Evidence for overlap between idiopathic environmental intolerance and somatoform disorders

Multiple Chemical Sensitivity/Idiopathic Environmental Intolerance: A Practical Approach to Diagnosis and Management

Patients with multiple chemical sensitivity, now called idiopathic environmental intolerance, frequently present to clinical immunologists and allergists for diagnosis and treatment. Patients report a plethora of respiratory and multisystem problems attributed to a wide variety of unrelated, otherwise non-noxious, triggers. They may go to extreme, often seemingly bizarre lengths to avoid contact with everyday exposures and may become housebound, unable to work or function socially. Often beginning with exposure to odors, triggers can multiply to involve foods, clothing, medications, and even electromagnetic radiation. The condition cannot be explained by IgE-mediated or other immune processes, and clinical immunologists and allergists may feel unprepared to care for such patients. In this article, a paradigm to understand the probable mechanisms underlying this condition and a practical approach to diagnosis and management will be presented.

Road traffic noise, noise sensitivity, noise annoyance, psychological and physical health and mortality

BACKGROUND

Both physical and psychological health outcomes have been associated with exposure to environmental noise. Noise sensitivity could have the same moderating effect on physical and psychological health outcomes related to environmental noise exposure as on annoyance but this has been little tested.

METHODS

A cohort of 2398 men between 45 and 59 years, the longitudinal Caerphilly Collaborative Heart Disease study, was established in 1984/88 and followed into the mid-1990s. Road traffic noise maps were assessed at baseline. Psychological ill-health was measured in phase 2 in 1984/88, phase 3 (1989/93) and phase 4 (1993/7). Ischaemic heart disease was measured in clinic at baseline and through hospital records and records of deaths during follow up. We examined the longitudinal associations between road traffic noise and ischaemic heart disease morbidity and mortality using Cox Proportional Hazard Models and psychological ill-health using Logistic Regression; we also examined whether noise sensitivity and noise annoyance might moderate these associations. We also tested if noise sensitivity and noise annoyance were longitudinal predictors of ischaemic heart disease morbidity and mortality and psychological ill-health.

RESULTS

Road traffic noise was not associated with ischaemic heart disease morbidity or mortality. Neither noise sensitivity nor noise annoyance moderated the effects of road traffic noise on ischaemic heart disease morbidity or mortality. High noise sensitivity was associated with lower ischaemic heart disease mortality risk (HR = 0.74, 95%CI 0.57, 0.97). Road traffic noise was associated with Phase 4 psychological ill-health but only among those exposed to 56-60dBA (fully adjusted OR = 1.82 95%CI 1.07, 3.07). Noise sensitivity moderated the association of road traffic noise exposure with psychological ill-health. High noise sensitivity was associated longitudinally with psychological ill-health at phase 3 (OR = 1.85 95%CI 1.23, 2.78) and phase 4 (OR = 1.65 95%CI 1.09, 2.50). Noise annoyance predicted psychological ill-health at phase 4 (OR = 2.47 95%CI 1.00, 6.13).

CONCLUSIONS

Noise sensitivity is a specific predictor of psychological ill-health and may be part of a wider construct of environmental susceptibility. Noise sensitivity may increase the risk of psychological ill-health when exposed to road traffic noise. Noise annoyance may be a mediator of the effects of road traffic noise on psychological ill-health.

Letter to the Study by Hyvönen et al. on Moisture Damage and MCS

Due to the significant methodological problems in the empirical part of the paper and the very selective literature review, the conclusions of the paper are mostly unsupported.

"Symptoms associated with environmental factors" (SAEF) - Towards a paradigm shift regarding "idiopathic environmental intolerance" and related phenomena

Health conditions characterized by symptoms associated with chemical, physical and biological environmental factors unrelated to objectifiable pathophysiological mechanisms are often labelled by the general term "idiopathic environmental intolerances". More specific, exposure-related terms are also used, e.g. "multiple chemical sensitivities", "electromagnetic hypersensitivity" and "candidiasis hypersensitivity". The prevalence of the conditions varies from a few up to more than 50%, depending on definitions and populations. Based on evolving knowledge within this field, we provide arguments for a paradigm shift from terms focusing on exposure and intolerance/(hyper-)sensitivity towards a term more in line with the perceptual elements that seem to underlie these phenomena. Symptoms caused by established pathophysiologic mechanisms should not be included, e.g. allergic or toxicological conditions, lactose intolerance or infections. We discuss different alternatives for a new term/concept and end up proposing an open and descriptive term, "symptoms associated with environmental factors" (SAEF), including a definition. "Symptoms associated with environmental factors" both is in line with the current knowledge and acknowledge the experiences of the afflicted persons. Thus, the proposed concept is likely to facilitate therapy and communication between health professionals and afflicted persons, and to provide a base for better understanding of such phenomena in healthcare, society and science.

One Single Question Is not Sufficient to Identify Individuals With Electromagnetic Hypersensitivity

Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF) is a self-reported condition where non-specific symptoms are attributed to weak non-ionizing electromagnetic fields. Despite its expanding prevalence, there is no generally accepted diagnostic procedure or definition to identify patients with this condition, thus studies usually apply only one question as inclusion criterion. The aim of our study was to demonstrate the heterogeneity of a self-reported IEI-EMF group and to identify further self-report questions that could be applied as inclusion criteria.

Cross-sectional on-line survey study was carried out with 473 participants (76.3% women; age: 35.03 ± 13.24 yrs). Self-diagnosed IEI-EMF (as assessed with a yes-or-no question), frequency of EMF-related symptom and severity of the condition were assessed, as well as somatic symptom distress (Patient Health Questionnaire Somatic Symptom Severity Scale, PHQ-15).

72 (15.2%) individuals labelled themselves as IEI-EMF, however only 61% of them remained in the IEI-EMF group after the use of three inclusion criteria instead of one. 21% of the individuals labelling themselves as IEI-EMF reported neither symptoms nor any negative impact on their daily life.

A minimum of two questions appear to be necessary as inclusion criteria for IEI-EMF in empirical research. Instead of the widely used yes-or-no question on accepting the IEI-EMF label, occurrence of symptoms attributed to EMF on a regular basis and at least a slight negative impact on daily life are required.

