Tanganyika laughter epidemic

An outbreak of contagious laughing that began among schoolgirls near Lake Victoria in Tanganyika in 1962 and spread to nearby villages. Christian F. Hempelmann described it in 2003 as mass psychogenic illness.

In 1962, at a boarding school run by a mission close to Lake Victoria in Tanganyika, three girls began laughing, the Guardian reported in 2007. Wikipedia gives the location as Kashasha village, or close to it, on the western shore of Lake Victoria near the Ugandan border; Tanganyika is now part of Tanzania. Robert Provine (American Scientist, 1996) says it started as a single fit of laughing, at times with crying, among girls aged 12 to 18.

The laughter spread from person to person. Provine writes that it reached neighbouring communities and that schools had to close. The Guardian says closing the school made matters worse, because laughing attacks were then reported in Nshamba, where several of the girls came from. Around 1,000 people across Tanganyika and Uganda were affected, according to the Guardian.

The sources disagree on how long it lasted. Provine says six months; the Guardian says it faded two and a half years after it began.

In a 2003 Chicago Tribune interview, Christian F. Hempelmann described the outbreak as mass psychogenic illness: symptoms that come from the minds of those affected, with no cause in the environment such as a toxin or food poisoning. He said it rests on stress shared across the group and tends to arise among people with little power, a last resort for low-status people to signal that something is wrong, which may be why it is tied more often to women. The Guardian noted in 2007 that bloggers were comparing it with a case in Virginia.