In medical terms, mass hysteria or collective delusions are described as the spontaneous manifestation of a particular behavior by a considerable number of people – either from a phantom illness or an inexplicable event. Often occurring in places where small, tight-knit groups of people are gathered together, mass hysterias generally spread rapidly but are relatively short-lived affairs. Found in most societies, with hysterical outbreaks that can be traced back throughout history, they remain a baffling reminder of the power of the human mind.

From nuns that began to meow like cats to an entire city that couldn’t stop dancing, here are the most bizarre cases of mass hysteria ever recorded in history.

1. The Trouble with Nuns

According to the book Epidemics of the Middle Ages by J. F. C. Hecker, a baffling case of mass hysteria gripped a secluded convent in France. It all began when one nun began to meow like a cat, an animal that is closely associated with the Devil in Catholicism. Soon others in her company began to meow as well. Together they would sometimes meow for hours at a time. To contain the situation soldiers were brought in and tasked with whipping and beating the nuns until they promised to stop.

A similar case occurred in Germany during the 15th century, when nuns began to bite one another. When the news traveled, other nunneries in the area started experiencing the same problem. Soon the biting epidemic had spread as far as Holland and Rome, with no clear explanation as to why this was happening. According to reports from the time, the biting eventually ceased due to the nuns exhaustion. The bizarre behavior of both cases is generally credited to the period’s intense belief in the supernatural, in addition to the fact that many of the women had been forced into convents by their families to live a lifestyle that demanded celibacy, poverty, and hard manual labor. It’s little wonder nuns found themselves particularly susceptible to episodes of hysteria.

2. The Deadly Dancing Mania

In the July of 1518, as disease and famine swept through the streets of Strasbourg, France, a strange thing happened; a woman named Troffea began to dance. After a week others had joined her, and by August over 400 people lined the city streets silently dancing. Doctors were mystified but came to the conclusion that the incessant dancing was caused by a fever and recommended the sufferers continue until the fever burned itself out. The city governor’s constructed a stage and brought in a band and professional dancers to dance alongside the inflicted. Soon people began to pass out from heat exhaustion, some even died. The dancing mania only ended when people were forcibly removed from the streets and taken to shrines to pray to St. John the Baptist or St Vitus to cure them of the dancing curse.

Stranger still, this incident was not the first of its kind. In the 13th century in Aachen, Germany, the dancing plague or ‘St John’s Dance’ as it was also known caused thousands of people to start dancing with uncontrolled emotion. Italy, Holland, and Switzerland also experienced these strange bouts of dancing plagues, with the last taking place as late as the 17th century.

3. The Tanganyika Laughers

You’ve probably heard of infectious laughter, but nothing like this. In 1962, three young girls from a boarding school in Tanzania began to laugh uncontrollably. They would laugh for hours at a time without being able to stop. The laughter spread to other children and became so widespread that the school was forced to shut down. This, however, did not the end of the epidemic, as some of the girls spread their laughing sickness when they went home. By May of that year, there were 217 reported cases of the laughing flu in the area. Most of the afflicted were school-age children. When June came and went and the laughter had continued to spread, then it all stopped as suddenly as it began. In its entirety, the laughing flu caused 14 schools to close with around 1,000 cases of laughing fits recorded.

4. The Muhnochowa

In 2002, the people of Uttar Pradesh in India reported seeing an alien spacecraft that would burn the flesh on people’s face. It was given the name “Muhnochawa,” or, “Face-Scratcher.” There were seven deaths associated with the alien, and the local police deputy did nothing to calm matters when he made the statement that these afflictions were brought on by some sort of anti-national genetically engineered insect. Villagers stormed police headquarters and demanded protection, inciting a riot and leaving one person dead. People even committed suicide to save themselves from these foreign attackers. In the end, the national government had to step in and send agents to investigate the case. They attributed the whole outbreak to mass hysteria and claimed that the burn marks and injuries were entirely self-inflicted.

5. New York Tourette Epidemic

Tourette Syndrome is characterized as a vocal and/or physical tick that is uncontrollable. It’s a rare neuropsychiatric disorder, which made it all the more strange when a New York school experienced an outbreak of tourette syndrome in 2011. After several schoolchildren began to display Tourette like symptoms, parents became concerned that there was some sort of toxin that was causing this outbreak, though researchers concluded that there was nothing unusual about the environment. Dr. Laszlo Mechter came to the conclusion that this outbreak was the result of conversion disorder. This basically means that, though the students were experiencing real symptoms, they were not experiencing actual tourette syndrome.

6. The Halifax Slasher Panic

The Halifax Slasher panic began on November 16th, 1938 in Halifax, England, when two women entered the local police station with head wounds. They told the police that a man had attacked them with a razor blade, but upon investigating the police could find no evidence at the crime scene. Soon word of the attack spread and over the following days, more people came forward, all with cuts and knife wounds. Vigilante groups began to roam the streets, attacking men who appeared suspicious. With the local police stumped by the lack of evidence and with no suspects, detectives from Scotland Yard were called in to help. But just as the detectives began their investigation the case took an unexpected turn.

During questioning the victims began confessing they had actually injured themselves after hearing about the so-called Halifax Slasher. When nine of the 12 victims confessed to self-harm, the police closed the investigation. Five were subsequently charged with public mischief offenses and four were sent to prison for their part in the slasher panic.

7. The Twitching Outbreak

A high-school in Louisiana experienced a strange moment of mass hysteria in 1939 when one of their students inexplicably began to feel an uncontrollable twitch in her right leg. After attending the school’s annual homecoming dance her leg began to twitch along with the music. This continued in school the next day and soon spread to several of her female classmates. Concerned parents began to pull their children out of school. As fear spread, so did the twitching phenomenon, until it suddenly and ultimately ended within a week. Sociologists explain that there was no real condition, and that this was merely a case of mass hysteria.

8. The Salem Witch Trials

One of the most well-known examples of mass hysteria in American history, the Salem Witch trials resulted in around 20 deaths and an enduring legacy that continues to this day. Already rife with rumors of witchcraft, in 1692 Betty Paris and Abigail Williams began displaying strange tendencies by screaming and flailing around uncontrollably. Doctors declared the girls were bewitched, and along with Ann Putnam the three young girls began identifying women in town as witches. It started with societal outcasts but eventually grew as more and more accusations were made. By the time the trials ended a year later, over 200 people had been accused of practicing witchcraft, 19 people had hanged, one man had been pressed to death by stones and seven had died in jail awaiting execution.

Although Salem, Massachusetts remains a popular tourist attraction for history and witchcraft enthusiasts, it is widely accepted that these accusations and executions were a result of an extreme case mass hysteria, in part propelled along by religious extremism, isolationism, false accusation and a total failure of the system.

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