Mass Psychogenic Illness / Mass Hysteria / Mass Sociogenic illness / Epidemic Outbreak / Mystery Illness / Multiple Occurrences of Unexplained Symptoms

Mass Psychogenic Illness is commonly defined as “the collective occurrence of physical symptoms and related beliefs among two or more persons in the absence of an identifiable pathogen.”1 It is also most commonly known as mass hysteria. Aihwa Ong views MPI as a strategy of resistance as she writes that “they are acts of rebellion, symbolising what cannot be spoken directly, calling for a renegotiation of obligations between the management and workers.”

MPI is often seen as a problem to all individuals in the vicinity of the incidents. The question is why is it a problem and to whom. Joseph Mcgrath claims that the problem of MPI for affected individuals is that symptoms “are a source of discomfort”. The problem will only cease to be a problem if the symptoms stop and the negative after effects are limited. Affected individuals also pose a danger to themselves and other non-affected individuals within the vicinity. Setting managers see MPI as a problem because it is costly and disruptive to production or other settings. The problem will cease to be a problem if there is cessation of symptoms and further spreading of symptoms. Additionally if no causal agents such as toxic substances for which they are responsible for are found, the problem of the manager will also cease to exist. A manager in an American plant was worried he would get in trouble with headquarters, “I can’t tell them that 8,000 hours of work were lost because somebody saw a ghost!”3

For researchers, physicians and epidemiologists, “the problem does not stop being a problem until they can collectively develop and verify an explanation for the occurrence.’MPI can also be viewed as indication of distress levels. According to Jerome E. Singer from the Uniformed Services School of Medicine, “we regard illness in response to a toxin or something in the air as unhealthy, but perfectly normal; we don’t think it’s strange that somebody becomes ill when they breathe a substance that they shouldn’t be breathing.”4 

MPI does not present itself in one form. According to W. H. Phoon from the Singaporean Ministry of Labour, who presents six case studies from Singapore maintains that there are three main modes of presentation of MPI: Hysterical seizures, trance states, frightened spells.

Hysterical seizures: Screaming, struggling fiercely and general violence.

Trance states: While being violent, or before becoming violent, a worker would suddenly speak as though she was someone else, and claim that a jin or spirit was speaking through her.

Frightened spells: The affected workers only expressed a feeling of unexplained fear, and might complain of feeling cold, numb or dizzy.5

As proposed by several researchers, these are the parameters that indicate symptoms of MPI.

Simon Wessley states that there are four premises for mass hysteria:

  • First, it is an outbreak of abnormal illness behaviour that cannot be explained by physical disease.

  • Secondly, it affects people who would not normally behave in this fashion.

  • Thirdly, it excludes symptoms deliberately provoked in groups gathered for that purpose, as occurs in many charismatic sects.

  • Fourthly, it excludes collective manifestations used to obtain a state of satisfaction unavailable singly, such as fads, crazes and riots.

  • Finally, the link between the participants must not be coincidental.6

According to Francois Sirois, there are five types of epidemic outbreaks:

  • Explosive type - Symptoms appear rapidly, involving at once many people and are usually short lived. A tension discharge phenomenon in a closed group. The benign and self limited presentation is often given a superficial

  • Explosive with identifiable prodrome stage - Isolated cases are first detected. There is a gradual build up of tension and the explosive outbreak follows. Index cases are probably perceived either as threatening to the group or used to carry and express some other shared conflicts.

  • Cumulative - Less than 10 persons are involved and the transmission of symptoms occurs over a longer period of time-two weeks to a month-as a slow chain reaction.

  • Rebound - A handful of cases appear rapidly and in the following days a more important second wave of people become symptomatic. The outbreaks last a month and involve larger groups of 30.

  • Large diffuse - it appears in communities, rural areas or towns. It is not restricted to specific groups. A fairly large number of people of both sexes and all stages could be involved.7

Outbreaks usually occur in three stages: prodrome, epidemic moment and rebound.

Francois Sirois has also suggested that these three stages should be studied with different frameworks.

  1. The prodrome may be examined with a psychodynamic approach since it deals mainly with the underlying fantasies behind and before the outbreak.

  2. The epidemic moment is best served by an epidemiological approach since it concerns the clinical aspects of the distribution of the outbreak.

  3. The rebound can be studied with a social historical approach because it deals with the contextual elements surrounding the attacks. This is especially important to explain all that goes on in the maintenance of the episode from relapses to the social given to the outbreaks.8

Michael J. Colligan and Lawrence R. Murphy list specific qualities of the work environment that supposedly precipitate the outbreaks.

  • Boredom from a low status, highly repetitive and routine job.

  • Work pressure from having to increase output/production.

  • Physical stressors that relate to various physical characteristics of the work environment.

  • Labour-Management relations that are poor can range from strict dress codes to supervisory techniques.

  • Lack of Communication due to the compounding of stress  from noise of machines and impairment of communication.

