When Minds Unite: 50 Cases of Mass Hysteria That Defy Explanation

In 1962, Tanzania (then Tanganyika) experienced a laughter epidemic that originated in a girl's school, spreading to over 1,000 people with symptoms lasting for months, including chronic laughter, hysterical crying, aimless running, and violent outbursts. The epidemic resulted in the closure of fourteen schools, as it is believed to have originated with anxiety-induced laughter in one schoolgirl and triggered a chain reaction in the region. Researcher Christian Hempelmann suggested that the laughter did not alleviate suffering but rather served as an expression of the psychic pressure these individuals were facing.

In 2016, Elsa Perea Flores School in Tarapoto, Peru, experienced a mass hysteria outbreak, affecting nearly 100 children aged 11 to 14. The students reported terrifying visions of a man in black attempting to kill them, along with seizures, fainting, convulsions, delirium, and repeated screaming. Locals attributed the hysteria to demonic possession, suggesting the children may have played with an Ouija board before the attacks.

In June 1999, Coca-Cola withdrew 30 million cans and bottles from Belgian shelves following over 100 reports of illness, including stomach cramps and nausea. Despite concerns about airborne toxins, an investigation by Belgium's Health Council suggested mass hysteria, emphasizing the role of media, health authorities' radical measures, and deficient communication by Coca-Cola. The company quickly rebounded, with sales recovering within weeks.

In 1964, a leprechaun hysteria swept Liverpool, with thousands of children and adults convinced they would find the mythical creatures in Jubilee Park. Police intervention became necessary, setting up a protective presence in the park due to the escalating danger of injuries, while the leprechaun hunt eventually extended to St. Chad's churchyard before gradually fading. The panic's origins ranged from alleged sightings of flying objects from Ireland to an incident involving a man named Brian Jones, who, when mistaken for a leprechaun, contributed to the escalating rumors by yelling gibberish and throwing turf.

In May 2006, Portuguese schools experienced an outbreak of the "Morangos com Açúcar Virus," with over 300 students at 14 schools reporting symptoms mirroring those in a recent episode of the popular youth soap opera. Symptoms included rashes, difficulty breathing, and dizziness, leading to school closures. The Portuguese National Institute for Medical Emergency attributed the illness to mass hysteria, causing concern among parents about the series' influence on children and teenagers.

In May 2001, New Delhi experienced reports of a mysterious monkey-like creature attacking people at night, described as about four feet tall with black hair, a metal helmet, claws, glowing red eyes, and buttons on its chest. Theories about the creature ranged from a Hindu god's avatar to an Indian Bigfoot or a cyborg with a motherboard under its chest fur. Panic led to injuries, with two or three people reportedly dying from jumping off buildings or falling down stairs in an attempt to escape the perceived attacker.

The Dancing Plague of 1518 in Strasbourg, France, was a case of dancing mania where numerous people danced for days without rest. It began when a woman, Frau Troffea, started dancing fervently in the street, and within a week, 34 others joined. The phenomenon resulted in around 400 dancers, most of whom eventually died from heart attacks, strokes, or exhaustion. The reason for the dancing and whether it was voluntary remain unclear.

During World War II in Mattoon, Illinois, residents reported experiencing symptoms like paralysis, coughing, nausea, and vomiting, believing they were targeted by a phantom anesthetist. The panic started in August 1944, with over 20 reports of "gassings" in two weeks. Investigators attributed the incidents to odors from a nearby industrial plant and mass hysteria fueled by reports of a nocturnal prowler, and all victims eventually recovered.

In the 15th century, nuns in France and Germany exhibited bizarre behavior, with some imitating animals like cats, dogs, and birds. In 1491, a nun in a French convent started meowing, leading her sisters to follow suit, creating a "cat imitation" plague. Soldiers outside the convent brandished rods and threatened the nuns if the behavior persisted, while similar epidemics were reported across various nunneries. While "demonic possession" was the contemporary explanation, the more likely cause was mass hysteria stemming from the repressive conditions in which the nuns lived.

In 2002, a town in Uttar Pradesh, India, experienced mass panic as residents believed aliens were scratching victims' faces at night. Reports described a "brightly lit object" flying sideways, leaving scratch and burn marks on victims. The panic led to nighttime vigilante groups and demands for police intervention, resulting in confirmed deaths from police firing into crowds. Explanations ranged from insect plagues to "lightning balls," and the face-scratcher phenomenon ceased with the onset of the monsoon season.