Mass hysteria is a psychological phenomenon which has been documented since the Middle Ages. Political turmoil, environmental stress, fear of the unknown, and the need for social acceptance from our peers can often cause us to behave in an irrational manner, and throughout history, close-knit groups, such as schools and small communities, have experienced inexplicable episodes of mass hysteria.

SEE ALSO: Top 10 Bizarre Cases of Mass Hysteria

Many times, a single unusual incident with a logical explanation has escalated into an epidemic in which those close by imagine they are experiencing similar symptoms. From bizarre behavior to imaginary illnesses, there have been a number of epidemics of mass hysteria throughout history.

10 Dancing Plague Of 1518

We’ve all been tempted to “dance till you drop” when out partying or clubbing. But during the Middle Ages, residents of a French town actually died from dancing.^[1]

In 1518, a case of dancing plague broke out in Strasbourg, in the French Alsace region. Starting with one lone dancer, the footloose outbreak led to over 400 people eventually taking to the streets, dancing nonstop for days on end. Many collapsed from exhaustion, some apparently dying from heart attack or stroke. The Dancing Plague lasted for over a month. Those affected were predominantly female. Few historic notes exist to document the exact cause of the plague.

Town leaders were highly unamused with the ongoing displays of frenetic dancing. Learned physicians at the time suggested that the cause was “overheated blood” in the brain during the hot July days. It has been more recently suggested that a fungus, ergot, in the wheat fields (and thus in people’s bread) may have been the cause. The ergot would have produced reactions similar to LSD.

9 Tanganyika Laughing Epidemic

In 1962, three students at a boarding school in Tanganyika (modern-day Tanzania) began laughing uncontrollably. Their laughter was contagious and soon spread to 95 students at the school.

Bouts of uncontrolled hysteria lasted from a few hours to more than two weeks. Victims also experienced bouts of crying, pain, and fainting. Teachers were unable to conduct lessons with the bouts of hysterical laughing, and the school was forced to shut down for two months while the epidemic was brought under control.

However, the hysteria reportedly spread to surrounding villages and to a number of surrounding schools. Altogether, over 1,000 people were affected.^[2]

Possible toxins from contaminated food or chemicals were ruled out as a cause of the epidemic. No definite medical cause could be found for the laughing disease, which was blamed on the stress of the strict boarding school regime.

8 Mad Gasser

During World War II, residents of the town of Mattoon, Illinois, became convinced they were under attack from a phantom anesthetist who was attempting to gas them as they slept. Victims complained of a strange odor in their homes before being struck with symptoms ranging from paralysis to coughing, nausea, and vomiting.^[3]

The first report came at the end of August 1944, when a resident awoke to a strange smell and suffered a fit of nausea and vomiting. His wife was paralyzed and unable to leave her bed. Police received over 20 similar reports of “gassings” over the following two weeks. Panic ensued as the nightly “gassings” became more prevalent, but no firm sighting of a culprit ever occurred.

All victims made complete and speedy recoveries. Investigators explained the incidents as combinations of odors from a nearby industrial plant and mass hysteria in reaction to reports of a nocturnal prowler.

7 Meowing Nuns

Nuns in religious orders across France and Germany went barking mad during the 15th century. During medieval times, many women entered convents against their will, being forced into a life of celibacy and poverty by their parents. They were condemned to a life of austerity and manual labor. So it is probably no surprise that convent life caused some bizarre behavior from the inmates.

In 1491, a nun in a large French convent began meowing like a cat. Her sisters soon followed her in this strange behavior until the convent was overcome with a “cat imitation” plague. The surrounding villagers were disturbed by this daily caterwauling, to the point that a platoon of soldiers were stationed outside the convent. The nuns were told they would be beaten with rods if they continued to meow.

Various nunneries across the region reported similar epidemics of nuns imitating cats, dogs, and birds, as well as biting viciously. At the time, “demonic possession” was the explanation for the epidemics. However, the repressive conditions in which the nuns lived causing a form of mass hysteria is a more likely explanation.^[4]

6 Strawberries With Sugar Virus

In 2006, over 300 Portuguese schoolchildren were hit with an unexplained illness. Patients complained of dizziness, breathing difficulties, and rashes. The strange illness only affected schoolchildren and was reported in numerous schools around the country.

A teen soap opera called Strawberries with Sugar was identified as the problem. An episode had aired a few days before the outbreak, in which a strange virus was striking children at the show’s school. Apparently, watching the episode had led to children believing that their everyday ailments or allergies were in fact an outbreak of the deadly virus they had seen on television.^[5]

5 Meissen Trembling Disease

Several German schools were hit with an epidemic of trembling in 1905.^[6] A student in Meissen began trembling and twitching as she wrote in October of that year. By May the following year, over 200 students at surrounding schools had been afflicted with the unexplained twitching epidemic. The tremors only occurred when the students were given writing tasks and were not present when performing other lessons.

