Social networkers show side effects
The first victim was 16-year-old cheerleader Lori Brownell. A student at LeRoy High School in New York, Lori passed out at a school dance late last year and woke up with symptoms resembling Tourette's Syndrome, including shaking uncontrollably and slurred speech.
In the months that followed more girls from the same school, all cheerleaders, have begun to suffer from facial tics and shaking.
By March this year, 16 cheerleaders and one boy at the school had developed the sporadic verbal outbursts and twitching that Lori had begun to endure months earlier. Some have since made full recoveries, others are still displaying symptoms.
The students have been tested for poisoning, and air and soil samples were taken from the school.
But all the tests returned normal, and doctors now say the students are most likely suffering from conversion disorder - a type of mass hysteria. Dr Robert Bartholomew, a sociologist and author who has been researching mass hysteria for more than 30 years, says similar scenes to the LeRoy school case will become more common in Australia.
The rapid growth of social media makes it difficult to isolate people with conversion disorder, for example in a classroom, he says.
"Hysteria is spread by sight and sound, but these days social media is an extension of your eyes and ears.
"Before, you could contain the situation to a certain area, like a classroom or factory.
"But if someone is posting videos and updates of what is happening or what they're experiencing on social media, even though people in the wider community are not there with the sufferers they may start to think they've been affected in some way."
As The New York Times reported of the case: "The story took off quickly, not just on the local and national news but on Facebook and autism blogs and sites devoted to mental health and environmental issues."
Mass hysteria comes in two forms, Dr Bartholomew says. The first is triggered by an extreme and sudden exposure to stress such as the September 11 terrorist attacks.
"Suddenly people around the world would smell a weird odour or hear a loud bang and there was a group consensus it must be a terrorist attack," he says. "That has been a very common scenario in the past 20 or 30 years."
The second kind is contained to smaller groups of people in the same area.
Teachers see this occur when a child in a classroom says they feel sick, leading to other classmates claiming they feel sick too, Dr Bartholomew says.
Traditionally such cases were self-contained, but he said social media meant symptoms could now spread more widely.
"The cheerleaders suffering from these symptoms in New York started posting about it on social media, which is seen by people in other classrooms and in the wider community," he says. "People start to get worried, they start looking up the symptoms on the internet and on social media, and now a nurse in the community is suffering from the same symptoms as the cheerleaders too."
Although television, radio and print media had traditionally contributed to the spread of mass scares, Dr Bartholomew says those stories were usually focused on large-scale events and tended to die down after a week.
Once stories such as the case at LeRoy High School hit social media networks, however, they take on a life of their own.
"Social media is evolving quickly and we need to be doing studies on those social networks and how they relate to the potential spread of illness," he says.
Dr Bartholomew claims some health authorities were reluctant to publicly cite mass hysteria as the cause in such cases.
"I think the big problem is the stigma attached to it," he says.
"If you say someone has an anxiety disorder, it is not a compliment. The victims feel like they are being told that it's all in their heads, but actually it's not all in their heads. The symptoms are there and they are going through something very real."
Dr Jim Buttery, an infectious diseases paediatrician with Monash Medical Centre and the Royal Children's Hospital in Melbourne, has seen similar symptoms occur. described the case in the Medical Journal of Australia he describes one case where children receiving vaccinations against cervical cancer displayed symptoms of what he believes may have been hysteria. He says the potential public health implications of such incidents could be damaging.
Five years ago, 720 girls received the cervical cancer vaccine at a metropolitan school in Melbourne. Within two hours of vaccination, 26 girls reported symptoms including dizziness, weakness and palpitations. Tests of the girls found no basis for their symptoms and all of the girls recovered.
It was likely they had experienced a case of mass hysteria. But Dr Buttery says if people believed the girls had experienced adverse reactions to the vaccines, they could be deterred from getting the vaccines themselves and the girls affected may be reluctant to go back and get the full three doses.
"Conversion disorder tends to occur in waves of direct visualisation initially, but if it was taken up at community level thanks to social media, I think it's very reasonable to hypothesise that the social impact could be more rapid and widespread than previously," Dr Buttery says.
He believes more research is needed into the possible impact of social media on public health.