The epidemic that struck the staff of London's old Royal Free Hospital in 1955 was explosive. Within two weeks, the number leaped from five victims to more than 100. The hospital had to be closed to new patients on July 25, and it stayed shut until October. More than 300 cases were recorded, two-thirds of them severe enough to require hospital treatment. Virtually all of the physical symptoms fitted the concept of an infectious disease: headache, sore throat, malaise, dizziness, nausea and vomiting, diarrhea. Since the Royal Free's expert microbiologists could find no bacteria to blame, they concluded that the cause of the outbreak was an even smaller and more elusive germ, an unidentified virus.
Not so, say two psychiatrists who have combed the voluminous records of the Royal Free outbreak and more than a dozen like it that have been reported recently. In fact, they suggest in the British Medical Journal, the outbreak was a classic case of mass hysteria. It falls into the same category as the dancing manias of Germany in the Middle Ages or the Neapolitans' tarantella.
Laboratory Logic. Why did it take so long for the diagnosis to be made? Mainly because in the '50s no one expected to see such behavior in developed countries, least of all among sophisticated personnel in a great medical center. In an age of scientific medicine, it seemed much more logical to send specimens to the laboratory and put them under the microscope.
The Royal Free's doctors had good reason for beginning with a strictly medical approach. Some of the victims' symptoms included loss of feeling in the extremities and severe muscle weakness. In a few cases with paralysis, poliomyelitis was suspected—reasonably enough, since there was an outbreak of polio in the area. The eventual consensus was that some form of encephalitis had struck.
Still, Drs. Colin P. McEvedy and Alfred Beard suggest that the Royal Free doctors were wrong in concentrating on their tongue depressors and throat swabs and ignoring the emotional factors. For one thing, none of the victims died or even had a high fever, a most unlikely finding in an infectious epidemic. The known presence of polio in the area, say the psychiatrists, had made the hospital population fearful. After that, "anxiety must have been self-propagating and mass hysteria the major factor at work."
No Slur. What virtually clinches their explanation, they feel, is the distribution of the malady within the hospital. Among 600 men, only five cases were rated as severe, for an attack rate of 0.8%, whereas among 1,760 women there were 193, or 11%. Most of the victims were nurses under 30. This fits the pattern of similar epidemics, including one at Los Angeles County Hospital in which 78% of the victims were nurses. Other outbreaks have been in girls' schools and a school for midwives.