20 Of History’s Strangest Mass Hysteria Events

In Strasbourg (then part of the Holy Roman Empire) in mid-1518, a woman went out into the street and began dancing, and she just didn’t stop. Soon, people started to join her. Within a couple of weeks, news reports said there were hundreds of people dancing uninterrupted. From all the dancing, people were collapsing from exhaustion, and some people died. Local authorities thought that all the movements could ‘cure’ the dancing sickness, so they encouraged and supported dancing by sending out musicians; this could have easily started an even larger outbreak. Although the cause of the strange phenomenon is unknown, a lot of historians like to assume that it may have been a mass psychogenic event, considering the extreme social tensions of that time and the deeply rooted religious beliefs.

In Colonial Massachusetts, something strange began happening to the girls of the town. They started to have spasms, complained about the presence of invisible supernatural entities, and exhibited other bizarre behaviors. By now, the already heightened state of paranoia in the Puritan-driven community resulted in rampant accusations of witchcraft, especially against the socially weak and disenfranchised. This resulted in over 200 accusations and 20 executions, most of them directed at women. Such a combined, coherent mass behavior can often only be the result of psychological suggestion.

A boarding school situated in what is now the East African country of Tanzania became the epicenter for what is now known as the great Tanzanian laughing epidemic. The initial outbreak occurred when several students began to laugh uncontrollably. This case of mass hysteria spread to other schools and eventually to the neighboring villages. The outbreak lasted several months and caused the closure of several schools. The cause of the bizarre phenomenon was never established. Researchers suggest the outbreak was caused by the stress and continued emotional suppression that the students at the school were forced to endure.

Orson Welles adapted H.G. Wells’ science fiction novel The War of the Worlds, which tells the story of a Martian invasion of Earth, into a radio broadcast in 1938. This adaptation was in a newscast style, which tricked some listeners into thinking they were witnessing the invasion. There were disclaimers, but many listeners tuned in at different points, and most of the disclaimers were missed. Newspapers the next morning described listeners fleeing their homes and jamming phone lines. Media historians have since shown those accounts were wildly exaggerated. Ratings data suggest only about 2% of the radio audience was even tuned in, and newspapers, then losing advertising money to radio, had every reason to paint the new medium as reckless.

Numerous students in Le Roy, New York, began developing tics and strange speech, with some showing signs of involuntary movements. The new speech and physical symptoms spread to other students, fueling fears that a school-based environmental or toxic factor was responsible. After testing for the impact of possible environmental or toxic factors, the results were negative. The outbreak was diagnosed as a mass psychogenic illness, which is a diagnosis for symptoms that spread socially rather than through infection. Among these, perhaps the most significant of the causative factors was the presence of the media, the social conditions, and the stress experienced by the school children, which, in this case, also included a significant worsening effect on the condition of the students.

In 2016, mass hysteria, as described by officials and medical personnel, was observed in several secondary schools in Kelantan, Malaysia. Reportedly, both teachers and students were affected. An incident at SMK Pengkalan Chepa 2 was widely covered as students were seen fainting, yelling, and having serious panic attacks during class. Reportedly, several students saw supernatural, dark, and shadowy beings, as well as a Pontianak, a female spirit in local lore, prior to fainting or losing consciousness. Many cases were similar to a mass epidemic occurring at a school, resulting in the closure of the school and an emergency response by the education and health authorities. Subsequent investigations conducted by the Malaysian authorities tried to explain the phenomena and reported the incidents as anxiety, stress, and other psychological issues.

Beginning in the 1960s, accounts emerged of American factory employees becoming faint, nauseous, dizzy, and experiencing severe headaches; toxic atmospheric gas leaks were suspected. Many reported symptoms, even though no one was found to be leaking gas or exposing employees to toxic chemicals. Further investigations of suspected gas leaks to explain the rapidly growing number of sick workers provided no evidence. The missing link in the equation was found only later: the growing number of sick workers started to believe ill symptoms would manifest to them in one form or another. Incredibly, the absence of physical causes led to the most severe manifestations of illness due to workplace anxiety.

During periods of political and ethnic unrest in Kosovo, a region in Southeast Europe in the central Balkans, there were reports of students exhibiting clusters of illnesses, including nausea and even fainting in several cases, among entire classrooms. The episodes caused mass disruptions to classes. Medical and environmental studies reported no evidence of any pathogens. Official researchers attributed these events to mass psychogenic illness that occurs where there is substantial anxiety within an unstable, violent and unpredictable social environment, though ethnic Albanian doctors and families disputed that conclusion and maintained the students had been poisoned.

In the early 1960s, dozens of employees in a U.S. textile factory experienced nausea, dizziness, fatigue, and numbness. Fear spread throughout the factory that the cause was a toxin or a bug called the June bug. There were even claims of bites. Testing did not find any pathogens or toxins, and an exhaustive search did not find any insects. Investigators decided the cause was likely a case of mass psychosomatic illness. They based this on the combination of stress from long work hours and the illness spreading rapidly as panic set in.

In November 1938, mass hysteria broke out in an English town when a mysterious street slasher allegedly began to stalk townspeople and later vanish into thin air. People claimed to have actually spotted the “slasher” as the hysteria began to spread. The reports soon began to merge and were about to cause a state of mental panic. Investigators found no proof based on the community claims, and many of the supposed witnesses admitted to having fabricated or highly exaggerated their stories. The serial slasher was assumed to be a figment of the community’s imagination and a result of mass paranoia.

