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

Multiple Chemical Sensitivity: It's time to catch up to the science

Multiple chemical sensitivity (MCS) is a complex medical condition associated with low dose chemical exposures. MCS is characterized by diverse features and common comorbidities, including fibromyalgia, cough hypersensitivity, asthma, and migraine, and stress/anxiety, with which the syndrome shares numerous neurobiological processes and altered functioning within diverse brain regions. Predictive factors linked to MCS comprise genetic influences, gene-environment interactions, oxidative stress, systemic inflammation, cell dysfunction, and psychosocial influences. The development of MCS may be attributed to the sensitization of transient receptor potential (TRP) receptors, notably TRPV1 and TRPA1. Capsaicin inhalation challenge studies demonstrated that TRPV1 sensitization is manifested in MCS, and functional brain imaging studies revealed that TRPV1 and TRPA1 agonists promote brain-region specific neuronal variations. Unfortunately, MCS has often been inappropriately viewed as stemming exclusively from psychological disturbances, which has fostered patients being stigmatized and ostracized, and often being denied accommodation for their disability. Evidence-based education is essential to provide appropriate support and advocacy. Greater recognition of receptor-mediated biological mechanisms should be incorporated in laws, and regulation of environmental exposures.

Psychological models of development of idiopathic environmental intolerances: Evidence from longitudinal population-based data

The origin of idiopathic environmental intolerances (IEIs) is an open question. According to the psychological approaches, various top-down factors play a dominant role in the development of IEIs. The general psychopathology model assumes a propensity towards mental ill-health (negative affectivity) increases the probability of developing IEIs. The attribution model emphasizes the importance of mistaken attribution of experienced somatic symptoms; thus, more symptoms should lead to more IEIs. Finally, the nocebo model highlights the role of expectations in the development of IEIs. In this case, worries about the harmful effects of environmental factors are assumed to evoke IEIs. We estimated cross-lagged panel models with latent variables based on longitudinal data obtained at two time points (six years apart) from a large near-representative community sample to test the hypothesized associations. Indicators of chemical intolerance, electromagnetic hypersensitivity, and sound sensitivity fit well under a common latent factor of IEIs. This factor, in turn, showed considerable temporal stability. However, whereas a positive association was found between IEIs and increased somatic symptoms and modern health worries six years later, the changes therein could not be predicted as hypothesized by the three psychological models. We discuss the implications of these results, as well as methodological aspects in the measurement and prediction of change in IEIs.

Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.

Is severity a clinically meaningful specifier of somatic symptom disorder?

OBJECTIVE

Few existing studies have investigated the clinical relevance of Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) somatic symptom disorder (SSD) severity rated by clinicians. We examined the association of SSD severity with psychiatric and medical comorbidity, psychological features and help-seeking attitude and behaviours.

METHODS

A total of 123 patients with SSD were prospectively recruited and completed several types of self-report instrument. Information about medical comorbidity and healthcare use was gathered from the participants and medical record review. Common comorbid psychiatric diagnoses of SSD were assessed by psychiatrists. Group differences of patients with SSD of varying severity were assessed with ANOVA and chi-square tests. Multiple linear regression models were used to examine the relationships between SSD severity and psychological features.

RESULTS

Prevalence of medical comorbidity and comorbid psychiatric diagnoses of SSD was not significantly different among patients with varying SSD severity. Patients with severe SSD had the highest Patient Health Questionnaire-15 (PHQ-15), Health Anxiety Questionnaire (HAQ), Beck Depression Inventory-II (BDI-II) and Beck Anxiety Inventory (BAI) scores. Help-seeking behaviour was not associated with SSD severity. After controlling for demographic variables, the associations between 'severe SSD' and the PHQ-15, HAQ, BDI-II and BAI scores were significant.

CONCLUSION

SSD severity rated by clinicians was not associated with comorbid medical or psychiatric diagnoses. Compared to patients with mild/moderate SSD, patients with severe SSD not only had higher somatic distress and health anxiety but also higher levels of anxiety/depression. However, SSD severity was not associated with help-seeking attitude and behaviour.

Psychosocial treatments for employees with non-specific and persistent physical symptoms associated with indoor air: A randomised controlled trial with a one-year follow-up

OBJECTIVE

Persistent physical symptoms (PPS) associated with indoor air without an adequate pathophysiological- or environmental-related explanation may lead to work disability and decreased health-related quality of life (HRQoL). We attempted to assess the effect of cognitive behavioural therapy (CBT) for PPS and also psychoeducation (PE) on these symptoms involving disability.

METHOD

The intention-to-treat (ITT) sample included 52 employees recruited from an occupational healthcare service randomised as either controls undergoing treatment as usual (TAU) or TAU enhanced with CBT or PE. The primary outcome was HRQoL measuring the severity of symptoms and restrictions in everyday life caused by them. Secondary outcomes included depressive, anxiety and insomnia symptoms, and intolerance to environmental factors, assessed at baseline and at 3-, 6- and 12-month follow-ups.

