variety of symptoms without a discernible cause. It frequently occurs in closed, insulated communities, such as schools and factories, and among teenagers and girls. Collective hysteria can spread when a fear exists of exposure to a disease, combined with a contained, stressful environment.

Such diseases, even though they are in the mind, are nonetheless transmitted in a collective manner -- via association, and the "nocebo effect":

Mass psychogenic disorder is a phenomenon that can be understood as resulting, in part, from the nocebo effect. Think of the nocebo effect as the opposite of the placebo effect. Instead of good thoughts or associations producing a positive outcome, bad thoughts and associations produce bad results. For example, in the early 1990s, a study showed that women who believed they were prone to heart disease were four times more likely to die than women who didn't believe they were susceptible, even though both groups of women had similar risk factors [Source: Washington Post]. The study showed that when people feel that they have been exposed to a contaminant or a disease -- or that they are predisposed to becoming sick -- they are more likely to develop symptoms.

What about people who have multiple sensitivities to innumerable but undetermined toxins? The article continues:

In a truly bizarre case, a story emerged last month in London, in which a woman revealed she's "allergic to modern living" [AllHeadline News]. Debbie Bird claims that she's allergic to electromagnetic fields (EMF) from computers, microwaves, and cellular phones. EMF fields, Bird claims, give her skin rashes and make her eyelids swell. She has made her house an EMF-free zone with carbon paint on the walls and covered her windows with protective films. She and her husband even sleep under a silver-plated mosquito net to keep out radio waves.

Debbie Bird's not the only one of her kind. Many other people suffer from mysterious ailments where they experience genuine symptoms without any discernible cause. These afflictions include multiple chemical sensitivity -- an allergy to many types of common chemicals -- and "sick building syndrome," in which people become sick from time spent in a building (frequently an office) without any apparent cause.

Years ago I read John Sarno's "The Mindbody Prescription," and I see he has a new book titled "The Epidemic of Mindbody Disorders." Dr. Sarno noticed that, for example, people who hated their jobs were more likely to develop "work related" tendonitis, but once they switched to another work place the tendonitis would get better even if the work was the same. There's an interview with Sarno here, and a grateful patient has set up this website testimonial. (And, of course a Wiki entry mentioning how Sarno cured Howard Stern, which is where I heard about the guy.)

Interestingly, hearing Howard Stern talk about Dr. Sarno helped change my thinking about psychogenic illness, and what fascinated me the most was learning that some people get dramatically better once they understand the mind-body connection. Others become infuriated, and reject out of hand the possibility that there isn't a "real" cause for their suffering. I don't know where people get the idea that because something is in your mind, that it isn't "real," but that's the way people are.

Because I'm online so much and I see so many potential sources of hysteria, what concerns me is the possibility of (dare I say it) online infection. Laugh if you will, but what is in our brain consists of information, and if we move from the individual with tendonitis to people who are in groups or who have formed groups, I think it begs the question that outbreaks of online mass psychogenic illness might become a real possibility -- assuming they haven't happened already.

An article in Psychiatric Times elaborates on Mass Psychogenic Illness (aka MPI). After discussing a typical outbreak and noting that the disease is more common than most people realize, Dr. Timothy Jones notes its characteristics:

Overview of MPI

MPI has been characterized as a constellation of symptoms suggestive of organic disease that lacks an identified cause, which occurs among people who share beliefs regarding those symptoms (Philen et al., 1989). It is seen as a social phenomenon, affecting otherwise healthy individuals (Boss, 1997). While ruling out other potential causes of an outbreak is critical, MPI is not simply a diagnosis of exclusion. MPI has no pathognomonic features, but a variety of characteristics should prompt its consideration and can support the diagnosis.

Recognizing the Diagnosis

Outbreaks of MPI are often triggered by an environmental event (Boss, 1997). Odors are a common trigger, although reports of contamination of water or food (Anonymous, 1999; Cartter et al., 1989; David and Wessely, 1995), smog (Araki and Honma, 1986), and numerous other environmental events have been associated with such incidents. Outbreaks are often enhanced by a vigorous emergency response and substantial media attention (Hefez, 1985; Philen et al., 1989). Symptoms may spread almost instantaneously and by line of sight, the latter term referring to the apparent spread of outbreak among those who directly observe other affected people.

Children and adolescents are frequently affected (Boss, 1997), and the phenomenon commonly involves groups under stress (Philen et al., 1989). Females are often disproportionately affected (Boss, 1997). The symptoms reported in such outbreaks may be inconsistent with a single toxic or infectious etiology. Typically, no objective evidence of organic disease is detected on medical evaluation. Hyperventilation and associated symptoms are common, as are headache, nausea and vomiting, dizziness, abdominal distress, weakness, and respiratory symptoms. Several outbreaks have been described involving rashes (Robinson et al., 1984; Rouechý, 1991). Symptoms generally resolve with removal of those affected from the scene, observation and reassurance.

In a review of the medical literature pertaining to both MPI and outbreaks of confirmed toxic exposures, I was unable to identify any outbreaks of acute illness from toxic exposures, with minimal physical findings, where the cause was not quickly apparent to investigators. Mass psychogenic illness should be considered in the differential diagnosis of clusters of illness with no objective signs of disease, the cause of which cannot be identified quickly.

a group of people claiming to be suffering a variety of symptoms they attribute to the mercury fillings in their teeth despite the lack of any evidence of mercury toxicity related to dental fillings

a mysterious illlness called "Morgellons Disease" with all kinds of symptoms which the CDC refused to recognize, but which sufferers indignantly claimed they have (just read the comments).

QUESTION: Can we really be sure that Morgellons Disease might not be caused by Global Warming?

Who is in charge of whose denial?

EnviroSpin Watch has discussed cycles of Global Warming related manic depression, while Pardon My English notes the well-documented phenomenon of children's Global Warming nightmares.

Add to this the increasing kneejerk tendency to automatically blame human activity for unusual natural phenomena (a good example is Colony Collapse Disorder in honeybees being blamed on cell phones despite a lack of correlation). Factor in the persecution sensitivities which often drive identity politics awareness -- examples can be found in studies showing racism (or the perception thereof) makes people physically sick, thus triggering the need for support groups. Is it unreasonable to expect that people who imagine Global Warming has made them physically sick might form "support groups"?

Considering the documented existence of MPI, might such support groups actually aggravate -- or even help generate -- the very illnesses they claim to "support"? For that matter, what constitutes "support"?

There certainly wouldn't be any denying the reality of symptoms. Certainly, I would not deny that someone feels the way he feels. But don't I have the right to deny personal responsibility? Am I in any way responsible for the feelings of people I do not know? Or might there be such a thing as a collective illness suffered by one group because it was collectively "caused" by another?

This is more complicated than it seems, because (at the risk of sounding like a heartless and mean spirited pig) I actually think sick people need help.

I mean, it's not as if illness is anything to be ashamed of, right?

Ah, but the catch is that disorders connected to the mind are typically associated with shame in a way that physical disorders are not.

Don't blame me. I didn't make the rules.

UPDATE: Commenter Metapundit is assuming I've read Neal Stephenson's "Snow Crash," which according to him,

explores some of these ideas - the novel is cyberpunk with action taking place in meatspace and cyberspace. Interesting though is the idea of viruses (audio/visual) which hack the software we have running on our hardware (the brain).

There's no way to prove I didn't read something, though, and if this went to trial I would probably call Justin to bear witness to my ignorance. He knows my reading habits, and while he can't swear under penalty of perjury that I never read something, I think he would readily confirm that it's highly unlikely I ever read "Snow Crash."

(So I plead ignorant, although it's nothing to be proud of.)