New aspects of psychiatric morbidity in idiopathic environmental intolerances

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.

Symptoms of Idiopathic Environmental Intolerance associated with chemicals (IEI-C) are positively associated with perceptual anomalies

OBJECTIVE

Idiopathic Environmental Intolerance (IEI; i.e. the experience of somatic symptoms attributed to environmental agents) represents a functional somatic syndrome of unclear aetiology. Based on previous findings that suggest an association between IEI and perceptual anomalies, this study aimed to investigate the relationship between symptoms of IEI associated with chemicals (IEI-C) and facets of the schizotypy spectrum.

METHODS

A cross-sectional study design was used with N = 410 (78.3% female) persons responding to an online survey in which chemical odor sensitivity (COS) and modern health worries (MHW) that are associated with IEI-C, as well as schizotypal personality traits (SPQ), hallucination proneness (LSHS) and delusional ideation (PDI) as core components of the schizotypy spectrum were assessed.

RESULTS

Schizotypal traits were found to be significantly positively associated with MHWs (r = 0.20, p = .01), COS (r = 0.23, p = .01), and showed significant positive associations with hallucination proneness. Magical thinking was found to exhibit a significant positive relationship with both MHW (r = 0.17, p = .01) and COS (r = 0.21, p = .01). These small associations between IEI-C and facets of the psychosis spectrum remained significant even after statistically controlling for individual levels of trait anxiety and depression.

CONCLUSION

Schizotypal personality traits, particularly magical thinking, and hallucination proneness, appear positively related to facets of IEI-C. The findings are of relevance for the advancement of theoretical models of IEI.

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.

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.

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.

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.

The correlation between mental health and multiple chemical sensitivity: a survey study in Japanese workers

OBJECTIVE

This study was designed to determine the correlation between mental health and multiple chemical sensitivity (MCS).

METHOD

The present study was conducted at two companies in 2011; both in Kyushu, Japan. The "subjective symptoms" subscale of the "Self-diagnosis Checklist for Assessment of Workers' Accumulated Fatigue" was used as a mental health subscale. To determine if multiple chemical exposure has an impact on mental health, we composed an original path model using structural equation analysis.

RESULT

Our final path model can be regarded as good: CMIN/DF = 1.832, CFI = 0.996, and RMSEA = 0.038, AIC = 71.158. As expected, chemical sensitivity and other chemical sensitivity scores predicted the health effects of multiple chemical exposure (β = 0.19, 0.64). Mental health was predicted by symptom severity and life impact (β = 0.56 and 0.12), which were both affected by multiple chemical exposure (β = 0.38 and 0.89, respectively).

CONCLUSION

As far as we are aware, this is the first study using path analysis to explore whether MCS can indicate mental health in worker populations worldwide, and we found a significant causal relationship between them. This could indicate that more focus should be placed on the impact of MCS on mental health in future investigations.

Metric properties and normative data for brief noise and electromagnetic field sensitivity scales

Aims: Lack of brief questionnaire instruments for quantifying affective reactions to and behavioral disruptions attributed to sounds and electromagnetic fields (EMFs) motivated the present development and metric evaluation of such instruments, called the 11-item Noise Sensitivity Scale (NSS-11) and the 11-item Electromagnetic Field Sensitivity Scale (EMFSS-11). Another objective was to establish normative data for these instruments. Method: Data from 3406 individuals who took part in the Västerbotten Environmental Health Study was used. The participants constitute a random sample of inhabitants in the county of Västerbotten in Sweden, aged 18 to 79 years, stratified for age and gender. The participants responded to the NSS-11 and EMFSS-11 and to additional questions for evaluation of concurrent validity. Results: The results show satisfying reliability (Cronbach α = 0.71–0.85, varying with age group and gender), concurrent validity, and unidimensionality of the NSS-11 and EMFSS-11, and that the scales generate scores with approximately normal distributions, irrespective of age group and gender. Mean scores, standard deviations, and confidence intervals constitute normative data. Conclusions: The favorable metric properties of the NSS-11 and EMFSS-11 in combination with their fast usage suggest that they are particularly useful for assessment in epidemiological studies, and have the advantage of available normative data.

