New Environmental Illnesses: What Are Their Characteristics?
Authors: Peter Henningsen, Stefan Priebe
Journal: Psychotherapy and Psychosomatics (2003)

Recent years have seen the emergence of a number of new illnesses that are attributed to environmental factors and named after their alleged aetiology. A prototypical example is the idiopathic environmental illness, better known by its former name of multiple chemical sensitivity (MCS) [1]. Other illnesses relate to more specific environmental factors. They include Gulf War Syndrome [2], syndromes related to dental amalgam [3]and silicone breast implants [4], electrical hypersensitivity [5], sick building syndrome [6], including toner-related illness, and so-called painter-related encephalopathy [7]. The list seems to get longer by the year. The severity of the illnesses ranges from a slight adversity to fully disabling conditions. In all of them patients strongly believe that their symptoms were caused by exposure to pathogenic environmental factors.Most of these illnesses have been the subject of much public and scientific debate. They have been widely covered in the press and publicised through the internet [8]. Research has mainly focused on investigating each illness separately, trying to establish empirically whether there is a link between the symptoms of the patients and the alleged environmental agent [9].This type of research tends to overlook striking similarities between the new environmental illnesses. The similarities might be more relevant than the differences between the illnesses and may make it useful to study features of a possible general pattern behind them.In addition to the patients attributing their condition to environmental factors, the illnesses all share four important aspects.(1) Patients present with psychological and medically unexplained physical symptoms that are non-specific and overlap significantly. No matter whether they suffer from MCS, electrical hypersensitivity, silicone breast implant-related or any other new environmental illness: all the patients complain of pain in various parts of the body, fatigue and difficulties to concentrate [10, 11]. There are no pathognomonic symptoms or signs in any of these illnesses, although certain types of symptoms are particularly frequent in some. Examples are skin irritation in sick building syndrome and cacosmia in MCS. The symptomatology does not just overlap within the group of environmental illnesses, but also between these illnesses and other functional somatic syndromes. This has been demonstrated for MCS and chronic fatigue syndrome (CFS). No less than 30–40% of patients diagnosed as having MCS were also reported to fulfil criteria for CFS [12]. The symptoms of the new illnesses are not consistently associated with objective physical or laboratory abnormalities.(2) Research has failed to establish an epidemiological or pathophysiological link between the environmental factor alleged to have caused the symptoms and the subsequent illness. The association between cause and effect suggested by the name of the illnesses lacks unequivocal empirical evidence [9, 13], even though relatively much effort and funding have been spent on systematic and methodologically sound studies in the field. Of course, this does not rule out the possibility that such a link may be revealed in the future, in which case the illness in question would no longer qualify as one of the new environmental illnesses we are discussing here.(3) The lack of empirical evidence for a toxicological or other biological cause has little, if any, persuasive effect on the patients concerned and does not make them abandon their environmental explanation. They actively reject the possibility of psychosocial reasons for their illness (indeed they often heavily criticise the researchers who found the negative result) and regard the findings as either useless or inconclusive. They feel misunderstood by their doctors, who fail to confirm their explanation, and may contest their authority as well as that of the medical profession as a whole [14, 15]. There are patient support groups for all of the new illnesses. The groups usually communicate on the internet and some of them are well organised and active.(4) Whilst the causal attributions of the patients first and foremost refer to the environment, there nevertheless is an interpersonal quality to their beliefs. Usually, someone is considered responsible for the pathogenic features of the environment, for the patient's exposure to it or for not preparing the patient appropriately: an employer or landlord who failed to make sure that the patient would not get harmed by the environment they were working or living in; politicians or army generals who did not warn the patient about or protect them from potentially harmful exposure to adverse environmental agents; a company that sold a product without proper warning about a potentially negative impact on the patient's health, thus seeking profit at the expense of the patient's health. Attempts to seek financial compensation are frequent but not inevitable, and they do not seem to be part of the tendency to regard other people as ultimately responsible for the personal misery that is directly attributed to environmental factors. Many patients declare they would be satisfied with an apology of the person or group responsible and an acknowledgement of their responsibility.The central feature of the new environmental illnesses is the firmly held belief that the illness is due to environmental factors, even though this is not consistent with empirical evidence and medical textbooks. This aspect makes the illnesses resemble culture-bound syndromes [16], which also feature medically unexplained and mostly psychological symptoms. In culture-bound syndromes, patients have a causal explanation for their symptoms that is not compatible with models of Western medicine. Unlike the culture-bound syndromes, the new illnesses occur in Western countries. Yet their prevalence varies greatly between countries, suggesting an influence of national cultural factors.Assumptions that environmental agents cause certain illnesses might reflect increasing environmental health concerns in general. The assumptions have to be tested in research [17]. For example, the potential health hazards of electromagnetic fields emitted by mobile phones and transmitter stations have to be investigated with rigorous methods before a causal relationship between the environmental agent and the given syndrome can be either confirmed or dismissed. Such research takes time and its results are regularly challenged by various interest groups, no matter how conclusive they actually are. The influence of special interest groups on regulatory bodies is well documented not only for the pharmaceutical industry, but also in the field of environmental health concerns, where even undisputable evidence of cancer risks, as in the case of asbestos, has been questioned or even denied by such groups and the regulatory bodies infiltrated by them [18, 19]. Thus, even in cases of 'true' environmental illnesses, the scientific community has – at least