Mass Psychogenic Illness

This essay is reproduced here as it appeared in the print edition of the original Science for the People magazine. These web-formatted archives are preserved complete with typographical errors and available for reference and educational and activist use. Scanned PDFs of the back issues can be browsed by headline at the website for the 2014 SftP conference held at UMass-Amherst. For more information or to support the project, email

Mass Psychogenic Illness

by Laurie Case

‘Science for the People’ Vol. 12, No. 2, March-April 1980, p. 18–19

Laurie Case is a freelance writer involved in the health care community in the Bay Area.

Among the workers in California’s “Silicon Valley” a variety of symptoms have been noted which seem to affect both individual workers and groups of workers at once and which often tend to disappear over the weekend, only to resurface Monday morning. These include nose bleeds, skin rashes, dizziness, headaches, fainting, and nausea. When researchers have investigated workplaces but have been unable to find persuasive evidence of toxic substances or other officially recognized environmental health hazards, they have revived and renamed an age old diagnosis, Mass Hysteria, and labelled these outbreaks “Mass Psychogenic Illness.” 

Who Is Most Likely to be Labelled Psychogenically Ill? 

Curiously, 90 percent of the workers said to exhibit mass psychogenic illness are women. Many of them do assemblyline work in the burgeoning American electronics industry which employs more than a quarter of the workforce in California’s Santa Clara County.1 Seventy-five percent of all electronics production workers are women, and some 40 percent of these women are Third World, mostly of Spanish or Asian descent. 

In this industry, where companies compete to increase production, speed and dexterity are at a premium, the work is extremely stressful and painstaking, and little is known about the toxic effects of the chemicals used. At $3.28 per hour, the average starting wage is so low that women who head households often need welfare subsidies to survive. (These payments constitute an indirect subsidization of private industry by government.) Until recently, working conditions for assemblers have not been a concern of the industry. 

Sexism and Psychogenic Illness 

Taking their cues from Freud, psychologists have traditionally argued that women are prone to hysteria. Michael Colligan, a clinical psychologist for the National Institute for Occupational Safety and Health (NIOSH) has modernized this argument for industry, holding that the sex bias of mass psychogenic illness reflects traditional sex roles which allow women to express psychological stresses and emotions, but require men to “bear down and suffer.” The point, however, is that the predominantly female electronics assembly workforce is subjected to potentially hazardous and stressful work conditions. The work is carried out in plants that are often poorly ventilated, and the workers are exposed to hundreds of harmful chemicals: organic solvents such as TCE and chloroform; lead, arsenic and other metals; caustic acids; exotic gases such as arsine and phosphine; polychlorinated biphenyls (PCB’s), epoxy resins and numerous other substances. 

The work these women do is not only low paying; it is incredibly monotonous with little opportunity for creativity and advancement. They are constantly pressured by speed-ups, excessive demands for overtime and infrequent breaks. They are kept in the dark about the potential toxic effects of the chemical agents and processes with which they work. Importantly, they are mostly unorganized and thus lack the more usual channels for effecting changes in workplace conditions. When these factors are considered in combination with exposure to potentially toxic chemicals, the unexplained outbreaks of illness become understandable. 

Is Mass Psychogenic Illness Diagnosed Scientifically? 

At 8 a.m. on May 10, 1979, four female electronics workers at Verbatim, a manufacturer of computer parts, began feeling dizzy, then severely nauseous. A hazy layer of air was seen hovering above their work station. The entire building was ordered evacuated, for many workers were experiencing similar symptoms and 35 were taken to a local medical clinic, where they were examined and promptly released. Occupational Safety and Health Administration (OSHA) representatives and a doctor conducted a walk-through inspection of the plant, and by noon management declared that full production could be resumed because there was no danger from toxic compounds. At 1:30 p.m. the first environmental sampling confirmed management’s as yet unfounded conclusion. In a follow-up report issued two weeks later, an investigating OSHA physician, Linda Garb, summarized the incident at Verbatim:

It is my opinion that the most likely explanation… is mass psychogenic illness. Neither the industrial hygiene nor lab tests provide evidence which could otherwise explain the incident.

Colligan, Smith and Hurrel reported at a 1979 NIOSH conference on occupational stress that a diagnosis of mass psychogenic illness is “arrived at by a process of elimination and is based on impressionistic evidence.” In other words, when no officially sanctioned set of physical conditions appears to be violated, researchers resort to the label mass psychogenic illness. Given the time lag between eruptions of illness and inspections, though, physical conditions are hard to assess with any accuracy; and even where it can be established that no violations occurred, OSHA guidelines are often inadequate. That is, a workplace might conform to OSHA standards and still be hazardous to its employees’ health. For example, the toxicity of combined chemical effects (known as synergism) is poorly understood. 

The Real Dangers of Mass Psychogenic Illness 

The illnesses these women experience are indeed real and they merit careful scientific attention. The label mass psychogenic directs scientists to look to workers’ psyches for causes and solutions, meanwhile ignoring potential physical workplace hazards and stressful conditions. It allows scientists to translate their investigative inadequacies into “respectable” jargon and lets industry off the hook. Poor investigative procedures and jargon must never be allowed to masquerade as science. They must not be allowed to sidetrack efforts to discover critical environmental causes of the physical symptoms these assemblers display; workers must not be blamed by labelling as “hysteria” their physical reactions to very real stress-producing conditions. In short, the concept of mass psychogenic illness must not be allowed to divert attention away from the need to develop better methods for detecting and rectifying the effects of toxic substances, of the kinds of stressful working conditions these women encounter daily and of their synergistic interactions. 

Implications of Research on Mass Psychogenic Illness 

Research identifying the mental correlates of occupational disease has already generated some disturbing products. NIOSH’s recently developed personality-trait questionnaire to identify the “hysteria prone worker” is one such product. If adopted, this sort of questionnaire (assuming it works with any reliability) allows industry to become more discriminating in its personnel decisions, meanwhile neglecting the toxic environments of its workers. (See Jon Beckwith’s article in this issue for a discussion of medical research efforts to identify genetic “propensities” for occupational diseases.) These developments are dangerous because they shift the burden of hazardous work onto the industrial worker, thus creating the potential for denying protection, treatment, and compensation for job-related illnesses. Furthermore, they create the potential weapons for eliminating “unsuitable” and “undesirable” job applicants and employees. Ultimately they give industry a long term license to endanger the lives of workers

>> Back to Vol. 12, No. 2 <<


Colligan, Michael J., & Smith, Michael J., “A Methodological Approach for Evaluating Outbreaks of Mass Psychogenic Illness in Industry,” Journal of Occupational Medicine 20. no. 6, June 1978.

Elesh, Elva, Moseley, C., Pryor, P., & Singal, M., “Mass Psychogenic Illness in Industry — NIOSH’s Role,” paper presented at the American Industrial Hygiene Conference symposium on “The Diagnosis and Amelioration of Mass Psychogenic Illness,” May 20- June 1, 1979, Chicago, Ill.

Scolnick, Barbara & Wegman, D.H., unpublished review of the background and current status of the “GRC Sickness” at the University of Massachusetts, Amherst. Authors are associated with Occupational Health Program, Harvard School of Public Health.

  1. *See also Mandy Hawes, “Dying for a Job,” this issue, for further discussion of electronics workers.