RESULTS

At the 12-month follow-up assessment point, no statistically significant differences between treatments emerged following adjustment for gender, age, and HRQoL before the waiting period in the ITT analysis [F(2,46)=2.89, p=.07]. The secondary analysis revealed a significant improvement in HRQoL in the combined intervention group as compared with controls [F(1,47)=5.06, p=.03, g=0.41]. In total, 15% of participants dropped out during follow-up.

CONCLUSIONS

The results suggest that CBT for PPS or PE might not have a robust effect on HRQoL in PPS associated with indoor air, but the study did not achieve the planned power. Despite difficulties during the recruitment process, the final dropout rates remained low, and participants positively evaluated CBT, suggesting that it represents an acceptable treatment to them. Trial status This study was registered at the ClinicalTrials.gov registry (NCT02069002).

Multiple Chemical Sensitivity: Review of the State of the Art in Epidemiology, Diagnosis, and Future Perspectives

OBJECTIVE

Systematic bibliography analysis of about the last 17 years on multiple chemical sensitivity (MCS) was carried out in order to detect new diagnostic and epidemiological evidence. The MCS is a complex syndrome that manifests as a result of exposure to a low level of various common contaminants. The etiology, diagnosis, and treatment are still debated among researchers.

METHOD

Querying PubMed, Web of Science, Scopus, Cochrane library, both using some specific MESH terms combined with MESH subheadings and through free search, even by Google.

RESULTS

The studies were analyzed by verifying 1) the typology of study design; 2) criteria for case definition; 3) presence of attendances in the emergency departments and hospital admissions, and 4) analysis of the risk factors.

OUTLOOK

With this review, we give some general considerations and hypothesis for possible future research.

Modern health worries: Deriving two measurement invariant short scales for cross-cultural research with Ant Colony Optimization

Worries about possible harmful effects of new technologies (modern health worries) have intensely been investigated in the last decade. However, the comparability of translated self-report measures across countries is often problematic. This study aimed to overcome this problem by developing psychometrically sound brief versions of the widely used 25-item Modern Health Worries Scale (MHWS) suitable for multi-country use. Based on data of overall 5,176 individuals from four European countries (England, Germany, Hungary, Sweden), Ant Colony Optimization was used to identify the indicators that optimize model fit and measurement invariance across countries. Two scales were developed. A short (12-item) version of the MHWS that represents the four-factor structure of the original version and an ultra-short (4-item) scale that only measures the general construct. Both scales show that overall levels of health worries were highest in England and Hungary, but that the main reason for concern (e.g. electromagnetic radiation or food related fears) differs considerably between these countries. This study also shows that even if measurement invariance of translated self-report instruments across countries is problematic, it can be optimized by using adequate item selection procedures. Differences of modern health worries across countries and recommendations for cross-cultural research are discussed.

Predicting the course of persistent physical symptoms: Development and internal validation of prediction models for symptom severity and functional status during 2 years of follow-up

OBJECTIVE

Increased knowledge about predictors of the course of persistent physical symptoms (PPS) is needed to identify patients at risk for long-term PPS in clinical settings. Therefore, we developed prediction models for the course of PPS in terms of symptom-severity and related functional status during a 2-year follow-up period.

METHODS

We used data of the PROSPECTS cohort study, consisting of 325 PPS patients from several health care settings. Symptom severity (PHQ-15), physical functioning (RAND 36 PCS) and mental functioning (RAND 36 MCS) were assessed at baseline and 6, 12 and 24 months afterwards. We applied mixed model analyses to develop prediction models for all outcomes, using all follow-up measurements. Potential predictors were based on empirical and theoretical literature and measured at baseline.

RESULTS

For symptom severity, physical functioning and mental functioning we identified predictors for the adverse course of PPS included physical comorbidity, higher severity and longer duration of PPS at baseline, anxiety, catastrophizing cognitions, embarrassment and fear avoidance cognitions, avoidance or resting behaviour and neuroticism. Predictors of a favourable course included limited alcohol use, higher education, higher levels of physical and mental functioning at baseline, symptom focusing, damage cognitions and extraversion. Explained interpersonal variance for all three models varied between 70.5 and 76.0%. Performance of the models was comparable in primary and secondary/tertiary care.

CONCLUSION

The presented prediction models identified several relevant demographic, medical, psychological and behavioural predictors for adverse and favourable courses of PPS. External validation of the presented models is needed prior to clinical implementation.

The association between multiple chemical sensitivity and mental illness: Evidence from a nationally representative sample of Canadians

OBJECTIVE

The goal of the present study was to investigate the association between multiple chemical sensitivity (MCS) and major depressive disorder (MDD), generalized anxiety disorder (GAD), MDD and GAD comorbidity (MDD+GAD), severe distress, and positive mental wellbeing.

