mass hysteria

noun Psychology.

a condition affecting a group of persons, characterized by excitement or anxiety, irrational behavior or beliefs, or inexplicable symptoms of illness.

Origin of mass hysteria

First recorded in 1930–35

Also called epidemic hysteria.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

mass hysteria in Medicine

Spontaneous, en masse development of identical physical or emotional symptoms among a group of individuals, as in a classroom of schoolchildren.
A socially contagious frenzy of irrational behavior in a group of people as a reaction to an event.