The Tanganyika Laughter Epidemic
On January 30, 1962, three girls at a boarding school in Kashasha, a village near the western shore of Lake Victoria in what was then Tanganyika, started laughing and couldn't stop.
Within hours, the laughter had spread to 95 of the school's 159 students. It lasted for days. Some girls laughed for a few hours, recovered, and then began again. Others couldn't eat or attend class. The school shut down on March 18 and sent everyone home.
That made it worse. The affected students carried the condition to their home villages. In Nshamba, where several Kashasha students lived, 217 people were struck by laughing fits between April and May. The epidemic spread to Bukoba and other surrounding communities. Schools closed. Businesses were disrupted. By the time the outbreak subsided roughly eighteen months later, it had affected about a thousand people across multiple villages and forced fourteen schools to shut down temporarily.
Despite the name, the epidemic wasn't joyful. Victims also experienced crying, screaming, restlessness, and occasionally aggression. Some reported pain, fainting, and respiratory problems. The fits came and went unpredictably. A person might be fine for days and then collapse into uncontrollable laughter for hours. Medical examinations found no infection, no toxin, and no neurological abnormality.
The most widely accepted explanation is mass psychogenic illness—a phenomenon in which stress or anxiety produces real physical symptoms that spread through social networks, particularly in close-knit communities under pressure. The Kashasha school served girls from villages undergoing rapid social change as Tanganyika prepared for independence from Britain, achieved in December 1961. The students lived under strict boarding conditions with limited control over their daily lives. In that context, mass psychogenic illness—sometimes called mass hysteria—was a physical expression of collective tension.
The episode remains one of the best-documented cases of mass psychogenic illness in history, partly because it was so large and partly because it lasted so long. It affected only school-age children and young adults. No adults in authority positions were ever struck.