Electromagnetic hypersensitivity (IEI-EMF) is often assessed by one yes-or-no self-report question.

This practice is inappropriate from a conceptual and methodological point of view.

At least two questions, assessing frequency of symptoms and their impact, are needed.

Health-related quality among life of employees with persistent nonspecific indoor-air-associated health complaints

OBJECTIVE

Nonspecific health complaints associated with indoor air are common in work environments. In some individuals, symptoms become persistent without an adequate explanation. The aim was to study factors that associate with the health-related quality of life (HRQoL) of employees with persistent, nonspecific indoor-air-related symptomatology.

METHODS

We present baseline results of a randomized controlled trial of interventions targeted on the HRQoL of the employees with indoor-air-associated nonspecific symptoms. The main participant-inclusion criterion was the presence of persistent indoor-air-related multiorgan symptoms with no known pathophysiological or environment-related explanation. As a comparison for participants´ HRQoL (n = 52) we used data from the general-population Health 2011 study (BRIF8901) including information on subjects matched to the participants´ working status and age and subjects with asthma, anxiety or depressive disorder, or other chronic conditions with work disability.

RESULTS

The participants showed greater and a clinically significant impairment of HRQoL [M = 0.83, SE = 0.013] than individuals from the general population [M = 0.95, SE = 0.001, p < .001, Hedges´ g = 2.33] and those with asthma [M = 0.93, SE = 0.005, p < .001, Hedges´ g = 1.46], anxiety and depressive disorder [M = 0.89, SE = 0.006, p < .001, Hedges´ g = 0.73], or a chronic condition with work disability [M = 0.91, SE = 0.003, p < .001, Hedges´ g = 1.11]. Prevalent symptoms of depression, anxiety, and insomnia and poor recovery from work were associated with a poor HRQoL.

CONCLUSIONS

Individuals with nonspecific indoor-air-associated symptoms have a poorer HRQoL than individuals in the general population with a globally burdensome disease. Psychological distress associated with a poor HRQoL should be considered in the making of decisions about the treatment of these patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02069002.

Longitudinal associations between risk appraisal of base stations for mobile phones, radio or television and non-specific symptoms

INTRODUCTION

Studies found that higher risk appraisal of radiofrequency electromagnetic fields is associated with reporting more non-specific symptoms such as headache and back pain. There is limited data available on the longitudinal nature of such associations and what aspects of risk appraisal and characteristics of subjects are relevant.

OBJECTIVE

To examine cross-sectional and longitudinal associations between risk appraisal measures and non-specific symptoms, and assess the role of subject characteristics (sex, age, education, trait negative affect) in a general population cohort.

METHODS

This study was nested in the Dutch general population AMIGO cohort that was established in 2011/2012, when participants were 31-65 years old. We studied a sample of participants (n = 1720) who filled in two follow-up questionnaires in 2013 and 2014, including questions about perceived exposure, perceived risk, and health concerns as indicators of risk appraisal of base stations, and non-specific symptoms.

RESULTS

Perceived exposure, perceived risk, and health concerns, respectively, were associated with higher symptom scores in cross-sectional and longitudinal analyses. Only health concerns (not perceived exposure and perceived risk) temporally preceded high symptom scores and vice versa. Female sex, younger age, higher education, and higher trait negative affect were associated with higher risk appraisal of mobile phone base stations.

DISCUSSION

The findings in this study strengthen the evidence base for cross-sectional and longitudinal associations between higher risk appraisal and non-specific symptoms in the general population. However, the directionality of potential causal relations in non-sensitive general population samples should be examined further in future studies, providing information to the benefit of risk communication strategies.

Prevalence of various environmental intolerances in a Swedish and Finnish general population

OBJECTIVE

To determine the prevalence of various environmental intolerances (EIs), using several criteria in a Swedish and a Finnish general population. Ill-health attributed to low-level environmental exposures is a commonly encountered challenge in occupational and environmental medicine.

METHODS

In population-based questionnaire surveys, the Västerbotten Environmental Health Study (Sweden) and the Österbotten Environmental Health Study (Finland), EI was inquired by one-item questions on symptom attribution to chemicals, certain buildings, or electromagnetic fields (EMFs), and difficulties tolerating sounds. The respondents were asked whether they react with central nervous system (CNS) symptoms or have a physician-diagnosed EI attributed to the corresponding exposures. Prevalence rates were determined for different age and sex groups and the Swedish and Finnish samples in general.

RESULTS

In the Swedish sample (n = 3406), 12.2% had self-reported intolerance to chemicals, 4.8% to certain buildings, 2.7% to EMFs, and 9.2% to sounds. The prevalence rates for the Finnish sample (n = 1535) were 15.2%, 7.2%, 1.6%, and 5.4%, respectively, differing statistically significantly from the Swedish. EI to chemicals and certain buildings was more prevalent in Finland, while EI to EMFs and sounds more prevalent in Sweden. The prevalence rates for EI with CNS-symptoms were lower and physician-diagnosed EIs considerably lower than self-reported EIs. Women reported EI more often than men and the young (18-39 years) to a lesser degree than middle-aged and elderly.

CONCLUSIONS

The findings reflect the heterogeneous nature of EI. The differences in EI prevalence between the countries might reflect disparities concerning which exposures people perceive harmful and focus their attention to.

Differences in psychological and somatic symptom cluster score profiles between subjects with Idiopathic environmental intolerance, major depression and schizophrenia

Idiopathic Environmental Intolerance (IEI) has been associated with psychogenic factors and an increased number of comorbid psychiatric disorders such as depression and anxiety disorder. The purpose of the current study was to examine a possible overlap of psychological and somatic symptoms between subjects with IEI and patients with major depression and schizophrenia as well as to specify characteristic differences. The different symptom clusters included symptoms of chemical intolerance, neurotoxicity and psychological distress as well as measurements of mental health such as anxiety, depression, somatoform symptoms, and schizophrenia-specific disturbances in cognitive domains. IEI patients reported higher overall levels in physical symptoms such as chemical intolerance, neurotoxicity and somatic symptoms not attributable to an organic cause. Schizophrenia patients showed higher overall levels in self-experienced disturbances in several schizophrenia-specific cognitive domains, whereas general psychological distress, anxiety and depression were rated highest by patients with major depression. Importantly, the groups markedly differed in the shapes of profiles of various symptom clusters. Our results provide evidence that IEI patients can be distinguished on the phenomenological level from patients with major depression or schizophrenia, and that distinct domains of psychological and somatic symptoms are particularly problematic in specific diagnostic groups.

Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session

OBJECTIVES

To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure.

DESIGN

Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure.

SETTINGS

Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper.

PARTICIPANTS

36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls.

OUTCOME MEASURES

17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels.

RESULTS

MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls.

CONCLUSIONS

MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure.

Attribution-Based Nocebo Effects. Perceived Effects of a Placebo Pill and a Sham Magnetic Field on Cognitive Performance and Somatic Symptoms

BACKGROUND

Negative non-specific (nocebo-like) effects of medications and electromagnetic fields are often described as results of mistaken attribution.

PURPOSE

The current study aimed to find empirical evidence supporting this theory.

METHOD

Participants completed questionnaires assessing modern health worries, health anxiety, and somatosensory amplification, were assigned to one of three conditions (placebo pill with sedative information, sham magnetic field, or control), and completed a 14-min vigilance task. Changes in physiological arousal (heart rate, heart rate variability, and skin conductance) and reported symptoms were also measured. Finally, causal attributions concerning cognitive performance and reported symptoms were assessed.

RESULTS

No increase in symptom reports and physiological arousal was measured in the two intervention groups. A perceived negative effect on cognitive performance was attributed to both sham conditions, and attributions were connected to modern health worries. A proportion of reported symptoms was ascribed to the placebo pill but not to the sham magnetic field. Symptom attributions were not related to any assessed psychological variables.

CONCLUSIONS

An aroused physiological state is not necessary for the automatic causal attribution process. Negative effects attributed to medication and environmental factors can be regarded as unavoidable side effects of human cognitive-emotional functioning; they might be alleviated, but cannot be completely eradicated.

Health effects from low-frequency noise and infrasound in the general population: Is it time to listen? A systematic review of observational studies

A systematic review of observational studies was conducted to assess the association between everyday life low-frequency noise (LFN) components, including infrasound and health effects in the general population. Literature databases Pubmed, Embase and PsycInfo and additional bibliographic sources such as reference sections of key publications and journal databases were searched for peer-reviewed studies published from 2000 to 2015. Seven studies met the inclusion criteria. Most of them examined subjective annoyance as primary outcome. The adequacy of provided information in the included papers and methodological quality of studies was also addressed. Moreover, studies were screened for meta-analysis eligibility. Some associations were observed between exposure to LFN and annoyance, sleep-related problems, concentration difficulties and headache in the adult population living in the vicinity of a range of LFN sources. However, evidence, especially in relation to chronic medical conditions, was very limited. The estimated pooled prevalence of high subjective annoyance attributed to LFN was about 10%. Epidemiological research on LFN and health effects is scarce and suffers from methodological shortcomings. Low frequency noise in the everyday environment constitutes an issue that requires more research attention, particularly for people living in the vicinity of relevant sources.

Psychological symptoms and health-related quality of life in idiopathic environmental intolerance attributed to electromagnetic fields

OBJECTIVE

Need for better understanding of the etiology of idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) motivated the present study of psychological symptoms and health-related quality of life (HRQoL) in person who attribute health problems to electromagnetic fields.

METHODS

Participants with IEI-EMF (n=114) and a population-based sample of referents (n=104) were investigated with six subscales of the Symptom Checklist 90 (SCL-90) to assess psychological symptoms, and with eight subscales of the Short Form (36) Health Survey (SF-36) to assess HRQoL.

RESULTS

Significantly higher scores were found on obsessive/compulsive behavior, interpersonal hypersensitivity, hostility, phobic anxiety, paranoid thoughts in the IEI-EMF group compared to referents, whereas only a tendency of such a difference was found for psychotism. Furthermore, poorer HRQoL in the IEI-EMF group, compared to referents, were found regarding physical and social functioning, physical and emotional role limitations, general health, vitality, bodily pain, and mental health. Significant correlation with moderate to strong effect sizes were found between several of the SCL-90 and SF-36 subscales.

CONCLUSION

The results suggest that IEI-EMF is associated with various types of psychological symptoms and with poor HRQoL. Clinical implications include theoretical support for cognitive behavioral therapy, and, although further research is needed, that attention should be directed towards feelings of inferiority and uneasiness in relationships as well as anger, hostility and resentment towards other people.

Interindividual differences in chemosensory perception: Toward a better understanding of perceptual ratings during chemical exposures

Perceptions that arise from stimulation of olfactory and trigeminal receptors in the nasal cavity guide the evaluation of chemical environment in humans. Strong interindividual differences in these assessments may be attributed to nonsensory factors such as gender, anxiety, and chemical sensitivity. Knowledge regarding the influence of these factors originates mainly from basic odor research using short-term exposure scenarios. In situations with continuous chemical exposures-common in the working environment-their impact is less clear. To investigate their role during the exposure to workplace chemicals, 4-hour experimental exposure studies (total N = 105) using nine different airborne chemicals were summarized. In each study, subjects evaluated a single chemical in a controlled environment by rating five chemosensory perceptions, including odor intensity, disgust, annoyance, pungency, and burning, several times during occupational limit and low exposures. It was investigated whether the effects of trait-like modulators, such as anxiety and self-reported chemical sensitivity, depend on exposure-related factors and gender. Trait-like modulators markedly affected ratings by women, but not men. Highly anxious women reported more intense annoyance and disgust than less anxious women. Stronger self-reported chemical sensitivity was associated with increased ratings of pungency and burning in women exposed to occupational limit concentrations. This study demonstrates that a complex interplay of exposure-related factors, gender, and trait-like individual differences affects perceptual ratings during continuous chemical exposure. It seems necessary to incorporate the assessment of specific as well as general trait-like modulators into future experimental exposure studies.