  • The Dynamics of Contagion could be classified under contagion or convergence. Colligan and Murphy believe that convergence where group members of a certain situation develop common affects or response patterns independent from one another seems to be more likely the mode of spreading outbreaks. Contagion is where a single individual acts as stimulus for the imitative act of others.9

I try to use these frameworks provided by these researchers to understand an incident described by former factory worker, Zainab Mahmood. Only audio was recorded so there is no image for this interview. In an attempt to experiment with one aspect of the documentary form, I transcribed the interview and placed the text on black frames - essentially transforming the transcript into subtitles. These subtitles present the possibiliy of images to emerge but at the moment I will keep the frames black.



Here I attempt to determine the incident through the different categorisations metioned above.

  • Affected individual seemed to be in a state of trance and caused other workers to experience fainting.

  • The situation seems to match everything that Simon Wessley proposes.

  • This case is probably considered the explosive with identifiable prodrome type?

Prodrome: Lady’s pocket is torn from uniform. Hears voices in the toilet and battles entities as she tries to leave the toilet. She sees black figures.

Epidemic moment: Lady comes back from toilet and starts cackling
Factory workers are affected which results in screaming and fainting

Rebound: Workers were terminated which means that there was a low chance of recurrence?  I cannot and will not speculate  the specific qualities of the outbreak because this would mean that I would have to assume certain things. I am not sure how the affected individual felt during this occurrence.  

Coligan and Murphy warn of the danger of MPI as a diagnosis as this may lead to abuse by management in favour of the continuing production. The reason for this is because management might see MPI as an excuse to dismiss other environmental factors that could have caused workers to react collectively.

“Mass Psychogenic Illness is a political as well as behavioural phenomenon–neither employees nor management appear well equipped to deal with the concept of psychogenic illness. Too often, affected individuals are “blamed”, eg,. The illness is “all in their heads.” This is paradoxical because the data suggest that MPI occurs in normal individuals in response to stressful organizational/work environment factors, not personality factors. Also since MPI has now been defined, it is open to abuse.”10

Another common thread in the articles is that researchers tend to repeat that MPI is real. How does one define “real” in terms of a psychogenic condition? Why was it an important point for researchers to reiterate as they spoke about MPI? 

Jerome E Singer, Carlene S. Baum, Andrew Baum and Brenda D. Thew
“MPI, as with any other psychosomatic illness, is a real illness. That there is an economic loss is clear, but it should also be noted that the victims of it are ill- the lack of a specific pathogen to be held accountable does not mitigate their real distress. It would only compound their illness to imply that because the instigating factors are psychological their illness is “only in their heads”11


Michael J. Colligan and Lawrence R. Murphy
  “To describe an illness as psychogenic does not detract from      the  seriousness of the illness–the illness is real and the      workers are sick.”12

“MPI reflects one consequence of not attending to or ignoring the basic needs of the worker as an individual. Improving the quality of working life is rightly becoming a basic tenet of organizational practice and MPI serves to highlight its importance.”13

“The most important aspect is that tensions are unspoken or untold. Epidemic hysteria is thus used by society to displace or camouflage the real conflicts. Therefore, the outbreaks become the focus where both the individual and social conflicts are superimposed upon each other and cannot be distinguished insofar as both are repressed out of consciousness and become identical in the Unconscious.”14

“A precipitating event of some sort mobilizes individual fantasies which are shared. The fear and anxiety then produced are equaled at a social level with hardly perceived context of social uncertainty for which the outbreaks become a latent solution.”15

“There is a mirroring of the social conflict in the reality and the individual conflict in the fantasy, and the outbreak acquires the value of an unconscious symbolic solution for the social situation.”16

There is also wonder why in Singapore and Malaysia such incidents often occur amongst Malay-Muslim women. Having considered this part of the research, the researcher will  present to you quotes that attempt to provide “answers” for this question.

Aihwa Ong raises the question of morality and gender roles that have been enforced on women from the community.

“In Malay culture, men and women in public contact must define the situation in nonsexual terms. It is particularly incumbent upon young women to conduct themselves with circumspection and to diffuse sexual tension. However, the modern factory is an arena constituted by a sexual division of labor and constant male surveillance of nubile women in a close, daily context.”17

“Malay women became alienated not only from the products of their labor but also experienced new forms of psychic alienation. Their intrusion into economic spaces outside the home and village was experienced as a moral disorder, symbolized by filth and dangerous sexuality. Some workers called for increased "discipline," others for Islamic classes on factory premises to regulate interactions (including dating) between male and female workers. Thus, spirit imagery gave symbolic configuration to the workers' fear and protest over social conditions in the factories. However, these inchoate signs of moral and social chaos were routinely recast by management into an idiom of sickness.”18

She also brings to attention that the worldview of the community becomes challenged by the management of industrial settings.

