Mass hysteria, a puzzling psychological phenomenon, has been recorded from medieval times to the modern day. The 10 epidemics mass we dive into below reveal how fear, stress, and the urge to belong can push whole groups into wildly irrational actions. Political upheaval, environmental strain, and the simple need to fit in with peers have repeatedly sparked episodes that seem straight out of a fever dream.
Across centuries, tightly‑knit groups—whether a school, a convent, or a small town—have found themselves caught in inexplicable waves of collective behavior. From contagious laughter to mysterious fainting fits, each outbreak tells a tale of how the human mind can turn ordinary stress into extraordinary, sometimes deadly, spectacles.
10 epidemics mass: A quick look at the weirdest collective scares
10 Dancing Plague Of 1518
Picture the summer of 1518 in Strasbourg, a bustling town in the French Alsace region, where one lone citizen burst onto the cobblestones and began an uncontrollable jig. Within days, the feverish dance spread like wildfire, and over four hundred townspeople—mostly women—were caught in a relentless, nonstop boogie that lasted well beyond a month.
The municipal authorities were anything but amused. Physicians of the era blamed “overheated blood” that turned the brain into a perpetual dance‑machine during the sweltering July heat. Modern scholars, however, have suggested a more psychedelic culprit: ergot‑contaminated rye, a fungus that can induce LSD‑like hallucinations when baked into bread.
Regardless of the cause, the spectacle was grim. Many dancers collapsed from sheer exhaustion, some suffering fatal heart attacks or strokes. The town’s desperate attempts to curb the mania—ranging from hiring musicians to playing calming tunes—did little to stop the relentless rhythm that held Strasbourg captive.
9 Tanganyika Laughing Epidemic
In 1962, three students at a boarding school in what is now Tanzania erupted into uncontrollable mirth. Their giggles proved highly contagious, quickly spreading to ninety‑five pupils and turning the entire school into a chorus of hysterical laughter.
The bouts varied in length—from brief, hour‑long fits to prolonged episodes that stretched over two weeks. Alongside the laughter, affected children experienced crying spells, sharp pains, and occasional fainting, making normal classroom instruction impossible. The school ultimately shut its doors for two months while officials tried to restore sanity.
Even after the school closed, the contagion seeped into nearby villages and other schools, eventually touching more than a thousand people. Investigations ruled out food‑borne toxins or chemical exposure, leaving the stressful, regimented life of a strict boarding school as the most plausible trigger for this massive laughing epidemic.
8 Mad Gasser
During the final weeks of August 1944, the quiet town of Mattoon, Illinois, was shaken by reports of a phantom “gasser.” Residents awoke to a strange, sweet odor that preceded a flurry of symptoms: nausea, vomiting, coughing, and even temporary paralysis.
The first documented case involved a man who, after inhaling the mysterious scent, suffered severe nausea while his wife lay paralyzed in bed. Over the next two weeks, more than twenty families reported similar nocturnal attacks, each describing an inexplicable gas that seemed to seep into their homes.
All victims recovered quickly, and investigators eventually attributed the phenomenon to a blend of industrial fumes from a nearby plant and the power of suggestion—mass hysteria sparked by the fear of a nightly prowler. No tangible “gasser” was ever apprehended.
7 Meowing Nuns
In the late 15th century, a French convent became the unlikely stage for a feline‑like chorus. One nun began meowing, and soon her sisters joined in, creating a full‑blown “cat imitation” epidemic that echoed through the cloister walls.
The curious cacophony irritated nearby villagers so much that soldiers were dispatched to guard the convent’s perimeter. Authorities warned the nuns that continued meowing would be met with corporal punishment, yet the bizarre mimicry persisted, spreading to other convents where sisters imitated dogs, birds, and even exhibited violent biting.
Contemporary observers blamed demonic possession, but modern scholars argue that the oppressive, enforced celibacy and austere conditions of convent life likely triggered a collective psychogenic response, manifesting as these animal‑like outbursts.
