Mass psychogenic illness

Mass psychogenic illness (MPI)—also known as mass sociogenic illness, mass psychogenic disorder, epidemic hysteria, or mass hysteria—describes the rapid spread of physical symptoms through a close-knit group, even though no infectious germ or virus is causing the outbreak. The symptoms arise from a disturbance in the nervous system that can involve excitation, loss of function, or altered function. People unconsciously experience these physical complaints, but medical tests find no known organic cause.

**Signs and symptoms** Timothy F. Jones of the Tennessee Department of Health compiled a list of the most common symptoms seen in outbreaks between 1980 and 1990.

**Causes and risk factors** MPI is different from other collective delusions because it involves real physical symptoms. Typical features of an MPI outbreak include: symptoms that have no clear physical cause; symptoms that are mild and temporary; a rapid start and quick recovery; the outbreak occurs in an isolated or segregated group; there is a high level of anxiety; the illness spreads through sight, sound, or word of mouth; and it tends to move from older or higher-status people down to younger or lower-status people.

British psychiatrist Simon Wessely distinguishes two forms: - **Mass anxiety hysteria** – episodes of acute anxiety, mostly in schoolchildren, with no prior tension, spreading quickly through visual contact. - **Mass motor hysteria** – abnormal movements or behaviors, occurring in any age group, with prior tension present. The first cases can be identified, and the spread is gradual. Outbreaks can be prolonged.

Some researchers disagree with Wessely’s strict division, noting that many outbreaks show features of both types. The DSM-IV-TR does not list MPI as a separate diagnosis, but its section on conversion disorder notes that in “epidemic hysteria,” shared symptoms develop in a limited group of people after they are exposed to a common trigger.

**Prevalence and intensity** MPI outbreaks most often affect children and adolescents, with females disproportionately impacted. Research has not consistently supported the idea that people who are extraverted, neurotic, or have lower IQs are more likely to be affected. Bartholomew and Wessely state that “it seems clear that there is no particular predisposition to mass sociogenic illness and it is a behavioral reaction that anyone can show in the right circumstances.”

Intense media coverage tends to make outbreaks worse, and the illness can return after the initial episode. John Waller advises that once authorities determine an illness is psychogenic, they should not give it credibility. For example, in a Singapore factory case, calling in a medicine man to perform an exorcism seemed to prolong the outbreak.

**History**

**Medieval period** The earliest studied cases of epidemic hysteria are the dancing manias of the Middle Ages, such as St. John’s dance and tarantism. People believed these were caused by spirit possession or the bite of a tarantula. Those affected would dance in large groups, sometimes for weeks, often stripping, howling, making obscene gestures, or laughing and crying until they died. Dancing mania was widespread across Europe.

Between the 15th and 19th centuries, motor hysteria was common in nunneries. Many young women were forced into convents by their families, where they took vows of chastity and poverty and lived highly regimented lives with strict discipline. The nuns would show a range of behaviors, usually blamed on demonic possession, including using crude language and acting suggestively.

In the English translation of Hecker’s *The Epidemics of the Middle Ages* (1844), translator and epidemiologist Benjamin Guy Babington added a personal note. He recalled reading an uncited French medical journal about a large convent in France where the nuns began meowing like cats. They meowed for hours each day until they were beaten with rods to stop. Priests were often called in to perform exorcisms.

**In factories** MPI outbreaks occurred in factories after the Industrial Revolution (1760–1840) in England, France, Germany, Italy, Russia, the United States, and Singapore.

W. H. Phoon of the Singapore Ministry of Labour described six outbreaks in Singapore factories between 1973 and 1978. These featured: (1) hysterical seizures with screaming and violence, where tranquilizers did not help; (2) trance states in which workers claimed to be speaking under the influence of a spirit or jinn; and (3) frightened spells, with workers feeling unprecedented fear, cold, numbness, or dizziness. Outbreaks usually subsided in about a week. Often a bomoh (medicine man) was called in to perform a ritual exorcism, but this was not effective and sometimes made the outbreak worse. Females and Malay workers were disproportionately affected.

A notable case is the “June Bug” outbreak of June 1962, a peak production month. At a dressmaking factory in a textile town in the southern United States, 62 workers—59 of them women—developed severe nausea and skin rashes. Most cases occurred during the first shift, where four-fifths of the workers were female.