The students, almost all of them girls, and mostly friends, began experiencing involuntary jerks and tics. Sometimes their limbs, neck or face would suddenly spasm; other times they would twitch, grunt, or shout. It was strange and troubling behavior, made all the more scary because it had no clear cause.
The students were examined by school nurses and private doctors, officials from the Health Department, the Centers for Disease Control and Prevention, and Columbia University. None could find any biological basis for the symptoms. The school was thoroughly checked for mold, lead, carbon monoxide, and other environmental contaminants; those tests also came back negative .... http://news.discovery.com
