Mass psychogenic illness (MPI) or mass hysteria is not a rare phenomenon around all corners of the world. It has been defined as a group of physical signs and symptoms that suggest the presence of organic illness but without any clinical and laboratory evidence of disease [1, 2]. Since the year 1374, it has been documented for more than 600 years in a variety of culture [3–4], ethnic [5], and religious [6–7] settings.
There is no conclusive evidence about the causes of the illness but psychological factors, environmental factors, different stressors, conflicts, lower level of education, lower socioeconomic status, minority race, and history of abuse or trauma were commonly postulated causes [8, 9]. It is common in rural areas among uneducated people, lower socioeconomic classes, and ethnic minority groups. It is usually seen in girls and teenager groups. The episode prolonged from weeks to months [10, 11].
Evidences from various studies revealed that it commonly affects people who live in groups; at Schools (50%), Town and villages (10%), Factories (29%), family groups (4%). Sometimes it is notified from Nunneries, Boardinghouses, Prisons and Religious institutions [12–14, 15].
Majority of the outbreaks are recognized due to environmental “trigger” such as bad smell, abnormal sound, a suspicious looking substance, or something else that makes member of the cohesive group exposed to a danger [13]. It is typically begins when an individual with index case becomes ill hysterically during a period of stress followed by multiple people experiencing of the same symptoms [14–15]. Among the total reported hospitalized ill students in Bangladesh, 88% complain about consumption of cake with abnormal smell or taste. Among these, 20% of them felt ill by only seeing other ill students in the school [16]. Satanism and evil devil force, punishment by God, due to the presence of toxic chemicals, polluted environment, cold air, and using family planning injection or pills had been discovered around the schools and community members in Ethiopia [16–19].
In Africa evil spirit, witchcraft, Satanism or failures to perform cultural and religious rituals have been mentioned as the causes of the illnesses [5]. Similar finding was reported from Kombolcha of Northern Ethiopia, Derashe of Southern Ethiopia, [17–18]. On the other hand toxic chemicals and environmental pollution have been notified in western setting; India due to toxic fumes [13], these attributions in Africa, lead many victims commonly seek treatment from different religious and traditional healing sites [13–18]. This is also practice in Ethiopia context in which more than half (63.9%) of study participants in Derashe district of Southern Ethiopia reported that they had been visiting traditional healing services, 8.2% had sought treatment from religious services, 75.3% modern health service, 5.1%, all the three treatment sites, namely traditional healers, religious healers and health institutions[18].
It is recognized as a rapid spread of illness, signs and symptoms mainly affecting members of a cohesive group that has been originating from a nervous system disturbance involving excitation, loss, or alteration of function, where by physical complaints that are exhibited unconsciously have no corresponding organic etiology [2].
Common symptoms of mass psychogenic illness reported were nausea, dizziness, fainting, headache, abdominal pain, hyperventilation, cough, fatigue, drowsiness, weakness, watery eyes, chest pain, vomiting, communication difficulties, laughing, and fainting were common in African settings [8, 10, 15–17].
Mass psychogenic out breaks were reported in different African settings including Ethiopia [14–16]. Similar outbreaks of MPI were also reported in different Ethiopian settings; Bati, Kombolcha, Derashe, and Gondar [8–17–19]. Despite the difference in culture, religion and age range, the clinical presentation of the cases during an episode were similarly reported. All reported incidents brought a common intense of a public and community terror to the extent of collapsing school and occupational activities. Tough there is an increase in awareness among health professionals; it is still under considered, under reported and still causing significant health and social problems in the country.
However, epidemics of hysteria is under reported or not studied well across the country. Besides, none was conducted in the study region in Tigray region, Northern Ethiopia. The incident was happened for the first time in Eastern parts of Tigray, Northern Ethiopia in Erop district. Its clinical characteristics, community perception about the root cause, treatment and its prevention mechanism were not known. The aim of the study was to assess the episode of mass psychogenic illness in Erop districts, Tigray region, Northern Ethiopia and to guide interventions and improve understanding and recognition of similar events for the future.