METHODS

This cross-sectional investigation was carried out using the 2012 Canadian Community Health Survey - Mental Health Component. The study population consisted of 21,977 individuals aged 20 and older, from Canada's ten provinces. Odds ratios were computed using multinomial logistic regression to calculate estimates of the association between MCS and mental illness. All analyses were weighted to take into account the complex survey design.

RESULTS

Individuals with MCS had 2.37 (1.55, 3.64) times greater odds of MDD, 3.09 (1.80, 5.30) times greater odds of MDD+GAD, and 2.60 (1.67, 4.07) times greater odds of severe distress. No association between MCS and GAD was observed. A sex difference was observed with males with MCS having lower odds of positive mental wellbeing, whereas no association was observed in females.

CONCLUSIONS

The present study findings supported an association between MCS and mental illness. The causal mechanism supporting this association remains unclear.

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.

Long-Term Follow-Up in Patients With Airway Chemical Intolerance

OBJECTIVE

A 5-year follow-up study showed that a group of patients with airway symptoms from chemicals and scents had lasting symptoms, together with enduring increased capsaicin cough sensitivity. The aim was to follow up the same patients after another 5 years.

METHODS

All previously participants were invited for an additional follow-up. They visited the clinic twice; at one opportunity, they undertook a capsaicin inhalation provocation, and at the other, a methacholine provocation, and answered various questionnaires.

RESULTS

Sixteen patients attende the study after a median of 8 years. They reported unchanged symptoms from chemicals and scents; the capsaicin cough sensitivity was still increased, and the repeatability for the capsaicin inhalation was good.

CONCLUSIONS

Airway symptoms induced by chemicals and scents constitute a chronic disease, with unchanged trigger factors, persistent symptoms, and unchanged, long-lasting sensory hyperreactivity.All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.This study was supported by grants from the Herman Krefting Foundation Against Asthma/Allergy, the Swedish Heart and Lung Foundation, and the Swedish Cancer and Allergy Fund.

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.

Comparing cognitive-behavioural psychotherapy and psychoeducation for non-specific symptoms associated with indoor air: a randomised control trial protocol

INTRODUCTION

Indoor air-related conditions share similarities with other conditions that are characterised by medically unexplained symptoms (MUS)-a combination of non-specific symptoms that cannot be fully explained by structural bodily pathology. In cases of indoor air-related conditions, these symptoms are not fully explained by either medical conditions or the immunological-toxicological effects of environmental factors. The condition may be disabling, including a non-adaptive health behaviour. In this multifaceted phenomenon, psychosocial factors influence the experienced symptoms. Currently, there is no evidence of clinical management of symptoms, which are associated with the indoor environment and cannot be resolved by removing the triggering environmental factors. The aim of this study is to compare the effect of treatment-as-usual (TAU) and two psychosocial interventions on the quality of life, and the work ability of employees with non-specific indoor air-related symptomatology.

METHODS AND ANALYSES

The aim of this ongoing randomised controlled trial is to recruit 60 participants, in collaboration with 5 occupational health service units. The main inclusion criterion is the presence of indoor air-related recurrent symptoms in ≥2 organ systems, which have no pathophysiological explanation. After baseline clinical investigations, participants are randomised into interventions, which all include TAU: cognitive-behavioural psychotherapy, psychoeducation and TAU (control condition). Health-related quality of life, measured using the 15D-scale, is the primary outcome. Secondary outcomes include somatic and psychiatric symptoms, occupational factors, and related underlying mechanisms (ie, cognitive functioning). Questionnaires are completed at baseline, at 3, 6 and 12-month follow-ups. Data collection will continue until 2017. The study will provide new information on the individual factors related to indoor air-associated symptoms, and on ways in which to support work ability.

ETHICS AND DISSEMINATION

The Coordinating Ethics Committee of the Hospital District of Helsinki and Uusimaa, Finland, has granted approval for the study. The results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02069002; Pre-results.

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.

Investigation of facial emotion recognition, alexithymia, and levels of anxiety and depression in patients with somatic symptoms and related disorders

BACKGROUND

The concept of facial emotion recognition is well established in various neuropsychiatric disorders. Although emotional disturbances are strongly associated with somatoform disorders, there are a restricted number of studies that have investigated facial emotion recognition in somatoform disorders. Furthermore, there have been no studies that have regarded this issue using the new diagnostic criteria for somatoform disorders as somatic symptoms and related disorders (SSD). In this study, we aimed to compare the factors of facial emotion recognition between patients with SSD and age- and sex-matched healthy controls (HC) and to retest and investigate the factors of facial emotion recognition using the new criteria for SSD.