6 Strawberries With Sugar Virus
In 2006, a wave of mysterious ailments swept through Portuguese schools, affecting more than three hundred children. Victims complained of dizziness, breathing difficulties, and skin rashes—symptoms that seemed to align with a fictional virus featured in the popular teen soap opera “Strawberries With Sugar.”
The show had aired an episode depicting a deadly school‑based virus, and viewers, especially the impressionable youngsters, began to believe that their everyday ailments were actually signs of this televised contagion. The media frenzy turned routine complaints into a nationwide health scare.
Medical authorities eventually traced the panic to the power of suggestion, concluding that the televised storyline had ignited a collective psychosomatic response, not a genuine viral outbreak.
5 Meissen Trembling Disease
In the autumn of 1905, a student in Meissen, Germany, began to experience uncontrollable tremors while writing. By the following May, over two hundred students across nearby schools exhibited the same inexplicable shaking, but only during tasks that required writing.
These high‑achieving pupils were under intense academic pressure, and the spread of rumors about a “trembling disease” seemed to amplify the phenomenon. Some authorities attempted to “treat” the condition with electric shocks, a practice that was quickly abandoned as the episodes subsided after a brief respite from writing assignments.
The episode underscores how performance anxiety, coupled with peer contagion, can manifest as physical symptoms that mimic a genuine neurological disorder.
4 Hollinwell Incident
July 1986 saw a massive swooning episode at the Hollinwell showground in England’s East Midlands. Over five hundred schoolchildren, gathered for a marching‑band competition, were suddenly overcome by a wave of fainting that left roughly three hundred participants collapsed on the field.
Victims reported sore throats and a burning sensation in their eyes. Initial theories ranged from a nearby gas leak to pesticide drift, but investigators ultimately concluded that a blend of travel‑induced fatigue, the sweltering July heat, and pre‑performance nerves sparked a classic case of mass hysteria.
The incident prompted emergency services to intervene, and the competition was halted while medical teams tended to the affected children and adults.
3 Blackburn Faintings
In 1965, the town of Blackburn, England, experienced a baffling fainting epidemic that stretched over several days. The first wave struck when crowds gathered outside Blackburn Cathedral to welcome Princess Margaret for the reopening of the cathedral’s restorations, leaving 140 children fainted under the hot sun.
The following day, another 98 pupils collapsed at a nearby school, and by week’s end the total number of affected youngsters topped three hundred. Initial speculation pointed to industrial fumes from a neighboring factory, but the final diagnosis cited mass hysteria fueled by over‑breathing and the excitement surrounding the royal visit.
Schools were temporarily closed for thorough inspections, and the episode remains a textbook example of how heightened emotion and environmental stress can combine to produce a community‑wide medical mystery.
2 Wurzburg Screaming Epidemic
In 1749, the convent of Wurzburg, Germany, was haunted by a terrifying screaming epidemic. The sub‑prioress, Sister Maria Renata, initially denied entry to a young woman prone to convulsions, but after the decision was overturned, other sisters began imitating the woman’s frantic behavior.
The resulting episodes featured shrieking, writhing, foaming at the mouth, and trance‑like states that terrified both the nuns and the surrounding community. Authorities labeled the phenomenon as demonic possession, and Sister Maria Renata was coerced into confessing witchcraft.
She was subsequently beheaded, an act that abruptly ended the screaming fits. The tragedy highlights how religious oppression and fear could manifest in violent collective psychosis during the era.
1 Face‑Scratcher
In 2002, the Indian state of Uttar Pradesh was gripped by a night‑time terror: locals reported a luminous, sideways‑flying object that allegedly scratched victims’ faces, leaving mysterious marks and burns. Descriptions varied from football‑sized orbs to tortoise‑shaped UFOs that swooped down on unsuspecting villagers.
The rumors spread like wildfire, prompting the formation of vigilante night patrols intent on scaring away the alien attacker. Police intervened, and in a tragic turn, fired into crowds, resulting in several deaths. Investigators later suggested the scratches could have been caused by insects or “lightning balls,” but the panic subsided only after the monsoon season arrived.
The episode serves as a stark reminder of how folklore and fear can combine to produce a full‑blown mass hysteria, especially in communities with limited scientific resources.