Idiopathic environmental intolerance: Psychiatric perspectives

The expression " Idiopathic Environmental Intolerance" (IEI) is used to describe people with numerous troubling symptoms attributed to environmental factors. The term environmental illness (also known as multiple chemical sensitivity) was used for many years to refer to a subjective illness in certain persons who typically describe multiple symptoms, which they attribute to numerous and varied environmental chemical exposures, in the absence of objective diagnostic physical findings or laboratory test abnormalities that define an illness. Other terms, such as universal allergy, 20th-century disease, chemical hypersensitivity syndrome, total allergy syndrome, and cerebral allergy have also been used to describe the same condition. No consensus has yet been reached for a case definition. All proposed definitions differ by some key criteria. This lack of a clear case definition continues to hamper the epidemiological and clinical research necessary to obtain the data to clarify the prevalence, etiology, diagnosis, and management of Idiopathic Environmental Intolerance. T. Randolph first proposed the existence of environmental sensitivity as a medical illness in the 1950s. Randolph suggested that human failure to adapt to modern-day synthetic chemicals had resulted in a new form of sensitivity to these substances. His concern with foods then expanded to encompass a wide range of environmental chemicals. Most physicians who diagnose and treat IEI identify themselves as "clinical ecologists" or "specialists in environmental medicine". Clinical ecology is not a recognized medical specialty. The central focus of the diagnosis is the fact that the patient describes symptoms in relation to environmental exposures. The list of environmental chemical exposures triggering symptoms is virtually unlimited. The more common ones cited are perfumes and scented products, pesticides, domestic and industrial solvents, new carpets, car exhaust, gasoline and diesel fumes, urban air pollution, cigarette smoke, plastics, and formaldehyde. In many patients symptoms are triggered also by certain foods, food additives, and drugs and in some cases by electromagnetic fields and mercury in dental fillings. Certain environmental irritants, including some of those mentioned above, are recognized as triggers for patients with asthma and rhinitis. However, this phenomenon differs from that of Idiopathic Environmental Intolerance in that objective changes of bronchial or nasal obstruction and hypersecretion occur rather than subjective symptoms only. Symptoms are wide ranging and suggest illness in multiple organ systems, even though objective examinations fail to reveal any structural or functional abnormalities. Theories of the cause and pathogenesis of environmental sensitivity are numerous and frequently change. Many are based on unconventional and controversial concepts and testing methods. Allergic toxemia, Allergic theory, Autoimmune theory, Immunotoxic theory, Neurotoxic theory, Sociogenic theories, Conditioned-response theory, Psychogenic theories are some examples that have been proposed to explain the pathogenesis of IEI. The variety of physical symptoms involving the musculoskeletal system, joints, gastrointestinal tract, and cardiopulmonary system and the host of non-specific complaints in patients who have no physical or laboratory evidence of disease are compatible with conversion reactions, anxiety and depression, or psychosomatic illness. A high prevalence of current and past depression, anxiety, somatization, conversion, obsessive-compulsive, and panic disorders have been found in patients with environmental sensitivity. Patients typically reject any suggestion that they are psychiatrically ill, preferring the explanation that the illness is physical. There is a strong consensus that environmental sensitivity is best explained as a psychosocial condition and that the clinical features are similar to those of other popular, but controversial, syndromes. Also, Clinical ecologists often recognize the presence of psychopathology in their patients, but they view this finding as the result rather than the cause of the illness. There is no consensus about the most effective means of managing patients with environmental sensitivity. Any rational program of treatment is hampered by the continuing controversy about the cause of the condition, lack of a case definition that satisfies most physicians who see these patients, heterogeneity of the clinical manifestations, and subjective nature of the illness. Most patients are resistant to certain therapeutic recommendations because of their own interpretation of the meaning of environmental sensitivity. Reasonable goals are an improvement in the patient's quality of life and improved understanding of factors that contribute to the illness. The phenomenon of environmental sensitivity needs to be evaluated critically using scientifically sound methods.

Key words: Idiopathic Environmental Intolerance, Multiple Chemical Sensitivity, Allergy, Total Allergy Syndrome, Somatization, Depression, Conversion.