PATIENTS AND METHODS

After applying the inclusion and exclusion criteria, 54 patients who were diagnosed with SSD according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria and 46 age- and sex-matched HC were selected to participate in the present study. Facial emotion recognition, alexithymia, and the status of anxiety and depression were compared between the groups.

RESULTS

Patients with SSD had significantly decreased scores of facial emotion for fear faces, disgust faces, and neutral faces compared with age- and sex-matched HC (t=-2.88, P=0.005; t=-2.86, P=0.005; and t=-2.56, P=0.009, respectively). After eliminating the effects of alexithymia and depressive and anxious states, the groups were found to be similar in terms of their responses to facial emotion and mean reaction time to facial emotions.

DISCUSSION

Although there have been limited numbers of studies that have examined the recognition of facial emotion in patients with somatoform disorders, our study is the first to investigate facial recognition in patients with SSD diagnosed according to the DSM-5 criteria. Recognition of facial emotion was found to be disturbed in patients with SSD. However, our findings suggest that disturbances in facial recognition were significantly associated with alexithymia and the status of depression and anxiety, which is consistent with the previous studies. Further studies are needed to highlight the associations between facial emotion recognition and SSD.

Differential odor sensitivity in PTSD: Implications for treatment and future research

BACKGROUND

Given that odors enhance the retrieval of autobiographical memories, induce physiological arousal, and trigger trauma-related flashbacks, it is reasonable to hypothesize that odors play a significant role in the pathophysiology of posttraumatic stress disorder (PTSD). For these reasons, this preliminary study sought to examine self-reported, odor-elicited distress in PTSD.

METHODS

Combat veterans with (N=30) and without (N=22) PTSD and healthy controls (HC: N=21), completed an olfactory questionnaire that provided information on the hedonic valence of odors as well as their ability to elicit distress or relaxation.

RESULTS

Two main findings were revealed: Compared to HC, CV+PTSD, but not CV-PTSD, reported a higher prevalence of distress to a limited number of select odors that included fuel (p=.004), blood (p=.02), gunpowder (p=.03), and burning hair (p=.02). In contrast to this increased sensitivity, a blunting effect was reported by both groups of veterans compared to HC that revealed lower rates of distress and relaxation in response to negative hedonic odors (p=.03) and positive hedonic odors (p<.001), respectively.

LIMITATIONS

The study is limited by its use of retrospective survey methods, whereas future investigations would benefit from laboratory measures taken prior, during, and after deployment.

CONCLUSION

The present findings suggest a complex role of olfaction in the biological functions of threat detection. Several theoretical models are discussed. One possible explanation for increased sensitivity to select odors with decreased sensitivity to other odors is the co-occurrence of attentional bias toward threat odors with selective ignoring of distractor odors. Working together, these processes may optimize survival.

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.

Negative affect is associated with development and persistence of chemical intolerance: a prospective population-based study

OBJECTIVE

Chemical intolerance (CI) is characterised by negative health effects attributed to a heightened responsiveness to common airborne chemicals. This longitudinal study explored the hypothesised role of negative affect in the development and persistence of CI in a general population.

METHODS

A general population sample aged 19 to 72 years was examined in 2006-2008 and again in 2011-2012. Longitudinal data on CI were analysed with the purpose of examining baseline negative affect as a risk factor for having developed CI at 5-year follow-up and for reporting persistent CI. Participants were classified as reporting no signs of CI, having symptoms of CI and as being a likely CI case based on self-reported reactions to 11 common chemical exposures, symptoms related to chemical exposures and daily life adjustments attributed to reactions when exposed to chemicals.

RESULTS

A total of 69.4% of the participants who had reported CI at baseline also reported CI at follow-up. In participants with no baseline CI, 15.5% reported CI at follow-up and 18.1% reported symptoms related to chemicals but no daily life adjustments. Baseline negative affect was positively and statistically significantly associated with both development and persistence of CI.

CONCLUSIONS

Initial reports of CI were found to be persistent over time, and a considerable proportion of the participants with no CI at baseline reported having developed CI after 5 years. The positive association between negative affect and CI at the 5-year follow-up supports negative affect as a possible risk factor for CI.

Physical symptom attributions: a defining characteristic of somatoform disorders?

OBJECTIVES

We examined whether primary care patients were more likely to perceive a current health problem as 'physical illness only' as opposed to entailing psychological difficulties if they had a comorbid somatoform disorder compared to patients who had (a) both comorbid somatoform disorder and anxiety/depression or (b) comorbid anxiety and/or depression, and a reference group of (c) patients with well-defined physical disease. We examined whether attributions predicted future health expenditures.

METHODS

A total of 1209 of 1785 patients completed questions on patient-perceived illness. The physicians diagnosed the current health problem. A stratified subsample was interviewed using the Schedules for Clinical Assessment in Neuropsychiatry. Health expenditure was obtained from registers for a 2-year period.