“The nonrecognition of social obligations to workers lies at the center of differences in worldview between Malay workers and the foreign management. By treating the signs and symptoms of disease as "things-in-themselves", the biomedical model freed managers from any moral debt owed the workers. Furthermore, corporate adoption of spirit idiom stigmatized spirit victims, thereby ruling out any serious consideration of their needs. Afflicted and "normal" workers alike were made to see that spirit possession was nothing but confusion and delusion, which should be abandoned in a rational worldview.”19

In her description of an outbreak that occured in the factory she worked at, Zainab Mahmood states that management did not dismiss the world view of the workers but instead accused factory workers of “releasing spirits” in the factory. Such accusations indicate that management’s adoption of spirit idiom can also be weaponized to provide a basis for action against workers. In this case, management did not need the diagnosis of MPI to justify sacking the workers, the manipulation of local beliefs as evidence against the workers was enough. Here the worldview of the worker is not challenged as being irrational, instead the worker’s morality is the issue - the implication being that the worker willfully caused trouble.

W. H. Phoon also attempts to provide explanation on this matter.

“Malay females, especially if from the rural areas, may encounter psychological stress in adapting to an industrial setting. Added to this, they may also have dissatisfaction over certain work conditions and style of management(eg. Strict discipline). But because of their upbringing, it is against their nature to openly rebel. Direct confrontation with authorities would bring about social disapproval, It is also possible that monotonous work would leave them much time to “brood over” any unhappiness they may experience.”20

“Living things have a ”vital force” which they call semangat which plays an important part in maintaining health. Its presence in the body is believed to exert force externally, preventing evil spirits(hantus) from acting on the body. The hantus are believed to be ubiquitous but invisible, and it is only when the force of the semangat is weakened, that spirits can gain entry into the body.”21

“It is thus postulated that because of internal conflict generated by unhappiness and the inability to self express or vocalize their unhappiness, for fear of social disapproval, the Malay women react by mass hysteria, ie., it is used as a ‘safety valve’. Because of the traditional belief in spirit possession, such behaviour, far from being condemned, is accepted without social disapproval.”22

Singer, Baum, Baum and Thew point out that “susceptibility to MPI does not seem to be a function of race per se. Because individuals are most likely to compare themselves to similar others, social comparison theory would predict that an outbreak of MPI in an ethnically diverse setting would tend to be concentrated in one ethnic group.”23

One tends to notice that MPI can take place in any country or culture but always takes shape in a local context. MPI integrates locality in its presentation. MPI in the factories is a globalised product of industrialisation and “productive” discipline.

The question is why MPI occurs amongst certain workers and not to everyone. What is the bridging factor amongst workers who are affected? As the demographics of factory workers in Singapore also started to change, one wonders if the new workers also experienced such episodes. I currently have no response to this. However, Aihwa Ong raises the idea that MPI which is the all encompassing term might not be so accurate in describing the spirit possession episodes experienced by the workers.

“Different altered states of consciousness, which variously spring from indigenous understanding of social situations, are reinterpreted in cosmopolitan terms considered universally applicable. In multinational factories located overseas, this ethnotherapeutic model is widely applied and made to seem objective and rational. However, we have seen that such scientific knowledge and practices can display a definite prejudice against the people they are intended to restore to well-being in particular cultural contexts. The reinterpretation of spirit possession may therefore be seen as a shift of locus of patriarchal authority from the bomoh, sanctioned by indigenous religious beliefs, toward professionals sanctioned by scientific training.”24


1. Colligan, M. J., et al. Mass Psychogenic Illness : A Social Psychological Analysis. Hoboken, Taylor and Francis, 1982.
2. Ong, Aihwa. “The Production of Possession: Spirits and the Multinational Corporation in Malaysia.” American Ethnologist, vol. 15, no. 1, 1988.
3. Lim, Linda. Women Workers in Multinational Corporations. 1978.
4. Colligan, M. J., et al. Mass Psychogenic Illness : A Social Psychological Analysis. Hoboken, Taylor and Francis, 1982.
5. Wessely, Simon. “Mass Hysteria: Two Syndromes?” Psychological Medicine, vol. 17, no. 1, 1987.
6-16. Colligan, M. J., et al. Mass Psychogenic Illness : A Social Psychological Analysis. Hoboken, Taylor and Francis, 1982.
17-19. Ong, Aihwa. “The Production of Possession: Spirits and the Multinational Corporation in Malaysia.” American Ethnologist, vol. 15, no. 1, 1988.
20. Interview with Zainab Mahmood conducted by Shaza Ishak, 2023.
21-23. Colligan, M. J., et al. Mass Psychogenic Illness : A Social Psychological Analysis. Hoboken, Taylor and Francis, 1982.
24. Ong, Aihwa. “The Production of Possession: Spirits and the Multinational Corporation in Malaysia.” American Ethnologist, vol. 15, no. 1, 1988.