Pokemon Contagion: Photosensitive Epilepsy or Mass Psychogenic Illness?

South Med J. 2001;94(2) 

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Epidemic Hysteria Overview

Hysteria is characterized by the impairment or loss of sensory or motor function for which there is no organic basis.[16,17] The modern name for hysteria is "conversion disorder" (the converting of emotional conflicts and anxiety into physical symptoms). Epidemic hysteria refers to the rapid spread of conversion symptoms and anxiety states. It has several distinct features: lack of plausible organic basis, transient and benign symptoms, appearance in a segregated group, extraordinary stress, rapid onset and recovery, symptoms spread by sight or sound, and dispersion down the age-scale beginning in older or higher-status persons. While often referred to as a diagnosis of exclusion, even before tests are complete, it is possible to render an accurate diagnosis based on the presence of the aforementioned criteria.

Epidemic hysteria is most commonly reported in small, cohesive social units within enclosed settings, such as schools and factories. Wessely[18] identified two types of hysterical reactions in groups: anxiety and motor hysteria. Anxiety hysteria has a rapid onset and recovery period, usually 24 hours, and is precipitated by the sudden perception of a threatening agent, typically a strange odor or rumor of contaminated food. Common symptoms include headache, dizziness, nausea, hyperventilation, and general fatigue. Essentially, they are physiologic reactions to sudden anxiety. There is rarely evidence of extraordinary preexisting group tension before the outbreak. Symptom patterns reflect the effects attributed to the imaginary agent. Stomach pain, nausea, vomiting, and diarrhea are typical of suspected food poisoning cases,[19,20] while instances of suspected toxic gas leaks commonly include headache and dizziness.[21,22]

Students or factory workers who are in close visual or social proximity to the affected group member, or subsequently affected members, are at the highest risk of redefining the situation and attributing the illness symptoms to a plausible odor or agent in the environment. In cases in which authorities do not offer a convincing explanation or are perceived as taking insufficient measures to investigate an incident or eliminate the suspected presence of an imaginary agent, episodes often persist for days or weeks, and in rare instances, months. Most reports involve an identifiable index case, in which the first patient exhibits illness symptoms that are usually highly visible and dramatic.[23] Often, unknown to the group, the index case involves a physical illness such as an epileptic seizure, influenza, or schizophrenia. Symptoms are often spread through line of sight.

Mass motor hysteria incubates more slowly than anxiety hysteria, and it develops in an atmosphere of accumulating long-term group stress. It is prevalent in intolerable social settings, most commonly in schools enforcing extreme disciplinary measures. Symptoms include altered states of consciousness, melodramatic acts of rebellion (histrionics), and psychomotor agitation whereby building anxiety over long periods results in disruptions to the nerves or neurons, triggering temporary bouts of muscle twitching, spasms, and shaking. Symptoms appear gradually and usually take weeks or months to subside.

There have been numerous reports of school and factory episodes of this type in Western countries before the mid-20th century, which correlated with strict educational policies or dehumanizing factory conditions before the rise of unions.[24] Modern-day reports are rare except in non-Western schools and factories, where episodes remain prevalent amid strict capitalist discipline or academic regulation coupled with limited or nonexistent grievance channels.

Mass motor hysteria was common in European convents between the 15th and 19th centuries.[25,26] Outbreaks of demon possession and histrionics frequented those orders imposing the strictest Christian discipline. With no means to redress the male-dominated church hierarchy, disempowered nuns often attributed the presence of evil spirits to a despised local church figure. Lengthy church-sanctioned exorcisms and inquisitions were conducted, often resulting in the authority being executed, imprisoned, or banished. Episodes typically endured for 1 to 3 years, since the repressive conditions continued to be enforced during the adjudication process and engendered a continuation of the nuns' symptoms.

In theory, both motor and anxiety hysteria can be alleviated by removing the stressful agent. This may be easier said than done due to the emotionally charged nature of many outbreaks and the difficulty that is often encountered in convincing skeptical group members. In anxiety hysteria, the key is to persuade those affected that the "toxic" agent has either been eliminated or never existed. Episodes of motor hysteria are frequently interpreted by the affected group to confirm the presence of demonic forces, making it vital to convince group members that the offending "spirits" have been eliminated or appeased.


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