RESULTS

The belief that the current health problem was only physical was endorsed by 86% of patients presenting physical disease, 58% of patients with somatoform disorders, 29% of patients with both somatoform disorders and anxiety/depression and 24% of patients with anxiety or depressive disorders (χ2=269.2, df=3, P<.0001). In a multiple regression model, a 'physical illness only' perception predicted lower health expenditures [β = -0.31, 95% confidence interval (-0.55; -0.07), P=.013].

CONCLUSIONS

The prevalent assumption that physical symptom attributions are a central aspect in somatoform disorders is not supported by the current study.

Odor and noise intolerance in persons with self-reported electromagnetic hypersensitivity

Lack of confirmation of symptoms attributed to electromagnetic fields (EMF) and triggered by EMF exposure has highlighted the role of individual factors. Prior observations indicate intolerance to other types of environmental exposures among persons with electromagnetic hypersensitivity (EHS). This study assessed differences in odor and noise intolerance between persons with EHS and healthy controls by use of subscales and global measures of the Chemical Sensitivity Scale (CSS) and the Noise Sensitivity Scale (NSS). The EHS group scored significantly higher than the controls on all CSS and NSS scales. Correlation coefficients between CSS and NSS scores ranged from 0.60 to 0.65 across measures. The findings suggest an association between EHS and odor and noise intolerance, encouraging further investigation of individual factors for understanding EMF-related symptoms.

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.

Descriptive and predictive validity of somatic attributions in patients with somatoform disorders: a systematic review of quantitative research

OBJECTIVE

Research on hypochondriasis and other somatoform disorders (SFD) has provided evidence that patients with SFD tend to attribute their symptoms to organic dysfunctions or disease. However, recent studies appear to discredit this. There is no systematic evidence on whether patients with SFD predominantly rely on somatic attributions, despite calls to include somatic attributions as a positive criterion of somatic symptom disorder (SSD) in the upcoming Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

METHODS

This study is a systematic review of quantitative studies which assess the descriptive and predictive validity of somatic attribution in SFD. The literature search was restricted to studies with patients who met the DSM-IV criteria for SFD.

RESULTS

Somatic attribution style in SFD has acceptable descriptive but insufficient predictive validity. This confirms that the overlap between somatic and psychological attributions is often substantial. Attribution style can discriminate between SFD patients with and without comorbidity.

CONCLUSION

A somatic attribution style does not qualify as a positive criterion in SSD. However, there is an urgent need for further research on causal illness perceptions in the full spectrum of medically unexplained symptoms in order to confirm this result. Given its high prevalence, research on psychological attribution style is warranted. Re-attribution does not provide a framework sophisticated enough to address the needs of patients in primary care.

Transcranial pulsed electromagnetic fields for multiple chemical sensitivity: study protocol for a randomized, double-blind, placebo-controlled trial

Background

Multiple chemical sensitivity (MCS) is a chronic condition of unknown etiology. MCS is characterized by recurrent nonspecific symptoms from multiple organ systems in response to chemical exposures in concentrations that are normally tolerated by the majority of the population. The symptoms may have severe impact on patients’ lives, but an evidence-based treatment for the condition is nonexisting. The pathophysiology is unclarified, but several indicators point towards abnormal processing of sensory signals in the central nervous system. Pulsed electromagnetic fields (PEMF) offer a promising new treatment for refractory depression and can be targeted at the brain, thereby activating biochemical cell processes.

Methods/Design

In a parallel, randomized, double-blind, placebo-controlled trial conducted at the Danish Research Centre for Chemical Sensitivities, the effects of PEMF in MCS patients will be assessed using the Re5 Independent System. Based on sample size estimation, 40 participants will be randomized to either PEMF therapy or placebo. The allocation sequence will be generated by computer. All involved parties (that is, participants, investigators, the research nurse, and the statistician) will be blinded to group allocation. The participants will receive PEMF therapy or placebo applied transcranially 30 minutes twice a day for 7 days a week over 6 consecutive weeks. Outcomes will be measured at baseline, once weekly during treatment, post treatment, and at 2.5-month and 4.5-month follow-up according to a predefined timetable. The primary outcome will be a measurement of the impact of MCS on everyday life. The secondary outcomes will be measurements of MCS symptoms, psychological distress (stress, anxiety or depressive symptoms), capsaicin-induced secondary punctate hyperalgesia, immunological markers in serum, and quality of life.

Discussion

This trial will assess the effects of PEMF therapy for MCS. Currently, there is no treatment with a documented effect on MCS, and in terms of healthcare there is very little to offer these patients. There is thus a great need for well-conducted randomized trials aimed at assessing possible treatment effects. A positive outcome will pave the way for improved healthcare and understanding of this very disabling and overlooked condition.

