Is the Diagnosis of "Mass Hysteria" an Excuse for Incomplete Investigation of Low-Level Environmental Contamination?

"Mass hysteria" is an epidemic diagnostic term used to characterize unexplained outbreaks of syncope among women. A syncope outbreak among women in a meeting in a rural area of Michigan prompted an intense investigation for etiology. Low levels of ozone; carbon monoxide, and pentane were found associated with the outbreak. These levels were too low by themselves to explain the symptoms. A sociometric scale of intensity of illness was devised and found to be highly correlated (r = -0.94) with the weight of those who fainted. It is argued that mass hysteria may be the result of interactions of low levels of toxicants and may not be a result of the "hysterical" behavior in women at all.