Magical thinking in somatoform disorders: an exploratory study among patients with suspected allergies

BACKGROUND

In order to reconceptualize somatoform disorders (SFDs), the psychological characteristics of SFD patients are increasingly investigated. The cognitive style of magical thinking (MT) has not been studied so far in patients with SFDs.

SAMPLING AND METHODS

In a cross-sectional study, 201 allergy workup patients were interviewed using the Structured Clinical Interview for DSM-IV; they answered a set of self-report questionnaires including the Schizotypal Personality Questionnaire subscale for MT and the Patient Health Questionnaire (PHQ). The expression of MT was explored in 61 patients with SFDs compared to 140 patients without SFDs.

RESULTS

Patients with SFDs reached higher scores of MT, also when controlled for gender, depression, and anxiety. In particular, they stated more frequently that they were believers in telepathy (64 vs. 44%) and clairvoyance (43 vs. 16%). MT correlated only weakly with somatization/somatic symptom severity, depression, and anxiety.

CONCLUSIONS

Among allergy workup patients with SFDs we found considerable MT. This indicates that SFD patients may tend to mistake correlation for causality in a more general way, and not just in an illness-related context. The relation to indicators of illness severity (somatic symptom severity/somatization, depression, and anxiety) was relatively weak. Possible implications for research, diagnostics, and therapy are discussed.

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.

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".

Pest controllers: a high-risk group for Multiple Chemical Sensitivity (MCS)?

INTRODUCTION

Based on the assumption that professional groups with frequent chemical exposure are at an increased risk for developing Multiple Chemical Sensitivity (MCS), a sample of 45 professional pest controllers was investigated.

METHODS

The examination of the pest controllers consisted of a physical and laboratory examination with urine screening for pyrethroid metabolites, a psychiatric interview, a neuropsychological test battery, and a chemical sensitivity questionnaire.

RESULTS

Persistent or serious work related health problems and chemical sensitivity were not reported. In urine, cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br(2)CA) was detected in 11%, 4-fluoro-3-phenoxybenzoic acid (F-PBA) in 7%. 3-phenoxybenzoic acid (3-PBA) exceeded the reference range in 9%, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid (Cl(2)CA) in 20%. Increased liver enzymes and blood count deviations were rather common. 38% had psychiatric disorders. With few exceptions, neuropsychological testing results were normal.

CONCLUSIONS

The results do not support the hypothesis that work-related insecticide exposure promotes chemical sensitivity.

The impact of work environment on mood disorders and suicide: Evidence and implications

The purpose of this paper is to review the evidence estimating an impact of occupational factors on mood disorders and suicide, and the efficacy of interventions. This review is based on literature searches using Medline and Psych INFO from 1966 to 2007 (keywords: work stress, job insecurity, job strain, shift work, violence, occupational health, mood disorders, depression, and suicide). To establish the relationship between occupational variables and mood disorders, we focused on clinically significant disorders rather than depressive symptoms. During the last decade, prospective epidemiological studies have suggested a predictive association between the work environment and mood disorders. Recently, increasing numbers of clinical trials have shown favorable effect size of intervention and suggested preferable return-on-investment results. However, low awareness and social stigma still decrease workers access to treatment. Mental health professionals in conjunction with employers have to devise a creative system to make the quality care being offered more accessible to employees. In addition, further outcome data is needed to evaluate the benefit of managing mood disorders in the workplace, and to foster awareness of positive implications for employees, employers, their families, and the society at large. In addition, the work environment, with its chemical (e.g. chemosensory factors, pollutants), physical (e.g. lighting, noise, temperature, outdoor views and activities), biological (e.g., chronobiological factors, allergens, infectious agents), psychological (e.g. demand-control, effort-reward balance), social (e.g. cohesiveness, support), and organizational (e.g. leadership styles) component should meet minimal standards, and may improve with striving towards the optimum.

Multiple chemical sensitivities: review

PURPOSE OF REVIEW

There have been a number of recent studies examining behavioural and social factors in the potential cause of Multiple Chemical Sensitivities, or Idiopathic Environmental Intolerance. The current review will draw together recent research and suggest directions for future investigation.

