Hektoen International

A Journal of Medical Humanities

The enigma of mass psychogenic phenomena

Umut Akova
Atlanta, Georgia, United States

Dancing mania on a pilgrimage to the church. 1642 engraving by Hendrick Hondius after a 1564 drawing by Pieter Brueghel the Elder. It is presumed that Breugel was an eyewitness to these events. Via Wikimedia.

In the stifling heat of 1518, Strasbourg, France was gripped by a bizarre spectacle: a mass outbreak of uncontrollable dancing. In the city’s streets, men, women, and children danced wildly, their movements frantic and seemingly without purpose. Despite efforts to stop the madness, the frenzy continued unabated, with fear and confusion spreading among the population as scores of people died of exhaustion from dancing.1

Throughout history, humanity has been captivated by enigmatic occurrences that defy conventional explanation. Among these perplexing phenomena, mass psychogenic illness is a fascinating yet often misunderstood aspect of human behavior and collective psychology.2 From the medieval outbreaks of dancing mania to the modern-day mysteries of Havana syndrome, the spectrum of mass psychogenic illness spans centuries and continents, leaving an indelible mark on societies and challenging the boundaries of medical understanding.

The earliest documented instances of mass psychogenic phenomena can be traced back to the seventh century, where historical records from the Byzantine Empire describe mysterious episodes of collective hysteria and mass fainting.3 These episodes, often attributed to religious fervor or demonic possession, foreshadowed the patterns of mass psychogenic illness that would recur throughout history. Beginning in the fourteenth century and persisting for centuries, outbreaks of dancing mania gripped communities in Europe, compelling individuals to engage in frenzied and uncontrollable dancing for extended periods. The phenomenon, often attributed to supernatural causes or divine punishment, underscored the limited understanding of mental health in medieval society.4

Ergot poisoning,5 encephalitis,6 and typhus7 have all been posited as explanations for dancing mania. Ergot poisoning, caused by the consumption of rye contaminated with the Claviceps purpurea fungus, can lead to hallucinations and convulsions from the alkaloids produced by the fungus. Encephalitis, characterized by inflammation of the brain, and typhus, a bacterial infection spread by fleas and lice, both have neurological symptoms that could contribute to the hyperactive and frenzied behavior observed in cases of dancing mania. However, while these medical conditions may have played a role in certain outbreaks, the precise cause of dancing mania remains elusive and likely involves a complex interplay of environmental, social, and psychological factors.

The twentieth century witnessed a resurgence of mass psychogenic phenomena, albeit in different forms. From the mysterious symptoms reported by American diplomats in Havana, Cuba to the perplexing outbreaks of mass fainting in schools and workplaces, manifestations of mass psychogenic illness have continued into the modern era. One notable example is the Tanganyika laughter epidemic of 1962, where uncontrollable laughter spread rapidly among schoolchildren in a school in eastern Africa and eventually affected about a thousand individuals in fourteen different schools.8 Despite extensive investigations, the underlying cause of the laughter epidemic remained elusive, highlighting the complex nature of mass psychogenic phenomena and the challenges of attribution.

Among the most recent and intriguing manifestations of mass psychogenic illness is Havana syndrome, named after the Cuban capital where it was first reported. Beginning in the early 2010s, American diplomats and intelligence officers stationed in various countries began experiencing a range of unexplained symptoms, including headaches, dizziness, and cognitive difficulties. Initially attributed to covert sonic or microwave weapons, subsequent investigations failed to identify definitive evidence linking the symptoms to external attacks.9 The ambiguity surrounding Havana syndrome has fueled speculation about psychological or psychosomatic factors playing a role, underscoring the complexity of diagnosing and understanding mass psychogenic phenomena in a contemporary context.

