The phenomenon known as mass psychogenic illness or epidemic or mass hysteria is a strange one that has cropped up from time to time over the centuries. Outbreaks occur among closed groups of people, as in schools, factories or hospitals. Physiological processes which induce pain or distress in a few individuals apparently spread to induce psychogenic disturbances in large numbers of people with whom they are in close contact. Among the factors involved in such disturbances are considered to be a natural fear of infectious epidemics and, more recently, a justified fear of mysterious terrorist activities, which spread the symptoms from the physiological into the psychological sphere.
The New England Journal of Medicine for January 13 carries a report of such an epidemic which occurred in a high school in Tennessee. The news media reported that students and staff were experiencing symptoms believed to denote exposure to some sort of toxic fumes. The affair started when a petroleum-like odour was noticed in a classroom and a teacher complained of headache, nausea, shortness of breath and dizziness. When several students complained of experiencing the same symptoms the entire school was evacuated. During hospital observation of 38 individuals supposedly affected, no explanation for their symptoms could be discovered.
Four days later the school reopened, but next day there were several more complaints, resulting in a further closure of the premises. Environmental sampling was carried out but revealed no source of toxic substances. On questioning, many of the sufferers said that they noted a strange smell in the school at the start of the epidemic, but descriptions of it were not consistent. The episode incurred enormous costs both in terms of study time lost and expenses of expert advisers and public services.
The phenomenon was concluded to be psychogenic in nature, with transmission from individual to individual under stress, intensified by the interest taken in the affair by the mass media of communication. Attitudes were made worse if the investigators mentioned the phrase "mass hysteria", one calculated to provoke outbursts of indignation in most people. It is feared that the incidence of such outbreaks may increase as justifiable fears regarding bioterrorist activities spread in the civilised world.