All the students were high performers, indicating that the stress of having to achieve good grades combined with reports of other instances of the trembling disease contributed to the hysteria. Students were “treated” with electric shocks to “cure” the tremors, which soon subsided after a rest from writing.

4 Hollinwell Incident

A swooning epidemic hit a group of schoolchildren in England’s East Midlands in July 1986.

Over 500 schoolchildren had traveled from all around to compete in a marching band competition. All were assembled and ready to perform, when suddenly, they began collapsing. Around 300 children and adults ultimately dropped at the Hollinwell showground. Mass panic erupted, with emergency crews called in to deal with the growing crisis.^[7]

Victims later complained of having experienced a sore throat and a burning sensation in the eyes. Initial investigations considered a gas leak or contamination from crop dusting as being possible causes of the mass fainting episode. The incident was officially explained as a form of mass hysteria, caused by a combination of tiredness from a long journey to the contest, the heat of the day, and preperformance jitters.

3 Blackburn Faintings

Schoolchildren in the UK town of Blackburn were hit with a fainting epidemic which lasted several days in 1965.

The fainting frenzy began while people were waiting outside the Blackburn Cathedral for Princess Margaret to arrive to officially open the restorations. An early start to the day, with several hours standing in the sun, were initially blamed when 140 children fainted on the grounds.

However, the following day, another 98 patients were hit with the mysterious fainting epidemic at a nearby school. By the end of the week, over 300 children had been affected.

The schools were closed and carefully inspected for a possible cause, with fumes from a nearby factory initially blamed for the fainting episodes. Mass hysteria, leading to overbreathing, brought on by the excitement of the royal visit was finally declared the cause of the fainting fits.^[8]

2 Wurzburg Screaming Epidemic

A nunnery in Wurzburg, Germany, was hit by a screaming epidemic in 1749. As with the meowing nuns a few centuries earlier, it was probably brought on by a combination of boredom and frustration at being forced into a religious life.

The sub-prioress, Sister Maria Renata, initially denied entry into the convent for a young woman who was prone to convulsions. Her decision was overturned, and other sisters within the community began imitating the young woman’s behavior, showing signs of “demonic possession” during services. Victims experienced episodes of screaming, writhing, foaming at the mouth, and entering a trancelike state.

The sub-prioress was coerced into confessing to witchcraft and was beheaded for her crimes against the Church, ending the screaming sessions from the other nuns.

1 Face-Scratcher

In poorly educated communities, villagers will often turn to folklore and mythology to explain the unknown. A belief that aliens were scratching the faces of victims at night sparked mass panic in a town in Uttar Pradesh.

In 2002, residents were reporting a “brightly lit object” that “flies sideways” attacking victims, leaving scratch marks on their faces. Reports ranged from football-sized objects to a UFO the size of a large tortoise that flew at victims, leaving scratches and burn marks.

From an initial isolated incident, rumors of the alien attacker soon spread, sparking widespread panic. Nighttime vigilante groups were set up to scare away the face-scratcher, and residents demanded police capture the extraterrestrial assailants. The only confirmed deaths, however, were from police firing into large crowds to disperse protesters who had gathered to demand action.^[10]

Explanations for the phenomenon ranged from an insect plague to “lightning balls” striking victims as they slept outside. The face-scratcher disappeared suddenly once the monsoon season arrived.

Lesley Connor is a retired Australian newspaper editor who contributes articles to online publications and her travel blog.

Throughout history there have been numerous events that were left mostly unexplained by those who witnessed them. Incidents where people all began to act mysteriously and demonstrate symptoms that seemingly made no sense, like nuns that bark or children that can’t stop laughing. As quickly as they come, they often fade away and few people are any worse for it. When these unexplained conditions pop up, mass hysteria is often the cause. 

10. The Cuban Embassy Attacks

One of the biggest and scariest stories of 2016 and beyond dealt with a series of bizarre illnesses that befell American diplomats at the US Embassy in Cuba. Numerous people came down with serious issues ranging from memory loss to hearing loss to actual, physical brain damage. The Trump White House accused Cuba of deploying some kind of secret sonic weapon against the Embassy. But subsequent research has made this less plausible.

