Mass psychogenic illness
Real symptoms that spread through a group by anxiety and suggestion rather than by any germ or poison.
Mass psychogenic illness, sometimes called mass hysteria, is the spread of real physical symptoms, such as fainting, headaches, nausea, trembling or uncontrollable laughing, through a group of people when no germ, poison or other physical cause can be found. The symptoms are genuine, not faked. What spreads is anxiety and expectation, passed from person to person by seeing and hearing others affected.
Outbreaks tend to share features. They often begin in close-knit groups such as schools, factories or villages, frequently at times of stress; they spread along lines of sight and friendship; and they tend to fade when the group is separated.
A famous case began on 30 January 1962 at a girls' boarding school in Kashasha, in what was then Tanganyika and is now Tanzania. Fits of laughter spread from pupil to pupil, then to nearby villages and other schools. Symptoms lasted from a few hours to 16 days. In all, about 1,000 people were affected and 14 schools were closed before the episode died out about 18 months after it began. Researchers have linked it to the stresses of a period of rapid change after independence.
Scientists sometimes model this kind of social contagion the way they model infections, as something passing through a network of contacts. Rumours and scares can spread in a similar way, with ordinary events reinterpreted as part of the panic.
Coming up in future stories
- The Laughing Epidemic That Closed 14 Schools 1962 · Kashasha, Tanganyika (now Tanzania)
- The Summer Strasbourg Couldn't Stop Dancing July–September 1518 · Strasbourg, Holy Roman Empire (now France)