10 Strangest Mass Hysterias

West Bank Fainting Epidemic (1983)
A Palestinian schoolgirl cries after Israeli forces use force to disperse a student protest in 2011. In 1983, both sides accused the other of deliberately trying to poison schoolchildren in the West Bank. The case was deemed one of mass hysteria. AZEM BADER/AFP/Getty Images

In the spring of 1983, nearly 1,000 young Arabs in the West Bank suddenly became ill with a mysterious ailment characterized by symptoms like headache, dizziness, blurred vision, abdominal pain, weakness and fainting. Seventy percent of the patients were schoolgirls 12 to 17 years old [source: Centers for Disease Control and Prevention].

When some of the early victims said they smelled a strange odor reminiscent of rotten eggs in their classroom before falling ill, Palestinian leaders accused the Israelis of using chemical warfare to drive away the Arabs; some even claimed it was to sterilize Arab females. Israeli officials, in turn, said Palestinians were using chemicals on their own people to stir up trouble [sources: Shipler].

After schools closed in the West Bank, no additional illnesses occurred. And no trace of chemical residue was found in any of the buildings. Health authorities determined that the initial group to fall ill may have been affected by the smell of low levels of hydrogen sulfide gas escaping from a latrine. But the bulk of the sufferers became ill because of psychological factors, namely stress and anxiety, which were likely caused or heightened by news reports suggesting a toxic gas was the culprit.