Mass psychogenic illness is a condition that is usually induced by stress, fear, or emotional distress. It can be caused by reports of things such as exposure to chemicals, toxins, or viruses, and the symptoms that result are so real that it’s hard to believe they don’t have a biological source. Mass psychogenic illness spreads primarily because of humans’ unconscious, involuntary social mimicry of one another’s behavior.
When looking at specific cases of mass psychogenic illness, you might think that they are so absurd they must be made up. But sometimes, real life can be stranger than fiction. Here are some of the craziest cases of this phenomenon throughout history.
The Dancing Plague of 1518
During the summer of 1518 in France, a large number of people spontaneously began dancing. This behavior lasted for weeks, and the people “infected” were unable to rest for over a month. As a result, many of the people ended up dying due to stroke, exhaustion, and heart attacks. Within just one month, this dancing plague spread from one woman to over 400 people, and to this day the cause of this mass psychogenic illness remains unknown.
The Laughter Epidemic of 1962
In a small Tanzanian village in 1962, an innocent joke within a boarding school led to a laughing epidemic that lasted for over 18 months and infected thousands of people. Besides hysterical, uncontrollable laughter, the symptoms included respiratory problems, fainting, pain, and even crying attacks. After a year and half, the laughter finally subsided with no traceable cause ever discovered.
The Terroristic Toxic Gas Incident of 1995
In 1995, a group of religious terrorists released toxic sarin gas into the Tokyo subway system. As a result, over 5,000 people poured into hospitals claiming to be experiencing the symptoms associated with toxic gas exposure, including dizziness and nausea. However, after testing patients, doctors found that more than 70% of the people who fell ill were not even exposed to the gas at all.
The Soap Opera Disease of 2006
A famous Portuguese youth soap opera called Morangos com Acucar is very popular to this day. Because of this popularity, in May 2006, over 300 students from at least 14 different schools began reporting symptoms such as rashes and respiratory difficulties—the same symptoms that characters were experiencing on the show at that time. Many schools were forced to shut down because of the mass hysteria.
Teens with Tourette’s in 2011
A fairly recent example: in the fall of 2011, over a dozen teenage girls from an upstate New York high school suddenly developed symptoms that closely resemble that of Tourette’s syndrome, including sudden verbal outbursts, uncontrollable arm movements, and facial tics. Health officials initially thought that the girls may have been exposed to a chemical toxin or infectious agent—but none could be found. Groundwater samples were tested for contamination, but despite protests from the parents, in the end doctors concluded that the girls were experiencing mass psychogenic illness.