Today, if you look at the Wikipedia page for the attacks, there is a section that dismisses the idea of mass hysteria thanks to JAMA research that concluded the victims had suffered physical trauma. That makes it seem pretty cut and dry. However, that was dated from 2018. 

Other researchers reviewed the data and came up with some critical errors. The reports that staffers at the embassy were riddled with physical ailments offered no context. There is no data whatsoever to back up claims that people suffered injuries, including the nature of the injuries, how they were evaluated, or anything else.

Much of the data relied on for reports cited in the media were based on self-reporting.The idea that the trauma was inflicted by a new sonic weapon took off, except that no one in the world has ever made such a weapon and even those that have tried, like the US government, have had little success with anything similar to what happened in Cuba because physics don’t allow things to work that way. 

What the condition did seem to mirror very well were the symptoms of mass hysteria outbreaks.

9. Salem Witch Trials

Possibly America’s most famous case of mass hysteria, and one of its darkest, the Salem Witch Trials show just how extremely dangerous mass hysteria can get. In the span of one year in the late 1600s, nineteen women were executed by hanging as witches while hundreds more faced persecution for the made up crime. More died in prison and from additional methods of torture.

The local priest had set up an environment where citizens were shamed publicly for their transgressions. When his children began having fits, he accused locals of devilry. Dozens were arrested and put on trial to face bizarre and nonsensical tests to prove whether they were witches. One of the tests involved simply touching someone having one of these fits. If the fit stopped, the person was a witch. Even the presence of a mole, then known as a witch’s teat, was considered direct evidence of witchcraft.

8. Monkey Man

Some cases of mass hysteria seem easier to believe than others. But there’s long been a powerful thread of the supernatural and unbelievable behind many cases that makes it even harder to understand how any of it could have been believed by anyone, let alone many people. Few cases of this are more dramatic than the Monkey Man of New Delhi.

In 2001, residents of New Delhi began reporting sightings of a terrifying half-man, half monkey. The creature traveled across rooftops and had razor sharp metal claws as well as a helmet, presumably for safety.

People reported being attacked and injured by the creature. Worse, several people even died in what was believed to have been attempts to escape the monkey man that resulted in them falling from rooftops. Police were unable to keep up with all the reports, and most of the injuries were chalked up to animal bites rather than supernatural monkey man bites. 

The hysteria was believed to have been fueled not just by superstition but by rolling blackouts that were leaving people unexpectedly in darkness at random times. That likely exacerbated fears and made the situation worse. 

The situation got bad enough at some point that gangs of vigilantes were roaming the streets and had even beat up a very short man, assuming he was the monkey man in question. 

7. Halifax Slasher

In 1938 in Halifax, England, a man with shiny buckles on his shoes and a mallet began attacking women. Two women claimed the man attacked them and set off a panic that saw people taking to the streets in an effort to hunt the villain down. 

Within the first week other attacks were reported, and the weapon changed from a mallet to a knife or razors. Scotland Yard was called to help with the investigation. Vigilantes attacked those that they felt might be the slasher, and things spiralled out of control. Local businesses closed up shop in fear and the panic spread to other towns where attacks also started being reported.

Eventually one of the victims caved in and admitted they had made the attack up and actually harmed themselves. Others did the same, and eventually five of the so-called victims were charged with public mischief.

6. Tanganyika Laughter Incident

Laughter is the best medicine, some people say, but that can’t be the case when laughter is also the problem. That was the case of an incident in 1962 in Tanzania when one girl at a school started laughing and couldn’t stop. School officials tried to make her stop to no avail and laughter contagious as it sometimes is, spread to other students. Nearly 100 of the school’s 159 students were affected. The event started in January and was still going on in March when the school was forced to shut down.

The laughing epidemic spread beyond the borders of the school. People in other towns and other schools fell victim. Some people were affected for days, some for weeks. But it spread around enough that over 1,000 victims were claimed in total and 14 different schools had to be closed over the course of several months. 

Looking back on the incident, most researchers have concluded that the laughter was anxiety-borne. There were a number of contributing factors that were causing excessive stress to students at the time. Unknown expectations of the British run schools and thr fact that the region has just gained independence were likely major causes of unrest in people’s minds. 

5. The Mad Gasser of Mattoon

You’d be forgiven for not knowing much about the town of Mattoon, Illinois. With a population under 20,000 people, it’s a tiny place that isn’t well known for much. Except for the Mad Gasser who plagued the town in the 1940s and who also didn’t actually exist. 

For several weeks, residents in the town reported being attacked by a stranger who exposed them to poisonous gas. Witnesses also corroborated these reports, assuring police they had seen the gasser at work. 

