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PubMedDate not supplied

Psychiatric illness in the first-degree relatives of persons reporting multiple chemical sensitivities.

The multiple chemical sensitivities (MCS) syndrome is characterized by unexplained physical and psychiatric complaints attributed by patients and some of their physicians to low-level chemical exposures. In this study, we interviewed 15 subjects with MCS and 21 controls about their first-degree relatives using the Family History-Research Diagnostic Criteria (FH-RDC). Subjects with MCS were more likely than controls to report their relatives to have major depression, alcoholism, panic disorder, obsessive-compulsive disorder, and antisocial personality disorder. They were also likely to have past suicide attempts, and to have received some form of psychiatric treatment (hospitalization, medication or electroconvulsive therapy, or counseling). Nearly 30% of the relatives of subjects with MCS were reported to have MCS themselves. Possible reasons for the findings are discussed.

Adult↗

PubMed1996

Medical management of the multiple chemical sensitivity patient.

Multiple chemical sensitivity (MCS) is a complex, chronic disorder characterized by multisystemic symptoms occurring in response to a wide variety of chemical odors or low-level exposures. The etiology is unknown but likely multifactorial. Patient evaluation includes a comprehensive history with a review of past medical records and a physical examination with specific attention to the affected organ systems. Laboratory evaluation is dependent on past testing and patient symptoms. It should be individualized and, although standard baseline tests are helpful, exhaustive testing is not. The evaluation is primarily designed to exclude diseases requiring specific medical therapy. Treatment approaches vary considerably depending on the treating physician and patient responsiveness; many have been adapted from those used for similar chronic illness of unknown etiology. Therapies utilized in MCS patients include supportive care, behavioral techniques, including desensitization, psychotherapy, chemical avoidance, and clinical ecology regimens such as provocation-neutralization protocols. The advantages and disadvantages of these approaches are discussed and the use of clinical ecology regimens is discouraged. A multidisciplinary approach similar to those used in chronic pain patients may be beneficial. Regardless of the treatment chosen, the goal should be to decrease patient disability.

Behavior Therapy↗

PubMed2004

Identification of responsible volatile chemicals that induce hypersensitive reactions to multiple chemical sensitivity patients.

Multiple chemical sensitivity (MCS) has become a serious problem as a result of airtight techniques in modern construction. The mechanism of the MCS, however, has not been clarified. Responsible chemicals and their exposure levels for patient's hypersensitive reactions need to be identified. We measured the exposure of 15 MCS patients to both carbonyl compounds and volatile organic compounds (VOCs) that may induce hypersensitive reactions. The exposures of those not suffering from MCS (non-MCS individuals) were also measured at the same time. To characterize the chemicals responsible for MCS symptoms, we applied a new sampling strategy for the measurement of carbonyls and VOCs using active and passive sampling methods. The results of our study clearly demonstrated that the chemicals responsible for such hypersensitive reactions varied from patient to patient. Moreover, the concentrations during hypersensitive symptoms, which were apparent in some of the MCS patients, were far below both the WHO and the Japanese indoor guidelines. The average exposure levels of MCS patients within a 7-day period were lower than those of paired non-MCS individuals except for a few patients who were exposed to chemicals in their work places. This result indicates that the MCS patients try to keep away from exposures to the chemical compounds that cause some symptoms.

Adolescent↗

PubMed1999

Acquisition and extinction of somatic symptoms in response to odours: a Pavlovian paradigm relevant to multiple chemical sensitivity.

OBJECTIVES: Multiple chemical sensitivity is a poorly understood syndrome in which various symptoms are triggered by chemically unrelated, but often odorous substances, at doses below those known to be harmful. This study focuses on the process of pavlovian acquisition and extinction of somatic symptoms triggered by odours. METHODS: Diluted ammonia and butyric acid were odorous conditioned stimuli (CS). The unconditioned stimulus (US) was 7.4% CO2 enriched air. One odour (CS+) was presented together with the US for 2 minutes (CS+ trial), and the other odour (CS-) was presented with air (CS-trial). Three CS+ and three CS-exposures were run in a semi-randomised order; this as the acquisition (conditioning) phase. To test the effect of the conditioning, each subject then had one CS+ only--that is, CS+ without CO2--and one CS- test exposure. Next, half the subjects (n = 32) received five additional CS+ only exposures (extinction group), while the other half received five exposures to breathing air (wait group). Finally, all subjects got one CS+ only test exposure to test the effect of the extinction. Ventilatory responses were measured during and somatic symptoms after each exposure. RESULTS: More symptoms were reported upon exposure to CS+ only than to CS-odours, regardless of the odour type. Altered respiratory rate was only found when ammonia was CS+. Five extinction trials were sufficient to reduce the level of acquired symptoms. CONCLUSION: Subjects can acquire somatic symptoms and altered respiratory behaviour in response to harmless, but odorous chemical substances, if these odours have been associated with a physiological challenge that originally had caused these symptoms. The conditioned symptoms can subsequently be reduced in an extinction procedure. The study further supports the plausibility of a pavlovian conditioning hypothesis to explain the pathogenesis of MCS.

Adult↗

PubMed1997

Provocative challenges in patients with multiple chemical sensitivity.