Health anxiety and hypochondriasis in the light of DSM-5

BACKGROUND

In the DSM-5, the diagnosis of hypochondriasis was replaced by two new diagnositic entities: somatic symptom disorder (SSD) and illness anxiety disorder (IAD). Both diagnoses share high health anxiety as a common criterion, but additonal somatic symptoms are only required for SSD but not IAD.

DESIGN

Our aim was to provide empirical evidence for the validity of these new diagnoses using data from a case-control study of highly health-anxious (n = 96), depressed (n = 52), and healthy (n = 52) individuals.

RESULTS

The individuals originally diagnosed as DSM-IV hypochondriasis predominantly met criteria for SSD (74%) and rarely for IAD (26%). Individuals with SSD were more impaired, had more often comorbid panic and generalized anxiety disorders, and had more medical consultations as those with IAD. Yet, no significant differences were found between SSD and IAD with regard to levels of health anxiety, other hypochondriacial characteristics, illness behavior, somatic symptom attributions, and physical concerns, whereas both groups differed significantly from clinical and healthy controls in all of these variables.

CONCLUSION

These results do not support the proposed splitting of health anxiety/hypochondriasis into two diagnoses. Further validation studies with larger samples and additional control groups are warranted to prove the validity of the new diagnoses.

Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study

Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment.

Medically unexplained symptoms

In summary, caring for patients with MUS is challenging for health care providers. Even defining somatization syndromes is complex and controversial, reflecting the medical community’s limited understanding of the pathophysiology for this group of disorders. Although risk factors for MUS have been described and are well understood, little is known about how MUS can be prevented. Uncertainty in medicine, as in any human enterprise, is a given, but the difficulties in identification and treatment of patients with MUS highlight the limitations in understanding the intersection between physical and mental health. Patients come to their physician looking for clarity, understanding, and relief of debilitating symptoms. The understanding of MUS will evolve, and perhaps an organic cause not yet understood or described may emerge to lend clarity and therapeutic opportunities to some patients with somatic disorders. In the meantime, the most powerful tools available are the ability to communicate the limits of current understanding, acknowledge the difficulties faced by patients with this disorder, and reinforce the willingness and desire of clinicians to partner with patients as the focus shifts from diagnosis to symptom management. Thus, the physician-patient relationship, still in its rightful place at the heart of the practice of medicine, lies at the center of effective treatment of patients with MUS.

Comparing non-specific physical symptoms in environmentally sensitive patients: prevalence, duration, functional status and illness behavior

OBJECTIVE

Little is known about the potential clinical relevance of non-specific physical symptoms (NSPS) reported by patients with self-reported environmental sensitivities. This study aimed to assess NSPS in people with general environmental sensitivity (GES) and idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) and to determine differences in functional status and illness behavior.

METHODS

An epidemiological study was conducted in the Netherlands, combining self-administered questionnaires with the electronic medical records of the respondents as registered by general practitioners. Analyses included n=5789 registered adult (≥18 years) patients, comprising 5073 non-sensitive (NS) individuals, 514 in the GES group and 202 in the IEI-EMF group.

RESULTS

Participants with GES were about twice as likely to consult alternative therapy compared to non-sensitive individuals; those with IEI-EMF were more than three times as likely. Moreover, there was a higher prevalence of symptoms and medication prescriptions and longer symptom duration among people with sensitivities. Increasing number and duration of self-reported NSPS were associated with functional impairment, illness behavior, negative symptom perceptions and prevalence of GP-registered NSPS in the examined groups.

CONCLUSION

Even after adjustment for medical and psychiatric morbidity, environmentally sensitive individuals experience poorer health, increased illness behavior and more severe NSPS. The number and duration of self-reported NSPS are important components of symptom severity and are associated with characteristics similar to those of NSPS in primary care. The substantial overlap between the sensitive groups strengthens the notion that different types of sensitivities might be part of one, broader environmental illness.

Risks perception of electromagnetic fields in Taiwan: the influence of psychopathology and the degree of sensitivity to electromagnetic fields

Little is known about the perceived health risks of electromagnetic fields (EMFs) and factors associated with risk perception in non-Western countries. Psychological conditions and risk perception have been postulated as factors that facilitate the attribution of health complaints to environmental factors. This study investigated people's perceived risks of EMFs and other environmental sources, as well as the relationships between risk perception, psychopathology, and the degree of self-reported sensitivity to EMFs. A total of 1,251 adults selected from a nationwide telephone interviewing system database responded to a telephone survey about the relationships between environmental sources and human health. The interview included questions assessing participants' psychiatric conditions and the presence and degree of sensitivity to EMFs. One hundred and seventy participants were self-identified as having sensitivity to EMFs, and 141 met the criteria for psychiatric conditions without EMF sensitivity. More than half of the survey respondents considered power lines and mobile phone base stations to affect people's health to a big extent. Higher sensitivity to EMFs, psychopathology, being female, being married, more years of education, and having a catastrophic illness had positive associations with perceived risks of EMF-related environmental sources as well as for all environmental sources combined. We observed no moderating effect of psychopathology on the association between degree of sensitivity to EMF and risk perception. Thus, psychopathology had influence on general people's risk perception without having influence on the relationship between people's degree of sensitivity to EMF and risk perception. The plausible explanations are discussed in the text.

Anaesthesia Management in Patients with Multiple Chemical Sensitivity Syndrome

Multiple Chemical Sensitivity (MCS) is characterised by the appearance of numerous and sometimes severe symptoms, when subjects are in contact with various chemicals and medicinal substances. Currently there are no useful guidelines for managing clinical issues and, specifically, anaesthesia for patients with MCS. This case report describes anaesthesia management in a patient affected by clinically documented MCS and a latex allergy, a candidate for a laparoscopic cholecystectomy operation.