According to reports, victims would be at home and notice an unusual smell. They would then suffer symptoms such as nausea, vomiting, and paralysis. Despite this, police never found a shred of evidence that the gasser existed. In fact, they were able to find much more evidence that there was no gasser, and the strange smells all had easy to pinpoint explanations from spilled nail polish to animals. 

4. Charlie Charlie

The Charlie Charlie Challenge, an adaptation of a much older game simply called “the pencil game” reportedly summoned forth nefarious spirits from beyond and led to death and suicide. None of that was true but it didn’t stop countries like Fiji and Libya from banning the game outright to protect vulnerable children.

The idea of the game is simple. You place a pair of pencils on a sheet of paper, one balanced on the other to create what looks like a plus sign. You have things like names written in each of the four segments of the sheet of paper that are bordered by the pencils. Players ask a question like “which boy likes me?” and the pencil rotates on a pivot point to point at one of the four names you have written on the sheet of paper.

Because the pencil is very precariously balanced, it can move with very little force. Even breathing near it will cause it to rotate. In principle it’s very similar to how a Ouija board works, seemingly moving of its own volition even though there are easy to understand forces at work.

In 2015, however, this game got out of hand. Renamed “Charlie Charlie,” the idea was that kids were asking a spirit or demon to move the pencil. Most stories called it a Mexican demon, despite the English name. Four girls in Colombia ended up going to the hospital as a result, screaming and hysterical, believed to be victims of the supernatural forces at work. Doctors diagnosed it as mass hysteria and nothing more. 

3. The Clown Panic

In 2016, the world was in the grip of clown panic. Chiefly centered in the United States, it had spread to many other countries including Canada, the UK and others. There was a widespread belief that evil clowns were roaming the streets. By October there were dozens of reports coming in every day about sinister clowns. 

The clown panic seems to have started as the result of a single viral marketing stunt in Wisconsin. And stunt was a generous term. A man dressed as a creepy clown was simply standing in street corners looking like a clown.

After that, reports began rolling in from all over the country. Clowns with weapons, clowns making threats, clowns looking ominous. And as near as anyone could tell, none of it was real. Not a single clown actually did anything ominous or dangerous during the entire event.

Police were receiving anonymous reports of clowns trying to lure children and little to no evidence to back anything up. But each subsequent story made national news, and that put more fuel on the fire. The panic lasted for months, throughout the summer and well into the fall. 

By October most media sources were openly calling it all a hoax since no genuine harm had been caused and no real arrests had been made, just false arrests based on false reports. 

2. The Dancing Plague

One of the oldest known cases of mass hysteria took place all the way back in 1518. The incident was actually used as a partial basis for a plot point in Buffy the Vampire Slayer back in the day as well. The residents of Strasbourg, Alsace were struck with an inextricable urge to dance. It became known as the Dancing Plague.

The incident started in July. A woman called Frau Troffea took to the street one day and began to dance. She danced for a day and then two days. She danced for an entire week and by week’s end, she had three-dozen back up dancers. By the time August rolled around, as many as 400 residents of the town were busting moves in the streets.

Doctors, already at a loss to explain most well-known illnesses, settled on “hot blood” as the cause. So the cure was basically an “if you can’t beta ‘em, join ‘em” situation. The town erected a stage and hired a band. 

Instead of fixing the problem, the dancers were just pushed to their breaking point. Reports that people danced themselves to death circulated after the fact and whether or not they are true is still up for debate. 

1. Puppy Pregnancy Syndrome

Generally speaking, mass hysteria is a limited scope phenomenon. It happens for a defined period of time then it goes away when people realize the thing they fear is not real. Such is not the case with puppy pregnancy syndrome in West Bengal, India. This strange mass panic keeps popping up again and again over the years. 

Puppy pregnancy syndrome is tragically very much what it sounds like. Victims are bitten by dogs and then convinced that the dog bite has impregnated them with puppies. The vast majority of people in one small village are convinced this is a very real thing.

According to their beliefs if a dog in a clear state of sexual arousal bites a human, the dog saliva transmits the fetal dogs to the human bloodstream. It doesn’t matter if you’re a man or a woman, the dog babies will take root. That means men are in a far worse position than female bite victims as, according to the belief, they are doomed to birth puppies through their urethra. 

Men are convinced they will die during the delivery process. As a result, there are so-called experts in town who can perform rituals to abort the puppies and save human lives. This must be especially important when you consider some female victims have claimed that they could even hear the puppies in their abdomen barking in the night. 

As silly as it sounds, the syndrome has had serious, real consequences. Victims had to be medicated to overcome serious fears of dogs and obsessive compulsive disorders.