What causes an outbreak of mass psychogenic illness?
Many outbreaks of mass psychogenic illness start with an environmental "trigger." The environmental trigger can be a bad smell, a suspicious-looking substance or something else that makes people in a group believe they have been exposed to a germ or a poison.
When an environmental trigger makes a group of people believe they might have been exposed to something dangerous, many of them may begin to experience signs of sickness at the same time. They might experience headache, dizziness, faintness, weakness or a choking feeling. In some cases, one person gets sick and then other people in the group also start feeling sick.
Why do people who are experiencing mass psychogenic illness feel sick?
Think of how "stage fright" can cause nausea, shortness of breath, headache, dizziness, a racing heart, a stomachache or diarrhea. Your body can have a similar strong reaction to other stressful situations. Outbreaks of mass psychogenic illness show us how stress and other people's feelings and behavior can affect the way we feel. People who feel sick in an outbreak of mass psychogenic illness really believe it is possible that they have been exposed to something harmful.
An outbreak of mass psychogenic illness is a time of anxiety and worry. During an outbreak, a lot of media coverage and the presence of ambulances or emergency workers can make you and other people feel more anxious and at risk. At such a time, if you hear about someone getting sick or if you see someone get sick, it can be enough to make you feel sick too.
Does this mean that the sickness is "all in my head"?
No, it doesn't. People who are involved in these outbreaks have real signs of sickness that are not imagined. They really do have headaches, or they really do feel dizzy. But in cases of mass psychogenic illness, these symptoms are not caused by a poison or a germ. The symptoms are caused by stress and anxiety, or by your belief that you have been exposed to something harmful.
Psychogenic illness can affect normal, healthy people. Just because you reacted this way to the threat of something dangerous does not mean there is something wrong with your mind.
Mass Psychogenic Illness: Role of the Individual Physician by TF Jones, MD (American Family Physician December 15, 2000, http://www.aafp.org/afp/20001215/2649.html)
Written by familydoctor.org editorial staff