Mass psychogenic illness attributed to toxic exposure at a high school

Background: Mass psychogenic illness may be difficult to differentiate from illness caused by bioterrorism, rapidly spreading infection, or toxic subs tances. We investigated symptoms attributed to exposure to toxic gas at a h igh school in Tennessee. Methods: In November 1998, a teacher noticed a "gasoline-like'' smell in he r classroom, and soon thereafter she had a headache, nausea, shortness of b reath, and dizziness. The school was evacuated, and 80 students and 19 staf f members went to the emergency room at the local hospital; 38 persons were hospitalized overnight. Five days later, after the school had reopened, an other 71 persons went to the emergency room. An extensive investigation was performed by several government agencies. Results: We were unable to find a medical or environmental explanation for the reported illnesses. The persons who reported symptoms on the first day came from 36 classrooms scattered throughout the school. The most frequent symptoms (in this group and the group of people who reported symptoms five days later) were headache, dizziness, nausea, and drowsiness. Blood and uri ne specimens showed no evidence of carbon monoxide, volatile organic compou nds, pesticides, polychlorinated biphenyls, paraquat, or mercury. There was no evidence of toxic compounds in the environment. A questionnaire adminis tered a month later showed that the reported symptoms were significantly as sociated with female sex, seeing another ill person, knowing that a classma te was ill, and reporting an unusual odor at the school. Conclusions: This illness, attributed to toxic exposure, had features of ma ss psychogenic illness - notably, widespread subjective symptoms thought to be associated with environmental exposure to a toxic substance in the abse nce of objective evidence of an environmental cause. (N Engl J Med 2000;342 :96-100.) (C) 2000, Massachusetts Medical Society.