Xenobiotic sensor- and metabolism-related gene variants in environmental sensitivity-related illnesses: a survey on the Italian population

In the environmental sensitivity-related illnesses (SRIs), multiple chemical sensitivity (MCS), chronic fatigue syndrome (FCS), and fibromyalgia (FM), the search for genetic polymorphisms of phase I/II xenobiotic-metabolizing enzymes as suitable diagnostic biomarkers produced so far inconclusive results, due to patient heterogeneity, geographic/ethnic differences in genetic backgrounds, and different methodological approaches. Here, we compared the frequency of gene polymorphisms of selected cytochrome P450 (CYP) metabolizing enzymes and, for the first time, the frequency of the xenobiotic sensor Aryl hydrocarbon receptor (AHR) in the three cohorts of 156 diagnosed MCS, 94 suspected MCS, and 80 FM/FCS patients versus 113 healthy controls. We found significantly higher frequency of polymorphisms CYP2C9∗2, CYP2C9∗3, CYP2C19∗2, CYP2D6∗4 and CYP2D6∗41 in patients compared with controls. This confirms that these genetic variants represent a genetic risk factor for SRI. Moreover, the compound heterozygosity for CYP2C9∗2 and ∗3 variants was useful to discriminate between either MCS or FM/CFS versus SMCS, while the PM ∗41/∗41 genotype discriminated between MCS and either SMCS or FM/CFS. The compound heterozygosity for CYP2C9 ∗1/∗3 and CYP2D6 ∗1/∗4 differentiated MCS and SMCS cases from FM/CFS ones. Interestingly, despite the distribution of the AHR Arg554Lys variant did not result significantly different between SRI cases and controls, it resulted useful for the discrimination between MCS and SMCS cases when considered within haplotypes in combination with CYP2C19 ∗1/∗2 and CYP2D6 ∗1/∗4. Results allowed us to propose the genotyping for these specific CYP variants, together with the AHR Arg554Lys variant, as reliable, cost-effective genetic parameters to be included in the still undefined biomarkers' panel for laboratory diagnosis of the main types of environmental-borne SRI.

The perception of odor is not a surrogate marker for chemical exposure: a review of factors influencing human odor perception

CONTEXT

Clinical toxicologists perform risk assessments and clinical evaluations for patients with potential exposure to airborne toxicants in which the patient's self-reported perception of odor may be the only indicator that an exposure may have taken place.

OBJECTIVE

To review the factors that may affect the human ability to perceive chemical odors and relate those odors to specific chemical exposures.

METHODS

The medical literature, from 1950 through 2012, was searched using the OVID database and the PUBMED database. The searches returned 238 articles, of which 113 involved human studies and were published in the English language. Of these 113 articles, 40 articles discussed odor issues and thus were chosen as specifically relevant to the topic. Bibliographies of all articles were also searched for other relevant references and this found six additional articles, making a total of 46. FACTORS THAT MAY AFFECT OLFACTION AND THE ABILITY TO PERCEIVE ODOR: Genetic/population: Ethnic background is associated with widely differing odor detection abilities and thresholds. A significant genetic influence for the ability to smell and perceive odor has been reported. Gender: Women are superior to men in their ability to identify odors. Age. Increasing age is correlated with higher odor detection thresholds. Medical conditions: A variety of medical conditions have been associated with deficits in olfaction, including diseases of the nose and sinuses, multiple sclerosis, and schizophrenia. Alcoholism and smoking: Abuse of alcohol results in impaired olfactory sense, and smoking tobacco products alters odor detection threshold in a dose-related manner. Occupational and environmental factors: Repeated inhalation of any chemical results in olfactory fatigue over relatively short time frames that leads to a decreased ability to accurately detect and identify an odor. Recent exposure to relatively high concentrations of a chemical has been shown to affect sensitivity to that particular odorant, altering subsequent detection thresholds by up to three orders of magnitude. Applicability of proposed odor thresholds: Humans are only able to identify three to four components of complex olfactory mixtures and the odorants present in the mixture affect which individual components are detected. Odorants present in suprathreshold concentrations in a mixture may effectively mask the presence of odorants present in perithreshold concentrations. Self-rating of olfactory function may not correlate with actual olfactory ability. It is even more difficult to accurately determine intensity of an odor in a quantifiable way. For example, under conditions of constant stimulation with hydrogen sulfide, perceptual intensity was reported to decrease exponentially with time of stimulation. Concomitant visual stimulation also affects odor intensity. Some chemicals, such as hydrogen sulfide, may induce reactions in humans related solely to their odor, even when they are present in concentrations substantially lower than those levels usually associated with the development of adverse clinical effects. There is a wealth of literature suggesting that the intensity of perceived odor, the degree of irritation, and the reported health effects of exposure to an odorant chemical are affected by psychological state and bias. Multiple theories have been proposed to explain the cognitive basis for perceived illness in association with the perception of odor. The concept of odor has been reported to be intrinsically and cognitively associated with illness rather than with health. Assigning negative bias to an odor prior to an exposure results in the reporting of significantly more health-related symptoms following exposure. This suggests that those symptoms are not mediated by the odor directly, but rather by an individual's cognitive associations between odor and health.

CONCLUSIONS

Attempts to verify exposure intensity based on the report of a perceived odor is unreliable and has no useful application in legitimate exposure assessment paradigms. Detection of an odor does not imply a medically significant exposure to a toxicant and, due to subject bias and the difficulty of detecting individual odorants in mixtures, may not constitute an exposure to the purported substance.

Is the subjective perception of lactose intolerance influenced by the psychological profile?

BACKGROUND

Symptoms of lactose intolerance are often attributed to lactose malabsorption but, as this relationship has not been demonstrated when a small dose of lactose similar to that contained in one cup of milk is ingested by intolerant patients, psychological factors may play a role in altered symptom perception.

AIM

To assess the hypothesis that the psychological profile influences the symptoms of lactose intolerance.

METHODS

One hundred and two consecutive patients underwent a 15 g lactose hydrogen breath test to assess lactose malabsorption. The patients recorded the presence and severity of symptoms of lactose intolerance during the breath test using visual analogue scales. The psychological profile was assessed using a psychological symptom checklist, and health-related quality of life by means of the short-form health survey.

RESULTS

Lactose malabsorption and intolerance were diagnosed in, respectively, 18% and 29% of the patients. The two conditions were not associated, and the severity of intolerance was even less in the patients with malabsorption. Multivariate logistic analysis showed that a high somatisation t-score was significantly associated with lactose intolerance (odds ratio 4.184; 1.704-10.309); the effects of the other psychological variables and of lactose malabsorption were not statistically significant. Health-related quality of life was significantly reduced in the patients with somatisation, but not in those with lactose malabsorption.

