Doctors treating the strange case of nearly 20 teenagers with a twitching disorder in upstate New York say the symptoms may be spreading faster through the girls' own use of Facebook and other forms of social media.
Experts have diagnosed the problem as a form of mass hysteria in which an individual, usually a young woman, becomes ill during a period of stress, and others in the same community, school or workplace begin to show the same physical symptoms.
Last fall, several girls in the small town of LeRoy, N.Y., began complaining of involuntary facial and body twitching that resembled Tourette's syndrome. Since then, a dozen girls from 13 years to 18 years old have been affected, as well as one boy.
In the past week, four new cases have been presented for a total of 19 patients, according to Dr. Laszlo Mechtler, chief of neurology at the Dent Neurologic Institute in Buffalo. MSNBC has reported that a 36 year-old woman in the town has also come down with the twitching.
"When one has a symptom, it can be reinforced and magnified with other individuals with similar symptoms," said Mechtler. "That's what's going on with these girls. They are in a segregated small rural town in New York state. They are a cohesive group. And this wildfire of symptoms takes control."
Mechtler, who has treated about half of the patients, says some of the girls are best friends, others know each other from the soccer team or cheerleading squad. Mechtler and other doctors have diagnosed the problem as psychogenic movement disorder, which is a form of conversion disorder.
That means that the brain is actually subconsciously mimicking the twitching felt by others. While the exact neurologic pathway is still unclear, researchers believe the common factor is stress and anxiety. Mechtler emphasized that the girls are not faking their twitching.
Some parents have rejected that diagnosis and believe that some kind of environmental toxin is to blame. They've asked environmental activist Erin Brockovich to investigate a spill of chemicals in the town that occurred more than 40 years ago.
State health officials say the spill was cleaned up, and that they've performed extensive testing for both chemicals and other toxins, such as mold, in the school. Doctors have also tested the girls for traces of chemicals. All came up negative.
Mass hysteria has a long history that some believe may have been responsible for the reports of demonic possession that rocked Salem, Mass., in the 1600s and led to the infamous Salem witch trials. More recently, 600 Mexican schoolgirls came down with nausea in 2007, a case also diagnosed as conversion disorder.
There have also been similar school outbreaks in Tanzania, Portugal, Brunei, England and the West Bank in the past 40 years. But the Internet and social media have changed how the disease spreads, especially in the New York.
Several of the teenagers have posted videos of themselves on YouTube asking people for help in diagnosing their condition. They're also sharing their symptoms on Facebook.
When Dr. David G. Lichter saw some of the teens' videos last weekend, he was astounded at how similar the ticks were.
"It's remarkable to see how one individual posts something, and then the next person posts something -- not only are the movements bizarre and not consistent with known movement disorders, but it's the same kind of movements," said Lichter, professor of neurology at the University of Buffalo who has treated several patients as well. "This mimicry goes on with Facebook or YouTube exposure.
This is the modern way that symptomology could be spread."
Lichter said that the longer parents wait to get their children treated -- which usually involves psychotherapy and medications to relieve stress or anxiety -- the longer the disorder will last. He said that some girls are already improving with treatment.
Researchers at the National Institutes of Health in Bethesda, Md., are trying to figure out how conversion disorder works. They've been running a clinical trial since 2007 that has focused on genes that could be responsible for controlling anxiety levels, as well as social factors such as family stresses and depression, according to Dr. Mark Hallett, chief of the human motor control division at the National Institute of Neurologic Disorders and Stroke.
"It is not going to be a simple explanation and it may be multi-factorial," Hallett told Discovery News. The causes "could be biological, psychological or social."