RECENT FINDINGS

Recent studies have implicated a number of different perspectives which may be helpful in understanding the cause of chemical sensitivities. A multifactorial model incorporating behavioural, physiological and sociological approaches may be useful. Cultural and historical factors, alongside individual expectations and beliefs, as well as maladaptive learning and conditioning processes, may be important in the specific cause of chemical sensitivities. Iatrogenesis, through the promise of unproven 'therapies', may perpetuate reported symptoms further. Although there are many recent experiments implicating potential behavioural or psychological causes for Multiple Chemical Sensitivities, there remains a paucity of treatment trials for this condition.

SUMMARY

Good-quality treatment trials examining psychological/behavioural approaches in the management of Multiple Chemical Sensitivities are urgently needed.

Psychologische Korrelate des Multiple Chemical Sensitivity (MCS)

Zusammenfassung. Theoretischer Hintergrund: Multiple Chemische Sensitivität (MCS) ist ein Syndrom mit organisch unerklärbaren Beschwerden, die von den Betroffenen auf niedrig dosierte Umweltschadstoffe attribuiert werden. Eine Risikogruppe für MCS stellen Probanden (Pbn) mit selbstberichteter Chemischer Sensitivität (CS) dar. Fragestellung: Sind eher toxikogene oder eher psychogene Faktoren für den Bericht von MCS-Beschwerden entscheidend? Methode: Fragebogenuntersuchung an 309 Studierenden, die sich in einem mit Polychlorierten Biphenylen (PCB) belasteten Universitätsgebäude aufhielten; Querschnittstudie. Ergebnisse: Während Expositionsdauer und MCS-Syndrom nicht korrelierten, lieferten psychologische Variablen (umweltbezogene Gefährdungskognitionen, Krankheitsangst, habituelle Sorgen und Absorption) hingegen einen signifikanten Beitrag zur Vorhersage des MCS-Syndroms. Nur Pbn mit CS, aber nicht jene ohne CS, berichteten nach Aktivierung eines “Schadstoffbelastungs-Schemas“ vermehrt MCS-Beschwerden. Schlussfolgerungen: Nach den Ergebnissen dieser Querschnittsuntersuchung und anderer Studien scheinen kognitive und andere psychologische Faktoren eine bedeutsame Rolle bei der Entstehung und Aufrechtung dieses Syndroms zu spielen.

Dysfunctional cognitions in idiopathic environmental intolerances (IEI)—An integrative psychiatric perspective

Idiopathic environmental intolerances (IEI) - formerly multiple chemical sensitivities (MCS) - are characterized by diffuse symptoms reported after exposure to low doses of everyday chemicals. Previous theories about the origin of IEI have emphasized either biological or psychological factors, neglecting a probable interplay. Many have suggested classifying IEI as a somatoform or an anxiety disorder, irrespective of some incongruities. By focusing on dysfunctional cognitions we discuss obvious parallels of IEI with somatoform disorders, and also indicate overlaps with anxiety and delusional disorders. To propose a hypothetical psycho-neurobiological basis of IEI, recent evidence about cortically represented symptoms in the absence of peripheral stimuli is briefly summarized. We conclude that IEI can serve as an illustrative example for the impact of cognitive, representational processes in symptom generation.

The concept of neurosis in a cross-cultural perspective

PURPOSE OF REVIEW

The aim of this review is to discuss the current state of research on the concept of neurosis across cultures and to document the advances made in this field over the previous year.

RECENT FINDINGS

There has been a significant alteration in the concept of neurosis in most cultures, with the relative abandonment of the term 'neurosis' and replacing the concept with that of common mental disorders. The state of research on the aetiopathogenesis of neurosis has moved towards neurobiological, neurophysiological and genetic factors. Neuroticism as a personality trait has retained its role in the development of neurotic disorders. The epidemiological studies on neurotic disorders are equivocal across cultures. Besides, studies on clinical presentation of common mental disorders, somatization and abnormal illness behaviour show some cultural variations. Though there are no significant advances in the management of neurosis equivalents, it seems that the specific serotonin receptor inhibitors may have a role in management of these conditions.

SUMMARY

The recent literature shows acceptance of common mental disorders across cultures replacing neurotic disorders. Other conceptual equivalents of neurosis are seen in somatoform disorders, somatization and abnormal illness behaviour. Some traditional culture-bound neurotic syndromes and idioms of distress persist.