In May 2001, a legendary ‘Monkey Man’ urban legend gripped the citizens of Delhi, India. This ‘Monkey Man’ allegedly attacked citizens at night. Descriptions of the ‘Monkey Man’ are of a hairy, monkey-like creature with glowing, red eyes and metallic claws. Numerous reports multiplied, and thousands of emails and phone calls bombarded the police. Many citizens chose to either sleep outdoors to guard their neighborhood or simply stay awake all night. Injuries occurred during stampedes, and numerous citizens panicked and fled. At least two people died falling from rooftops and stairwells as they ran. Investigators looked deeply into the ‘Monkey Man’ and found no trace of the legendary creature. The ‘Monkey Man’ scare is now a classic example of mass hysteria.

In 1954, people started finding small cracks in their windshields in Seattle, Washington. Instead of just being concerned, there was an initial panic from people thinking it was from fallout concerning radiation, industrial pollution, or just strange particles floating in the air. Reports spread quickly as many people found the same issues in their cars. Schools, businesses, and officials received an excessive number of complaints and requests to look into the issue. There was no environmental cause found by officials and it was later thought that the cracks had always been there, but were only noticed when people started complaining.

Symptoms of spirit possession have been exhibited by school children and youth in Madagascar from the late 20th century and onwards. Incidents typically begin with one or a few individuals collapsing, screaming, or going into a trance. These actions stimulate the same reaction in peers and escalate the incident. Some of these instances have even resulted in the closure of the school due to the overwhelming magnitude of incidents. Research has not uncovered an infectious disease that has caused the symptoms. The rapid spread of symptoms is thought to be due to group dynamics, cultural beliefs, and emotional stress.

In 1965, a reported illness of mainly teenage girls at a Blackburn, England school described symptoms of dizziness, nausea, fainting, and headaches. It all started with a few girls who collapsed during the school day, and then the remaining girls began to exhibit the symptoms shortly after. This caused a school-wide problem, and parents even began to take their children out of the school. Investigations were performed to try to figure out the problem, but there was no evidence to show that toxins or infections were the cause. The problem was then covered as mass psychogenic illness. It was most likely the result of a combination of stress and a social problem during the close monitoring of school activities among the students.

In the 2000s and 2010s, Bangladeshi news featured incidents that described the environment within a school as chaotic. Groups of girls, thought to be possessed by spirits, would suddenly scream, cry, and trance out. This chaos would actually start with one girl collapsing to the ground. This usually spreads through the entire classroom. Sometimes the school would have to shut down temporarily. In the local community, they would believe these events to be the product of supernatural events. There were no toxins or infectious diseases found to be the cause of such symptoms. Researchers believe that these incidents would best be classified as a psychogenic illness, in which the symptoms were actually caused by stress and suggestibility of the classrooms.

In October 1917, in Fátima, people claimed to have seen strange solar events after a series of Catholic visions of the three shepherd children. During the last of these events, large crowds formed to see the “miracle” (of the apparitions). They claimed to have seen the sun change colors, spin in the sky, and even move towards the earth before returning to normal. The political and social events of the time, coupled with the people’s strong sentiments, contributed to the shared visions. To skeptics, the event is an excellent example of mass suggestion and collective perception, interpreted by means of the beliefs of the crowd.

Between 1632 and 1634, several Ursuline nuns in Loudun, France, claimed to be experiencing episodes of demonic possession that manifested through convulsions and trance-like states that occurred when they were praying. The outbreaks that first occurred in a convent of Mother Jeanne des Anges caused some nuns to claim that they had been tormented by invisible forces. Eventually, the attention shifted towards a local priest accused of witchcraft, Urbain Grandier. His trial became a major political and religious spectacle, and he was ultimately executed by burning at the stake. Modern historians generally interpret the events as a mix of psychological contagion, religious fervor, and political manipulation.

A Coca-Cola-related health incident occurred in June 1999, when reports of illnesses related to the consumption of Coca-Cola products were widely spread. The reportedly affected were in Belgian schools, mostly staff and students. Prominence of headaches, nausea, dizziness, and stomach-related pains and evacuations contributed to the hysteria. Early theories of the case evoked hysteria and attributed poisonous gas to Coca-Cola products. In response to the initial fears, Coca-Cola temporarily recalled a vast quantity of its products. Health investigations showed no evidence of poisonous gas or harmful substances in any Coca-Cola products. Belgian researchers suggested a related phenomenon may be classified as mass psychogenic illness, whereby the rapid propagation of symptoms and anxiety in a school cluster generated an overactive response to the symptoms of an illness.

In 1933, several Virginia communities faced troubling events that were reported to involve an unknown person releasing noxious gas into homes during the night. As victims claimed to have been attacked in the night, they reported symptoms of throat pain, headaches, dizziness, and nausea. In response, people worked to secure their homes, and local authorities responded with increased patrols. In the height of the panic and fear, police and health officials found no signs of gas attacks, and there were no suspects involved in the reported attacks. Given the lack of evidence, the events are best described as a case of mass hysteria, collective delusion, with the suggested symptoms being driven by anxiety and fear, and spread by rumors.

During the 2010s, there were multiple reports from schools all over Sri Lanka regarding an occurrence where a large number of students, mainly adolescent girls, would faint or lose consciousness, or feel dizzy during class. In a few documented cases, a large number of students experienced the same symptoms on the same day. There were many fears regarding the students being exposed to toxins, the food being contaminated, and environmental threats. Medical investigations were conducted by the local health authorities, and they concluded that there were no known causes for the symptoms. Researchers suggested that these episodes were consistent with mass psychogenic illness.