Collective behaviors: mass panic and outbreaks of multiple unexplained symptoms.

The general public, the mass media, and many government officials believe that the use of weapons of mass destruction (WMD) will inevitably lead to mass panic and/or mass hysteria. However, studies of disasters and wars show that disorganized flight in the presence of a real or perceived danger (i.e., mass panic) is rare. On the other hand, in a real or perceived WMD scenario, outbreaks of multiple unexplained symptoms (i.e., mass psychogenic illness, mass sociogenic illness, mass hysteria, or epidemic hysteria) may be prevalent. Many of the symptoms (fatigue, nausea, vomiting, headache, dizziness/lightheadedness, and anorexia) are common in combat and after toxic chemical exposure, chemical weapon exposure, prodromal infectious illness, and acute radiation sickness.