Epidemic Hysteria: A Review of the Published Literature

Epidemic hysteria, known by multiple synonymous terms, including mass hysteria, mass psychogenic illness, and mass sociogenic illness, has been defined as a constellation of symptoms suggestive of organic illness, but without an identifiable cause, that occurs between two or people who share beliefs related to those symptoms (1). Rather than being viewed as a collection of people suffering from individual hysteria (or conversion disorder), epidemic hysteria is instead seen as a social phenomenon involving otherwise healthy people (2). It has been described in humans as very similar to a stampede in the animal world (3, p. 301). It has also been called a culture-bound stress reaction (4), in which two separate mechanisms are at work: an anxiety variant, in which abdominal pain, headache, dizziness, fainting, nausea, and hyperventilation are the most common symptoms, and the motor variant, with common symptoms of hysterical dancing, convulsions, laughing, and pseudoseizures (5, 6). Although it has been proposed that in modern Western society the more primitive motor variant essentially has been replaced in form by the anxiety variant (7), examples of this motor variant continue to be reported (8). Numerous reports of this collective behavioral phenomenon date back to as early as 1374 (9). Over the years, concern about a number of issues—water pollution in Camelford, England (10); the phantom anesthetist of Matoon (11); the invasion from Mars (12); and the Royal Free epidemic of benign myalgic encephalomyelitis (13)—spawned large, diffuse outbreaks of epidemic illness. Such illnesses often occur after some environmental trigger, a significant emergency response to that environmental event, and