The Arjenyattah epidemic. A mass phenomenon: spread and triggering factors.

A massive epidemic of psychogenic aetiology occurred in three districts of the West Bank over two weeks in March-April, 1983. It affected 949 individuals, 727 (77%) of them adolescent females. The symptoms were not accompanied by positive physical signs or by laboratory findings. The epidemiological pattern was pathognomonic of that of a psychogenic disorder. The initial trigger was probably the odour of H2S escaping from a faulty latrine in the schoolyard of the first affected school. Subsequent spread of the disease was due to psychological and extra-medical factors, including publicity by the mass media. Spread was stopped immediately after closure of schools.