Vaccines have also sparked concerns and reports of adverse reactions, which in some cases have resembled patterns of mass psychogenic illness.10 During the COVID-19 pandemic, the rapid development and deployment of vaccines, coupled with the unprecedented scale of the vaccination campaign, resulted in reports of adverse reactions, which were at times unsubstantiated and resembled patterns of mass psychogenic illness. The intense media coverage and public scrutiny surrounding COVID-19 vaccines heightened anxiety and uncertainty among some individuals, making them more susceptible to psychosomatic symptoms or the misattribution of unrelated symptoms to vaccination. In some cases, clusters of individuals experiencing similar symptoms after vaccination have led to rumors and speculation, further exacerbating anxiety about the vaccines. The psychological impact of the pandemic, including fear of illness and social isolation, also contributed to heightened stress levels, which can exacerbate the perception of adverse reactions to vaccines.11

At the heart of mass psychogenic illness lies the intricate interplay of psychological mechanisms and social dynamics. Stress, anxiety, and collective fear have been identified as common triggers for psychosomatic symptoms, leading to the manifestation of physical ailments with no discernible organic cause. The phenomenon of suggestibility, wherein individuals within a close-knit community influence each other’s perceptions and behaviors, plays a pivotal role in amplifying the spread of psychogenic symptoms. Additionally, cultural beliefs, societal norms, and historical context shape the presentation and interpretation of mass psychogenic phenomena, further complicating the diagnostic process and treatment approaches.12

From the medieval fervor of dancing mania to the modern-day mysteries of Havana syndrome and vaccination reactions, the spectrum of mass psychogenic illness encompasses a diverse array of phenomena that continues to captivate and confound. Unraveling the enigma of mass psychogenic illness will require a multidisciplinary approach that integrates insights from psychology, neuroscience, sociology, and cultural studies.


  1. John Waller. “A forgotten plague: making sense of dancing mania.” The Lancet 373, no. 9664 (2009): 624-625.
  2. Erica Weir. “Mass sociogenic illness.” Canadian Medical Association Journal 172, no.1 (2005): 26-36.
  3. Neil McAlister. “The Dancing Pilgrims at Muelebeek.” Journal of the History of Medicine and Allied Sciences 32, no. 3 (1977): 315-319.
  4. Robert Bartholomew. “Tarantism, dancing mania and demonopathy: the anthro-political aspects of ‘mass psychogenic illness.’” Psychological Medicine 24, no. 2 (1994): 281-306.
  5. Nadine Metzger. “Poisoning, Ergotism, Mass Psychosis. Writing a History of Ancient Epidemics Beyond Infectious Diseases.” Historical Social Research no. 33, Supplement: Epidemics and Pandemics – The Historical Perspective (2021): 316-329.
  6. Robert Bartholomew and Francois Sirois. “Occupational Mass Psychogenic Illness: A Transcultural Perspective.” Transcultural Psychiatry 37, no. 4 (2000): 495-524.
  7. Michael Colligan and Lawrence Murphy. “Mass psychogenic illness in organizations: an overview.” Journal of Occupational and Organizational Psychology 52, no. 2 (2011): 77-90.
  8. Christian Hempelmann. “The laughter of the 1962 Tanganyika ‘laughter epidemic.’” Humor – International Journal of Humor Research, 20, no. 1 (2007): 49-71.
  9. Julian Barnes. “New Studies Find No Evidence of Brain Injury in Havana Syndrome Cases.” The New York Times, March 19, 2024.
  10. John Clements. “Mass Psychogenic Illness After Vaccination.” Drug Safety 26, no. 9 (2003): 599-604.
  11. Ram Sapkota, Alain Brunet, and Laurence Kirmayer. “Characteristics of Adolescents Affected by Mass Psychogenic Illness Outbreaks in Schools in Nepal: A Case-Control Study.” Frontiers in Psychiatry 11 (2020).
  12. Wentao Yan. “A systematic review of research developments in mass psychogenic illness.” Journal of Education, Humanities and Social Sciences 9 (2023): 150-157.

UMUT AKOVA is a first-year medical student at the Emory University School of Medicine interested in the intersection of medicine, history, and art. He calls Ankara, Turkey his home.

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