Definition:
Mass hysteria is a form of groupthink, in which several people with something in common begin to think in the same way. In mass hysteria, the group members all develop a common fear that often spirals into a panic. The group members feed off each other's emotional reactions, causing the panic to escalate.
Some riots, witch hunts and other events can be linked to mass hysteria. The radio broadcast War of the Worlds and the TV movie Without Warning both spawned outbreaks of mass hysteria.
