mass hysteria

mass hysteria (uncountable)

1. (psychology) The sociopsychological phenomenon in which a large group of people exhibit the same or similar hysterical symptoms simultaneously.
   • 1949 March 7, “Pyramid Club Craze Sweeps Nation”, in LIFE‎, volume 26, number 10, →ISSN, page 27:

     The new mass hysteria is known as the Pyramid Club and began—like so many other strange and wonderful notions—somewhere under the balmy skies of California.

   • 1974 December, Lewis D. Polk, “Mass Hysteria in an Elementary School”, in Clinical Pediatrics, volume 13, number 12, →DOI, page 1013:

     However, these make no mention of mass hysteria or give any suggestion that hysteria may affect multiple individuals at one time in a special situation.