mass hysteria

noun, Psychology
1.
a condition affecting a group of persons, characterized by excitement or anxiety, irrational behavior or beliefs, or inexplicable symptoms of illness.
Also called epidemic hysteria.
Origin
1930-35
mass hysteria in Medicine

mass hysteria n.

  1. Spontaneous, en masse development of identical physical or emotional symptoms among a group of individuals, as in a classroom of schoolchildren.

  2. A socially contagious frenzy of irrational behavior in a group of people as a reaction to an event.