Environmental influences are very complex, continuously changing, and only partially accessible to scientific investigation. Therefore subjective causal attributions can be difficult to prove and also to disprove. When patients attribute their symptoms to environmental triggers and perceive health threats from commonly used chemical agents or electromagnetic radiation, scientific procedures can frequently not demonstrate any causal relationships. Typical examples are “multiple chemical sensitivity”, MCS (better: “idiopathic environmental intolerances”, IEI), a generalized self-reported hypersensitivity to ubiquitous chemicals, or “amalgam sensitivity”, where symptoms are attributed to amalgam from dental fillings. Environmentally related health disorders which have marked adverse effects on the quality of life, but for which thorough investigation reveals no cause, can best be seen as somatoform disorders and treated on the basis of modern psychosomatic concepts.