CONCLUSIONS

The symptoms of lactose intolerance during hydrogen breath testing at a low physiological lactose load, are unrelated to lactose malabsorption, but may reveal a tendency towards somatisation that could impair the quality of life.

Mindfulness-based cognitive therapy for multiple chemical sensitivity: a study protocol for a randomized controlled trial

Background

Multiple chemical sensitivity (MCS) is a condition characterized by recurrent, self-reported symptoms from multiple organ systems, attributable to exposure to a wide range of chemically unrelated substances at low levels. The pathophysiology is unknown, and affected individuals generally favor avoidance of the symptom triggering substances as a coping strategy. The impact of MCS on daily life may thus be severe. An intervention that may effectively reduce the impact of MCS, alleviate the symptoms and the psychological distress associated with the condition is therefore highly needed. In this study we will assess the effects of a mindfulness-based cognitive (MBCT) program on MCS.

Methods/Design

Using a randomized controlled design (RCT), we will compare MBCT with treatment as usual (TAU). The MBCT intervention will include 8 weekly 2.5 hour sessions, and 45 minutes of mindfulness home practice 6 days each week. Participants will be asked to complete questionnaires at baseline, post-treatment, and at 6 and 12 months’ follow-up. Based on sample size estimation, 82 participants will be randomized to either the MBCT intervention or to TAU. The primary outcome will be a measure of the impact of MCS on the participants’ lives. The secondary outcome measures are physical symptoms of psychological distress, perceived stress, illness perceptions, QOL, and work ability. Lastly, we will assess whether any effect of MBCT on the primary effect measure is mediated by level of mindfulness, self-compassion, perceived stress, and rumination.

Discussion

This trial will provide important information on the effects of MBCT on MCS.

Trials registration

Clinical trials identifier NCT01240395

Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF): a systematic review of identifying criteria

BACKGROUND

Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) remains a complex and unclear phenomenon, often characterized by the report of various, non-specific physical symptoms (NSPS) when an EMF source is present or perceived by the individual. The lack of validated criteria for defining and assessing IEI-EMF affects the quality of the relevant research, hindering not only the comparison or integration of study findings, but also the identification and management of patients by health care providers. The objective of this review was to evaluate and summarize the criteria that previous studies employed to identify IEI-EMF participants.

METHODS

An extensive literature search was performed for studies published up to June 2011. We searched EMBASE, Medline, Psychinfo, Scopus and Web of Science. Additionally, citation analyses were performed for key papers, reference sections of relevant papers were searched, conference proceedings were examined and a literature database held by the Mobile Phones Research Unit of King's College London was reviewed.

RESULTS

Sixty-three studies were included. "Hypersensitivity to EMF" was the most frequently used descriptive term. Despite heterogeneity, the criteria predominantly used to identify IEI-EMF individuals were: 1. Self-report of being (hyper)sensitive to EMF. 2. Attribution of NSPS to at least one EMF source. 3. Absence of medical or psychiatric/psychological disorder capable of accounting for these symptoms 4. Symptoms should occur soon (up to 24 hours) after the individual perceives an exposure source or exposed area. (Hyper)sensitivity to EMF was either generalized (attribution to various EMF sources) or source-specific. Experimental studies used a larger number of criteria than those of observational design and performed more frequently a medical examination or interview as prerequisite for inclusion.

CONCLUSIONS

Considerable heterogeneity exists in the criteria used by the researchers to identify IEI-EMF, due to explicit differences in their conceptual frameworks. Further work is required to produce consensus criteria not only for research purposes but also for use in clinical practice. This could be achieved by the development of an international protocol enabling a clearly defined case definition for IEI-EMF and a validated screening tool, with active involvement of medical practitioners.

Factors associated with prospective development of environmental annoyance

OBJECTIVES

Idiopathic environmental intolerance (IEI) has in cross-sectional studies been associated with emotional problems and psychiatric disorders. However, in the absence of prospective studies it has not been possible to determine whether emotional problems precede the onset of IEI, or are a consequence of IEI. The purpose of this study was to address this issue in a prospective panel study design.

METHODS

The study sample (n=10 275) responded to a postal survey that included five questions regarding annoyance from environmental factors, at baseline and at follow-up five years later. Associations between a number of self-rating scales of stress, subjective health, and working conditions at baseline on one hand, and development of environmental annoyance from baseline to follow-up on the other, were examined.

RESULTS

Participants having developed environmental annoyance between baseline and follow-up had at baseline reported more subjective health complaints, higher levels of stress, strain, and lack of recovery, more dissatisfaction with their work situation, and lower personal social support, compared to participants not developing environmental annoyance.

CONCLUSION

Elevated subjective health complaints, high stress in daily life and a strained work situation, all possible signs of sustained arousal, increase the risk of developing annoyance to environmental factors. The results fit the hypothesis that reduced subjective health, over the course of time, may be attributed to environmental factors.

The approach to the difficult patient

Specific patient and physician characteristics may contribute to a perception that a particular headache patient is "difficult." Headache patients with psychiatric pathology, multiple unexplained symptoms, substance abuse problems, or refractory headaches are commonly perceived as challenging to manage. Physicians who are younger, under more stress, and who do not use collaborative treatment models are more likely to find patients difficult. General principles that may be helpful in coping with headache patients perceived as difficult include: (1) evaluation for possible psychiatric or substance abuse problems with institution of specific treatment if found; (2) a shift in treatment philosophy away from a goal of cure toward a goal of management; (3) the use of written agreements that outline conditions of treatment, including medication amounts; and (4) an integrated, multimodality treatment approach including behavioral and non-pharmacological treatment.

Impact of self-reported multiple chemical sensitivity on everyday life: a qualitative study

BACKGROUND

Multiple chemical sensitivity (MCS) is a descriptive term covering symptoms attributed to exposure to common airborne chemicals. There are no internationally accepted criteria, but it has been suggested that MCS is a chronic and disabling condition. However, details of the impact of MCS on everyday life are limited.

OBJECTIVE

To describe the impact of MCS on everyday life, strategies for managing the condition, and experiences with healthcare management.

