Environmental illness is all in the head and in a very disturbed head, at that.
At least that's the conclusion of a study of people suffering from "20th century disease" multiple allergies and intolerances to food and chemicals published in the Journal of the American Medical Association.
Using a questionnaire entitled the "Diagnostic Interview Schedule," the researchers from the Department of Psychiatry at the University of Iowa College of Medicine found that l5 of their 23 subjects met the criteria for a "current or past mood, anxiety or somatoform disorder.
"We conclude that patients receiving this diagnosis may have one or more commonly recognized psychiatric disorders that could explain some or all of their symptoms," wrote the researchers.
A similar conclusion was reached by a study of 37 plastics workers published in the American Journal of Psychiatry that environmental illness has its roots in the psyche, and not in the immune system.
In a column in the January Townsend Letter for Doctors, Dr Alan Gaby, commenting on the plastics workers study, said that although "psychological vulnerability" can affect the immune system, the authors don't consider that environmental allergies can cause mental problems, too.
"Chemically sensitive individuals may have a prior history of psychological disturbances because of chronic cerebral allergic reactions," wrote Gaby. "An effective treatment approach to environmental illness requires attention both to the physical and psychological aspects of this complex condition."