In 1962, a contagious outbreak of uncontrollable laughter began in a girls’ school in Tanganyika (now Tanzania). The laughter spread rapidly to nearby communities, lasting from a few hours to several weeks for some individuals.
Schools closed as hundreds were affected. No physical cause was found, and the event is considered an example of mass sociogenic illness. Stress and anxiety from local social conditions likely contributed to this unusual outbreak of shared psychological symptoms.