METHODS

A focus group study was conducted, including two interviews with a sample of six women and six men between 27 and 78 years of age, a duration of MCS of at least 1 year, and with different occupational conditions.

RESULTS

MCS may severely influence different aspects of everyday life, including lifestyle, social relations, and occupational conditions. Avoiding common airborne chemicals was the most prevalent coping strategy, which implied creating a chemical-free living space and limiting social activities. Experiences with healthcare management were overall reported as negative in terms of not receiving acknowledgement of the reported symptoms.

CONCLUSIONS

MCS may have serious implications for daily functioning. Further research on individual consequences and the social and psychological factors that may be associated with MCS is needed in order to add to our understanding of this condition and to the provision of more satisfactory healthcare.

Abnormalities in cognitive-emotional information processing in idiopathic environmental intolerance and somatoform disorders

Idiopathic environmental intolerance (IEI) represents a functional somatic syndrome marked by diverse bodily complaints attributed to various substances in the environment. Evidence for abnormalities in affective information processing similar to somatoform disorders (SFD) has recently been found in people with IEI. In order to further investigate these cognitive-emotional abnormalities, we compared people with IEI (n=49), SFD only (n=43), and non-somatoform controls (n=54) with respect to their performance in the extrinsic affective Simon task (EAST). This task allowed us to dissociate indicators of automatic affective associations and emotional intrusion effects of both bodily complaints and IEI-trigger words. Negative association effects toward IEI-trigger words were strongest for IEI participants. Emotional intrusion effects of symptom words were larger both in IEI and SFD than in controls. The results of enhanced negative automatic evaluations of IEI-trigger words and greater attention allocation to symptom words support cognitive models of IEI.

Modern health worries and idiopathic environmental intolerance

OBJECTIVE

We conducted two studies to test whether modern health worries (MHWs) were associated with central features of a condition called idiopathic environmental intolerance (IEI) and medical care utilization.

METHODS

In Study 1, 474 Internet users completed an Internet-based questionnaire that assessed MHWs, IEI features, and medical care utilization. In Study 2, the diagnostic specificity of MHWs was investigated by comparing the level of MHWs of three diagnostic groups: 46 people with IEI, 38 people with somatoform disorder but without IEI, and 46 people with neither IEI nor somatoform disorder.

RESULTS

The good psychometric properties of the MHW scale were confirmed. MHWs were related to various features of IEI, and people who met IEI case criteria showed consistently higher levels of MHWs compared with people without IEI. The link between MHWs and number of doctor visits was mediated by perceived IEI complaints. In Study 2, the MHW scale effectively discriminated the IEI group from the non-IEI groups.

CONCLUSIONS

These results suggest that MHWs may contribute to the development of IEI. However, only prospective longitudinal studies will enable us to determine the predictive importance of MHWs for later development of IEI.

The German Multicentre Study on Multiple Chemical Sensitivity (MCS)

In this multicentre study on multiple chemical sensitivity (MCS) 291 consecutive environmental medicine (EM) outpatients were examined in several environmental medicine outpatient centres/units throughout Germany in 2000/2003. Of the EM outpatients, 89 were male (30.6%) and 202 were female (69.4%), aged 22-80 (mean 48 years, S.D.=12 years). The sample was representative for university-based environmental outpatient departments and represented a cross-sectional study design with an integrated clinical-based case-control comparison (MCS vs. non-MCS). Three classifications of MCS were used: self-reported MCS (sMCS), clinically diagnosed MCS (cMCS), and formalised computer-assisted MCS with two variants (f1MCS, f2MCS). Data were collected by means of an environmental medicine questionnaire, psychosocial questionnaires, the German version of the Composite International Diagnostic Interview (CIDI), and a medical baseline documentation, as well as special examinations in partial projects on olfaction and genetic susceptibility markers. The hypothesis guided evaluation of the project showed that the patients' heterogenic health complaints did not indicate a characteristic set of symptoms for MCS. No systematic connection could be observed between complaints and the triggers implicated, nor was there any evidence for a genetic predisposition, or obvious disturbances of the olfactory system. The standardised psychiatric diagnostics applying CIDI demonstrated that the EM patients in general and the subgroup with MCS in particular suffered more often from mental disorders compared to an age and gender matched sample of the general population and that in most patients these disorders commenced many years before environment-related health complaints. Our results do not support the assumption of a toxicogenic-somatic basis of the MCS phenomenon. In contrast, numerous indicators for the relevance of behavioural accentuations, psychic alterations or psychosomatic impairments were found in the group of EM-outpatients with subjective "environmental illness".

Clinical observation of 12 farmers who believe themselves to have suffered from chronic pesticide intoxication

BACKGROUND/AIM

We assessed twelve cases of suspected chronic pesticide intoxication, with medically unexplained physical symptoms.

METHODS

Complete blood cell count (CBC), blood chemistry, routine urinalysis, chest X-ray, ECG, gastrofiberscopy, abdominal ultrasonography, neuroselective sensory nerve conduction threshold, and psychological assessment were performed on 12 farmers who believe themselves to have suffered from chronic pesticide intoxication.

RESULTS

No specific abnormalities were observed on CBC, routine urinalysis, chest X-ray, ECG, gastroscopy, abdominal ultrasonography, or peripheral nerve conduction velocity test. They persistently manifested helplessness, depression, and anxiety. The results of both psychological assessment and general physical examination revealed the following clinical features: depression (8 cases), multiple chemical hypersensitivity syndrome (2 cases), alcoholism (1 case), and religious preoccupation (1 case).

CONCLUSION

In those living in the western rural area of South Korea, depression is a prominent ongoing presentation in pesticide-exposed farmers, in addition to unexplainable physical symptoms.