Trial registration

ClinicalTrials.gov, NCT01834781

[Pathophysiology of multiple chemical sensitivity]

INTRODUCTION AND BACKGROUND

Multiple chemical sensitivity (MCS) is a complex clinical entity that includes a large number of non-specific symptoms, associated in a univocal manner in each patient and triggered by exposure to various chemicals at low concentrations, well below those known to cause toxic effects. However, no objective test exists currently to diagnose this syndrome. One of the main reasons is that the pathophysiology is poorly understood. However, many explanatory hypotheses have been proposed.

VIEWPOINTS AND CONCLUSIONS

Patients with symptoms of MCS are often encountered by pulmonologists. Their suffering is undeniable but, unfortunately, the lack of understanding of the pathophysiological mechanisms makes treatment difficult and empirical.

Construct validity and descriptive validity of somatoform disorders in light of proposed changes for the DSM-5

OBJECTIVE

Current diagnostic criteria for somatoform disorders demand revisions due to their insufficient clinical as well as scientific usability. Various psychological and behavioral characteristics have been considered for the proposed new category Somatic Symptom Disorder (SSD). With this study, we were able to jointly assess the validity of these variables in an inpatient sample.

METHODS

Using a cross-sectional design, we investigated N=456 patients suffering from somatoform disorder, anxiety, or depression. Within one week after admission to the hospital, informed consent was obtained and afterwards, a diagnostic interview and a battery of self-report questionnaires were administered. Logistic regression analyses were performed to determine which variables significantly add to construct and descriptive validity.

RESULTS

Several features, such as somatic symptom severity, health worries, health habits, a self-concept of being weak, and symptom attribution, predicted physical health status in somatization. Overall, our model explained about 50% of the total variance. Furthermore, in comparison with anxious and depressed patients, health anxiety, body scanning, and a self-concept of bodily weakness were specific for DSM-IV somatoform disorders and the proposed SSD.

CONCLUSIONS

The present study supports the inclusion of psychological and behavioral characteristics in the DSM-5 diagnostic criteria for somatoform disorders. Based on our results, we make suggestions for a slight modification of criterion B to enhance construct validity of the Somatic Symptom Disorder.

[Multiple chemical sensitivity: a diagnosis not to be missed]

Multiple chemical sensitivity (MCS) is a chronic condition, which belongs to the group of medically unexplained syndromes. Patients (men as well as women) complain of many subjective symptoms such as nose and mouth irritation, sore throat, dyspnea, tiredness, dizziness, headache and concentration difficulties. Patient typically report at least four or five symptoms occurring when they are exposed to particular substances, at a very low concentration that usually does not cause symptoms or harm in normal individuals. The common feature of products that appear to be responsible (either occupational or domestic) is that they have a strong smell and include: solvent, paint, glue, tar, oil, pesticides, perfume, cosmetics and spray products. MCS is nowadays considered to be one aspect of idiopathic environmental intolerance (IEI) whose other main aspect is hypersensitivity to electromagnetic fields. If the diagnosis is suspected clinically it can be confirmed using the Quick Environmental Exposure and Sensitivity Inventory (QEESI(©)) self-questionnaire. MCS is often misdiagnosed as asthma or an allergic conditions which means that patients are frequently referred to respiratory and allergy specialists. Misdiagnosis can lead to many futile medical investigations. Psychotherapy can improve quality of life in some cases. Preventive measures are often ineffective and do not stop the condition worsening: hypersensitivity can spread to common environmental odors so that a few people become severely disabled and limited in their workplace as well as in private life. In France, 435 cases were registered in the university hospital occupational disease departments network (RNV3P) during the period 2007-2010. It is therefore important that every clinician be able to recognize the condition and ensure that their patients could get compensation when unable to go on working.

Review of evidence for a toxicological mechanism of idiopathic environmental intolerance

Idiopathic environmental intolerance (IEI) is a medically unexplained disorder characterised by a wide variety of unspecific symptoms in different organ systems and attributed to nontoxic concentrations of chemicals and other environmental factors that are tolerated by the majority of individuals. Both exposure to chemicals and behavioural conditioning are considered as possible contributors to the development of IEI. However, owing to the heterogeneity of the condition, it is difficult to separate the toxicological, physiological and psychological aspects of IEI. Here, we review the evidence for postulated toxicologically mediated mechanisms for IEI. Available data do not support either a classical receptor-mediated or an idiosyncratic toxicological mechanism. Furthermore, if there were convincing evidence for a psychological cause for many patients with IEI, then this would suggest that the priority for the future is the development of psychological treatments for IEI. Finally, we advocate genome wide screening of IEI patients to elucidate genotypic features of the condition.

