PSYCHOLOGY – Now called “mass psychogenic disorders,” these epidemics of the mind cause the same symptoms in dozens of people with no identifiable cause.
An entire group of college students seized with inexplicable headaches and nausea. Nuns who mew at fixed times in a Parisian convent. A giggle which, for months, is transmitted between girls in Tanzania. So many examples of an astonishing and poorly understood phenomenon once called “mass hysteria”. Rare episodes, but striking, because, in the absence of an identified organic cause, all the hypotheses can be evoked, including the conspiracy. But how to understand these “epidemics of the mind”?
The “dancing plague” epidemic in Strasbourg in 1518 is one of the first well-documented cases of what is now called “mass psychogenic disorders” (MPD): hundreds of people, especially women, begin to dance uncontrollably, until exhaustion and sometimes death. The phenomenon, which lasts several weeks, is widely discussed throughout Europe, and the authorities finally refute a supernatural origin to agree…