Evidence for a specific link between the personality trait of absorption and idiopathic environmental intolerance

Absorption as a personality trait refers to the predisposition to get deeply immersed in sensory (e.g., smells, sounds, pictures) or mystical experiences, that is, to experience altered states of consciousness. Absorption is markedly related to constructs openness to experiences, hypnotic suggestibility, imagination, and dissociation. Although absorption was hypothesized to be a risk factor for medically unexplained symptoms (MUS), the construct has yet not been investigated in individually suffering from idiopathic environmental intolerance (IEI), formerly better known as multiple chemical sensitivity (MCS). IEI is a complex condition marked by MUS, which patients attribute to various chemical substances that are typically detectable by their odor (e.g., exhaust emissions, cigarette smoke). The current study investigated whether IEI was related to the personality trait of absorption. In a longitudinal study, 54 subjects with IEI were compared to 44 subjects with a somatoform disorder (SFD), but without IEI, and 54 subjects with neither SFD nor IEI (control group, CG). Self-report measures of somatic symptoms, severity of IEI, and level of absorption were collected both at a first examination and 32 mo later. On both assessments, subjects with IEI and individuals with SFD reported similar highly elevated levels of MUS, compared to CG. In contrast to SFD, IEI was specifically related to elevated absorption scores. IEI was specifically associated with a tendency to experience self-altering states of consciousness. Since absorption is related to both openness to unusual experiences and elevated imaginative involvement, absorption might contribute to IEI via two routes by (1) enhancing the susceptibility for IEI-specific convictions and (2) fostering classical conditioning processes of MUS via enhanced cognitive-imaginative representations of assumed IEI triggers.

Moderne Gesundheitssorgen und ihre Beziehung zu umweltbezogenen Beschwerden

Zusammenfassung. Theoretischer Hintergrund: Nach Petrie und Wessely (2002) bedeuten neue Technologien (z.B. Mobiltelefone und gentechnologisch veränderte Nahrungsmittel) neue Gesundheitssorgen und -beschwerden. Diese modernen Gesundheitssorgen können mittels Fragebogen standardisiert erfasst werden. Fragestellung: Es wurden die Faktorenstruktur, Reliabilität und Validität einer deutschen Übersetzung der Modern Health Worries (MHW) Scale sowie deren Beziehung zu einem funktionellen umweltbezogenen Syndrom, der Idiopathischen Umweltintoleranz (IUI), untersucht. Methode: 757 Studenten einer deutschen Universität füllten Fragebögen zur Erfassung von MHW, IUI, Krankheitsangst, Depressivität und multiplen körperlichen Beschwerden aus. Ergebnisse: Die vier Subskalen der MHW-Skala - Umweltgifte, Umweltverschmutzung, belastete Nahrungsmittel und elektrische Strahlung - konnten faktorenanalytisch bestätigt werden. Die interne Konsistenz (Cronbach’s α) der Subkalen erreichte Werte zwischen .77 und .89. MHW, negativer Affekt und Somatisierungsneigung trugen als unabhängige Prädiktoren jeweils signifikant zur Vorhersage des IUI-Beschwerdeniveaus bei. Schlussfolgerungen: Die deutsche Version der MHW-Skala kann als Messinstrument zur Verwendung für wissenschaftliche Zwecke empfohlen werden. Die Implikationen der Befunde für ein psychogenes Modell der IUI werden diskutiert.

Psychological predictors of short- and medium term outcome in individuals with idiopathic environmental intolerance (IEI) and individuals with somatoform disorders

Idiopathic environmental intolerance (IEI), also known as multiple chemical sensitivity (MCS), is defined as a chronic polysymptomatic condition that cannot be explained by an organic disease. Previous studies suggest that IEI may be a variant of somatoform disorders (SFD), because both disorders overlap with respect to symptoms and psychological features of somatization. However, little is known about the short- and medium-term outcome of IEI and psychological outcome predictors. Two clinical groups (IEI and SFD) and a comparison group (CG) were followed through 32 mo to assess both the outcome, and the extent to which trait anxiety and somatic symptom attribution (assessed at first examination) predict outcome presented 12 and 32 mo later. Outcome measures were the number of self-reported IEI symptoms, IEI triggers, IEI-associated functional impairments, and the number of somatoform symptoms. In addition, the course of the 2 syndromes over the 32-mo follow-up period was investigated with standardized screening scales. The 3 diagnostic groups consisted of 46 subjects with IEI, 38 subjects with SFD but without IEI, and 46 subjects (CG) with neither IEI nor SFD. Syndrome stability was high over the 32-mo follow-up period, and at both follow-ups IEI and non-IEI subjects differed on all IEI outcome measures (symptoms, triggers, functional impairments). Both trait anxiety and somatic attribution (the tendency to attribute common somatic complaints to an illness) predicted outcome. In addition, somatic attribution was found to partially mediate the effect of trait anxiety on outcome in the IEI group. In conclusion, these results suggest that IEI is a chronic and disabling condition and that trait anxiety contributes to the maintenance of the disorder via somatic attributions.

Trauma experience in individuals with idiopathic environmental intolerance and individuals with somatoform disorders

OBJECTIVE

Results from previous studies suggest that past trauma experience increases the risk for medically unexplained somatic symptoms and somatoform disorders (SFD). This cross-sectional study examined the link between various lifetime traumas, idiopathic environmental intolerance (IEI), and SFD.

METHODS

Two clinical groups of 54 subjects with IEI and 44 subjects with SFD were compared to 54 subjects (comparison group, CG) free from both IEI and SFD regarding self-reported traumas. The subjects were mainly recruited via advertisements in local newspapers. From 970 individuals screened for IEI and multiple somatic symptoms, 152 were included through a two-step selection procedure consisting of screening questionnaires, a medical examination, and structured interviews for IEI and mental disorders.

RESULTS

In all three groups at least one potential traumatic event was reported rather frequently (CG: 70%; IEI: 82%; SFD: 73%). But contrary to our expectation, significant group differences were neither found in regard to the proportion of subjects with any trauma, nor traumas fulfilling DSM-IV criteria (CG: 41%; IEI: 48%; SFD: 59%), nor multiple traumas (CG: 43%, IEI: 56%, SFD: 39%). Only two trauma categories were endorsed more frequently by the two clinical groups than by the CG: the unspecified 'other' category (IEI, SFD>CG) and 'life-threatening illness' (IEI>CG).

CONCLUSION

No clear evidence was found for increased rates of trauma experience in IEI and SFD. However, the results of this exploratory study should be considered as preliminary. Comparing larger IEI and SFD groups with a representative population-based sample may yield different results.