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

The feasibility of aromatherapy massage to reduce symptoms of Idiopathic Environmental Intolerance: a pilot study

OBJECTIVES

Idiopathic Environmental Intolerance (IEI) is an acquired disorder with multiple recurrent symptoms, which is associated with diverse environmental factors that are tolerated by the majority of people. IEI is an illness of uncertain aetiology, making it difficult to treat using conventional medicine. Therefore, there is a need for novel therapies to control the symptoms of IEI. The objective of this study was to evaluate the feasibility and impact of aromatherapy massage for individuals with IEI.

DESIGN

Non-blinded crossover trial.

SETTING

IEI patients who attended a clinic in Sapporo city were recruited, and sixteen patients were enrolled. Participants were clinically examined by an experienced medical doctor and met the criteria included in the working definition of IEI disorder.

INTERVENTIONS

During the active period, participants received four one-hour aromatherapy massage sessions every two weeks. During the control period, the participants did not receive any massages.

MAIN OUTCOME MEASUREMENTS

Scores on the IEI-scales trigger checklist, symptoms, life impact, and the State Anxiety Inventory were assessed before and after each period. Short-term mood enhancement was evaluated using the Profiles of Mood Status (POMS) before and after sessions.

RESULTS

Due to period effects, evaluation of the results had to be restricted to the first period, and the result showed no effect of intervention. All six sub-scales of the POMS improved after each session (mean score differences: 4.89-1.33, P<0.05).

CONCLUSIONS

Aromatherapy was well tolerated by subjects with IEI; however, aromatherapy, as applied in this study, did not suggest any specific effects on IEI condition.

Chemical intolerance in primary care settings: prevalence, comorbidity, and outcomes

PURPOSE

This study extends previous community-based studies on the prevalence and clinical characteristics of chemical intolerance in a sample of primary care clinic patients. We evaluated comorbid medical and psychiatric disorders, functional status, and rates of health care use.

METHODS

A total of 400 patients were recruited from 2 family medicine clinic waiting rooms in San Antonio, Texas. Patients completed the validated Quick Environmental Exposure and Sensitivity Inventory (QEESI) to assess chemical intolerance; the Primary Care Evaluation of Mental Disorders (PRIME-MD) screen for possible psychiatric disorders; the Dartmouth-Northern New England Primary Care Cooperative Information Project (Dartmouth COOP) charts for functional status; and the Healthcare Utilization Questionnaire.

RESULTS

Overall, 20.3% of the sample met criteria for chemical intolerance. The chemically intolerant group reported significantly higher rates of comorbid allergies and more often met screening criteria for possible major depressive disorder, panic disorder, generalized anxiety disorder, and alcohol abuse disorder, as well as somatization disorder. The total number of possible mental disorders was correlated with chemical intolerance scores (P <.001). Controlling for demographics, patients with chemical intolerance were significantly more likely to have poorer functional status, with trends toward increased medical service use when compared with non-chemically intolerant patients. After controlling for comorbid psychiatric conditions, the groups differed significantly only regarding limitations of social activities.

CONCLUSIONS

Chemical intolerance occurs in 1 of 5 primary care patients yet is rarely diagnosed by busy practitioners. Psychiatric comorbidities contribute to functional limitations and increased health care use. Chemical intolerance offers an etiologic explanation. Symptoms may resolve or improve with the avoidance of salient chemical, dietary (including caffeine and alcohol), and drug triggers. Given greater medication intolerances in chemical intolerance, primary care clinicians could use the QEESI to identify patients for appropriate triage to comprehensive nonpharmacologic care.

Evaluation of the quick environmental exposure and sensitivity inventory in a Danish population

Objectives. To evaluate a Danish translation of the Quick Environmental Exposure and Sensitivity Inventory (QEESI). Methods. The study included two groups: one comprised a random sample of 2000 individuals drawn from the Danish Civil Registration System; the other comprised 315 patients with chemical intolerance. Results. The evaluation suggested good reliability for the four QEESI scales in terms of internal consistency and coefficients between test and retest scores. The discriminatory validity was the largest for the Chemical (inhalant) Intolerance and Life Impact Scales. Using combined cut-off scores for these two scales provided a sensitivity of 92.1 and a specificity of 91.8 and yielded a prevalence of 8.2% in the population group. Conclusions. The Danish translation of the QEESI showed overall good reliability and validity. We recommend the use of the combined Chemical (inhalant) Intolerance and Life Impact Scales in future studies.

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.

Repressive coping and alexithymia in idiopathic environmental intolerance

OBJECTIVE

To examine if the non-expression of negative emotions (i.e., repressive coping) and differences in the ability to process and regulate emotions (i.e., alexithymia) is associated with idiopathic environmental intolerance (IEI).

METHODS

The study included participants who had previously participated in a general population-based study and reported symptoms of environmental intolerance (n = 787) and patients with IEI (n = 237). The participants completed questionnaires assessing IEI, namely, a measure of repressive coping combining scores on the Marlowe-Crowne Social Desirability Scale (MCSDS) and the Taylor Manifest Anxiety Scale (TMAS), the Toronto Alexithymia Scale (TAS-20), and a negative affectivity scale (NAS). Multiple, hierarchical linear regression analyses were conducted using IEI variables as the dependent variables.