initially – often failed to provide a clear and consistent message. This might have further encouraged the scepticism about the negative results on new environmental illnesses we are witnessing now.However, there are important limitations not just to the message but also to the research itself. Even in methodologically sound epidemiological studies, it can obviously be very difficult to establish or exclude causal links (rather than chance associations) between widespread low-dose expositions and unspecific complaints and symptoms. Frequent methodological problems include insufficient baseline information, high variability of individual vulnerability, 'soft' rather than 'hard' health-related end points and ill-defined boundaries of symptom clusters [20, 21]. Also, failure of epidemiological research to demonstrate an association between exposure to a certain environmental agent and the subsequent symptoms does not exclude the possibility that a causal relationship might exist in individual cases. Additionally, all such results are limited by the sensitivity of the assessment tools applied, and it can often be argued that more sensitive methods would have revealed more symptoms in the people exposed to an environmental agent than in a control group. Whilst negative results are not consistent with the assumption of an alleged environmental cause, they naturally do not address the nature of a possible aetiological process. They cannot provide an alternative positive explanation for the symptoms that patients could accept instead of their existing beliefs. For all these reasons, it may at least be understandable why negative research results often have no overwhelming persuasive effect.We argue that the causal attributions made by the patients are better suited to characterise the new illnesses than theories about specific aetiologies. These attributions have a similar structure in all of the new illnesses, no matter how different they might be in other respects. The content may be syndrome specific, i.e. the attribution of a certain symptom to specific environmental factors and blaming a certain person, but the new illnesses share formal features. The formal features include a strong and fixed belief that is difficult or even impossible to change through reasoning (on the basis of rational argument) and the evidence provided by medical research [22]. In psychopathological terms, this would qualify as an overvalued idea or, depending on how rigid and clearly inconsistent with obvious evidence the belief is, even a delusion. However, such psychopathological classification alone helps, at best, to label the phenomenon. Beyond that, it has little heuristic value and hardly opens up new options for diagnosis and care.How can this hypothesis be tested and what are the implications? Research on explanatory models has so far mainly dealt with transcultural issues [23], and specific validated methods to assess explanatory models, including the above-mentioned formal features in the populations concerned, have not been established yet. The challenge is first to describe the models in more detail and confirm the consistency across the new illnesses, and second to understand why patients hold on to or give them up and in what way the interpersonal aspect of holding other people responsible is an essential feature – beyond obvious material gains of litigation. Such research requires the development and validation of specific assessment methods. Existing instruments to measure cognition and attitudes of patients and health professionals such as the 'Modern Health Worry Scale' [24]may be taken as a starting point. Also, the Diagnostic Criteria for Psychosomatic Research (DCPR) [25], which go beyond ICD-10 or DSM-IV in that they provide operationalisations for symptom-based conditions (e.g. persistent somatisation) and relevant cognitions (e.g. health anxiety or disease phobia), are likely to be helpful.Large-scale outbreaks of environmentally related syndromes in a population that has been screened for baseline symptoms and for modern health worries [26]can be an ideal opportunity to study specific environmental illnesses in more detail. We suggest, however, that the application of consistent methods across different new environmental illnesses might be particularly useful to demonstrate common and distinct features of new environmental illnesses. Longitudinal studies should preferably combine quantitative and qualitative methods. A quantitative approach may analyse different patterns and courses of new environmental illnesses as well as predictors of more or less favourable outcome, and might identify the mediating influence of biological, psychological and social factors, including the effect of risk communication [27], health care interventions and social support. The results can be used to sample smaller groups purposively for in-depth qualitative research into the processes that determine outcome. The findings of qualitative investigations might be used to inform the concepts and methodology of further large-scale studies and design specific interventions that can be tested in experimental research.The relationship between the patient's and the health professional's explanatory model and its impact on outcome may warrant special research attention. Modern health worries have been shown to be associated with increased consultations of 'alternative' health professionals, but not with increased consultations of conventional medical professionals. One can assume that 'alternative' health professionals are more likely to share the environment-focused explanations for the symptoms, thereby avoiding the conflicts mentioned above [24].Another implication of our hypothesis is the call for interdisciplinary research into the reasons for the popularity of new environmental illnesses. Comparative studies should analyse why certain environmental illnesses are more popular in some Western countries than in others, not just among patients but also among some doctors and other health professionals.If the hypothesis and our suggestions are correct, less effort and money might be spent on fruitless debates on the 'true cause' of the patients' syndrome and directed towards targeting an equally psychological, social and biological phenomenon that has become a major challenge to health care in many Western countries – illness rather than organic disease should be the focus of research [28]. Simply considering the explanatory models of the patients as irrational and unreasonable will not help to improve care for the patients who are distressed by their symptoms and feel let down by the medical profession. At present, doctors tend to reject the causal explanations of the patients, yet they are not in a position to offer alternative models other than – possibly – vague and non-specific psychosocial ones. Specific research should address the explanatory models of the patients in the context of their experiences with health professionals, scientists, and media, and initiate ways to deal with them on a societal and individual level.We declare that no conflict of interest was involved in writing this paper.