During the fall of 2012, something odd began happening at two high schools in northeastern Massachusetts. At least two dozen students began to exhibit mysterious hiccuping sounds. By early 2013, the symptoms had died down at North Shore Technical School in Middleton, but at its sister school – Essex Aggie in nearby Danvers – 18 girls were suffering from the bizarre ailment. A survey of students’ symptoms as collected by parents, includes such descriptions as: “Starts as a regular hiccup and then turns into a high pitched yelp,” “Loud, piercing hiccups,” and “Sounds like an exaggerated hiccup.” The State Health Department conducted extensive tests of the school grounds and found air and water samples within normal limits, as were tests for toxic substances that could cause neurological problems, such as mercury.

So what caused this baffling outbreak? A study of nine of the students’ medical records, considered and eliminated every possible cause but one: mass hysteria. Its more common scientific names are mass psychogenic illness or conversion disorder. The condition involves the converting of psychological distress into physical symptoms. A survey of mass hysteria outbreaks throughout history reveals that they most commonly occur in schools and involve adolescent girls. While no trigger was ever identified in Massachusetts, it was almost certainly some type of stress.

While the Health Department used the word ‘hiccups’ to describe the outbreak, the students were not experiencing hiccups, but what neurologists refer to as vocal tics. In this instance, most of those affected had chronic vocal tics, which is defined as lasting over a year. This rare condition primarily affects young boys. It is extremely unusual to have an outbreak in 18 teenage girls at the same school within a relatively short time span. The odds of this happening are astronomical. In fact, there is only one similar case in American history: the outbreak at LeRoy High School in Western New York during 2011-12, where over a dozen girls and one boy were affected by vocal tics. Tests of the school and the surrounding area, also proved negative, including air, water, and soil samples. Neurologists treating the girls concluded that their symptoms were spread by social media: Youtube, Facebook, Twitter. As the students in Massachusetts were never interviewed as part of a formal study, we are left to speculate as to the trigger, but given the eerie similarities between the two cases, it would not be surprising to find that social media also played a role. Exactly how it works, is unknown, but it appears to amplify existing tensions and stresses that are so common in adolescent schoolchildren.

The only way to better understand these and other outbreaks of psychogenic illness, is to study them in greater depth, but unfortunately, this is not happening. In the LeRoy outbreak, the New York State Health Department had initially refused to release the diagnosis of mass hysteria for several months until January 2012. In Massachusetts, the Health Department’s medical records review that had eliminated every possible cause but mass hysteria, was never released to the public and never appeared in the Health Department’s final report on the outbreak which was released on November 20, 2014. In fact, nowhere in the report did it even mention the words “mass psychogenic illness.” The likely reason for this is the stigma that is often attached to the diagnosis of mass hysteria, even though the leading authority on the subject, British psychiatrist Simon Wessely, is fond of noting that it is not a disorder but a stress response. Those wishing to learn more on the Massachusetts outbreak, can read my study in May 2016 issue of the Journal of the Royal Society of Medicine. It is based on over one thousand Freedom of Information documents. If the history of science teaches us anything, it is that transparency in dealing with public health matters, is always the best policy.