RESULTS

The TMAS and MCSDS scores were independently associated with the IEI variables, but there was no evidence of a role of the repressive coping construct. While the total alexithymia score was unrelated to IEI, the TAS-20 subscale of difficulties identifying feelings (DIF) was independently associated with symptoms attributed to IEI. Negative affectivity was a strong independent predictor of the IEI variables and a mediator of the association between DIF and IEI.

CONCLUSION

Our results provide no evidence for a role of repressive coping in IEI, and our hypothesis of an association with alexithymia was only partly supported. In contrast, strong associations between IEI and negative emotional reactions, defensiveness and difficulties identifying feelings were found, suggesting a need for exploring the influence of these emotional reactions in IEI.

Attention to bodily sensations and symptom perception in individuals with idiopathic environmental intolerance

INTRODUCTION

Idiopathic environmental intolerance (IEI) is characterized by non-specific symptoms attributed to exposure to environmental odours or chemicals at levels below those known to induce adverse health effects. A clarification of whether psychological processes involved in sensory perceptions are associated with IEI would add to our understanding of this complex disorder.

PURPOSE

To examine if measures of somato-sensory amplification, autonomic perception and absorption are associated with IEI.

METHODS

The study included individuals with self-reported or physician-diagnosed IEI. Participants (n = 732) completed questionnaires that included items on descriptive variables of IEI, the Somato-Sensory Amplification Scale (SSAS), the Autonomic Perception Questionnaire (APQ), the Tellegen Absorption Scale (TAS) and a Negative Affectivity Scale (NAS).

RESULTS

Multiple, hierarchical linear regression analyses revealed significant positive associations between SSAS, APQ, and IEI, while small and inverse associations were seen between TAS and IEI.

CONCLUSIONS

The association with SSAS and APQ suggests that perceptual personality characteristics are important in understanding this disorder.

Evaluation of subjective symptoms of Japanese patients with multiple chemical sensitivity using QEESI(c)

OBJECTIVES

The Quick Environment Exposure Sensitivity Inventory (QEESI(c)) has been used as a questionnaire to evaluate subjective symptoms of patients with multiple chemical sensitivity (MCS), also known as idiopathic environmental intolerance, in Japan. However, no cutoff value for Japanese subjects has yet been established. We designed this study to establish a cutoff value for Japanese subjects using QEESI(c) for screening of MCS patients.

METHODS

A questionnaire using the QEESI(c) was administered to 103 MCS patients and 309 healthy control subjects matched for age and sex. QEESI(c) scores of the two groups were compared using logistic regression analysis, receiver operating characteristic analysis, and the Mann-Whitney test.

RESULTS

Cutoff values for Japanese subjects were determined for the Chemical Intolerance subscale (40), Symptom Severity subscale (20), and Life Impact subscale (10). The subjects whose scores exceeded the cutoff values in any two subscales accounted for 88.4% of the patients but only 14.5% of the controls.

CONCLUSIONS

Our results suggest that subjects meeting two out of three subscale criteria can be screened as "patients suffering from a low level of environmental chemicals such as MCS" in Japan.

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.

General practitioners' experiences with provision of healthcare to patients with self-reported multiple chemical sensitivity

OBJECTIVE

To describe general practitioners' (GPs') evaluation of and management strategies in relation to patients who seek medical advice because of multiple chemical sensitivity (MCS).

DESIGN

A nationwide cross-sectional postal questionnaire survey. The survey included a sample of 1000 Danish GPs randomly drawn from the membership list of GPs in the Danish Medical Association.

SETTING

Denmark.

RESULTS

Completed questionnaires were obtained from 691 GPs (69%). Within the last 12 months 62.4% (n = 431) of the GPs had been consulted by at least one patient with MCS. Of these, 55.2% of the GPs evaluated the patients' complaints as chronic and 46.2% stated that they were rarely able to meet the patients' expectations for healthcare. The majority, 73.5%, had referred patients to other medical specialties. The cause of MCS was perceived as multi-factorial by 64.3% of the GPs, as somatic/biologic by 27.6%, and as psychological by 7.2%. Partial or complete avoidance of chemical exposures was recommended by 86.3%. Clinical guidelines, diagnostic tools, or more insight in the pathophysiology were requested by 84.5% of the GPs.

CONCLUSION

Despite the lack of formal diagnostic labelling the patient with MCS is well known by GPs. The majority of the GPs believed that MCS primarily has a multi-factorial explanation. However, perceptions of the course of the condition and management strategies differed, and many GPs found it difficult to meet the patients' expectations for healthcare. The majority of the GPs requested more knowledge and clinical guidelines for the management of this group of patients.

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.