Mass hysteria, also known as mass psychogenic illness, is a phenomenon where a group of people experience similar physical or psychological symptoms without any identifiable cause. It is a social illness that can spread rapidly through a population, often fueled by social media and the internet.

Mass hysteria can take different forms, and researchers have identified two main types: mass anxiety hysteria and mass motor hysteria. Mass anxiety hysteria is characterized by episodes of acute anxiety that occur mainly in schoolchildren, and the rapid spread is by visual contact. On the other hand, mass motor hysteria is characterized by abnormalities in motor behavior, and it occurs in any age group, with prior tension present. Initial cases can be identified, and the spread is gradual, and the outbreak may be prolonged.

Mass hysteria can be triggered by a variety of factors, including stress, anxiety, fear, and social influence. It is often associated with conversion disorder, a mental health condition that involves physical symptoms prompted by emotional or mental tension.

Some historical and present-day examples of mass hysteria include choreomania, where groups of people across Europe began to dance spontaneously until they dropped from exhaustion, and teenagers having mysterious symptoms after watching an episode of their favorite TV series.

In conclusion, mass hysteria is a phenomenon where a group of people experience similar physical or psychological symptoms without any identifiable cause. It can be triggered by various factors, including stress, anxiety, fear, and social influence.