Whether multiple chemical sensitivity (MCS) is an organic disease initiated by environmental exposure or a psychologic disorder is a subject of controversy. The identification of pathophysiologic or psychophysiologic mechanisms occurring in patients with MCS after provocative challenges should be illuminating. Fifteen patients with MCS were challenged with their trigger substances and observed clinically. Prechallenge and postchallenge pulmonary function tests and PCO2, PO2, and oxygen saturation were measured. All of the patients whose symptoms were reproduced by the challenge (11 of 15) showed clinical evidence of acute hyperventilation with a rapid fall in PCO2 and no change or a rise in oxygen saturation. The symptoms and signs were consistent with an anxiety reaction with hyperventilation. Pulmonary function was unchanged; and recovery was rapid, aided in two cases by rebreathing into a paper bag. The most logical conclusion is that in these patients the MCS disorder is a manifestation of an anxiety syndrome triggered by their perception of an environmental insult, with at least some of their symptoms induced by hyperventilation.

Adult↗

PubMed2002

Anxiety sensitivity and depression in multiple chemical sensitivities and asthma.

Patients with sensitivities to multiple chemicals report symptoms of cognitive dysfunction, respiratory distress, and mood disturbance. Lifetime and current psychiatric disorders, personality traits associated with symptom reporting, and tests of cognitive function were compared between 30 subjects with Multiple Chemical Sensitivities (MCS), 19 asthmatics, and 31 healthy controls. Relative to asthmatics and controls, more MCS subjects met criteria for current depression and somatization disorder. MCS subjects and asthmatics scored significantly higher than controls on scales of chemical odor intolerance and anxiety sensitivity, both of which were significant predictors of physical symptoms. Few differences on objective neuropsychological tests were noted. However, MCS subjects with comorbid depression performed significantly worse on a verbal memory test relative to asthmatics but not to controls. Anxiety and depression are significant contributors to the physical and cognitive symptoms of MCS subjects.

Adult↗

PubMed2000

[Psychiatric and somatic morbidity of patients with suspected multiple chemical sensitivity syndrome (MCS)].

Multiple chemical sensitivity (MCS) or idiopathic environmental intolerance (IEI) is understood as an acquired disorder with multiple recurrent symptoms that cannot be traced to any well-known medical or psychiatric condition and is associated with diverse environmental influences that are well tolerated by the majority of people. In a prospective study, we investigated 120 consecutive patients admitted a university-based outpatient department for environmental medicine during 1 year. Apart from routine medical examination and special toxicological diagnostic procedures, a structured clinical interview for DSM-IV psychiatric disorders was performed with every patient. At least one psychiatric diagnosis was found in 100 patients. The diagnostic criteria for somatoform disorders were filled by 53 patients. We found lifetime or current affective disorders in 39 patients, anxiety disorders in 29, and substance dependency or abuse in 25. In 16 patients, personality disorders were diagnosed. Nine suffered from psychotic disorders. This is the largest prospective study with standardized psychiatric diagnostic methods concerning psychiatric morbidity and MCS. The data show that many patients with environmental health problems obviously suffer from somatoform disorders but also from other, well-known psychiatric conditions.

Adolescent↗

PubMed1995

[Multiple chemical sensitivity syndrome].

The multiple chemical sensitivity syndrome (MCS) is a novel constellation of symptoms in environmental medicine that has been extensively described and commented on in the USA. The main features of this syndrome are: multiple symptoms in different organ systems triggered by a variety of chemical substances, with relapses and exacerbations under certain precipitating circumstances at very low levels which do not cause any reactions in the population at large. There are no lab markers or specific investigative findings. This paper describes the historical development of the term MCS, its diagnostic criteria and pathophysiological aspects using 10 patient histories from our hospital.

Adult↗

PubMed2002

PET in patients with clear-cut multiple chemical sensitivity (MCS).

AIM: Multiple chemical sensitivity (MCS) is a controversially discussed symptom complex. Patients afflicted by MCS react to very low and generally non-toxic concentrations of environmental chemicals. It has been suggested that MCS leads to neurotoxic damage or neuroimmunological alteration in the brain detectable by position emission tomography (PET) and single photon emission computer tomography (SPECT). These methods are often applied to MCS patients for diagnosis, although they never proved appropriate. METHOD: We scanned 12 MCS patients with PET, hypothesizing that it would reveal abnormal findings. RESULTS: Mild glucose hypometabolism was present in one patient. In comparison with normal controls, the patient group showed no significant functional brain changes. CONCLUSION: This first systematic PET study in MCS patients revealed no hint of neurotoxic or neuroimmunological brain changes of functional significance.

Adult↗

PubMed1996

Neurobehavioral performance in multiple chemical sensitivities.

Individuals with Multiple Chemical Sensitivities (MCS) frequently report difficulties in attention/concentration, memory and accuracy and speed of problem solving. We evaluated neurobehavioral functioning in 35 chemically exposed patients referred to our Occupational and Environmental Neurology Clinic. Of these 35 patients, 17 presented with symptoms of MCS and 16 patients reported no symptoms of MCS. In addition, we used a group of 126 healthy controls for comparison. The performance of the MCS group was not significantly different from that of the control group on tests of verbal learning and memory, executive functioning, and psychomotor functioning. The MCS group performed below the control group on a test of visual learning and memory, but this performance was similar to the group with chemical exposure and no MCS. Therefore, performance on objective neurobehavioral tests did not confirm the most frequently reported subjective complaints of patients with MCS. These results suggests that patients with symptoms of MCS do not have compromised central nervous system functioning.

Adult↗

PubMed2001

Anxiety and depressive states in multiple chemical sensitivity.

Cases with multiple chemical sensitivity (MCS) frequently present mental symptoms. This study discusses the characteristics of the anxiety and depressive state of MCS by comparing patients of MCS with a gender and age-matched control group. In this investigation, MCS cases were selected among those satisfying the diagnostic criteria of Cullen after ruling out other physical diseases. Patients visiting ophthalmologists with other diseases were designated as the control. Evaluation of the anxiety and depressive state was performed in 48 cases of MCS and 48 controls using the Japanese version of the State-Trait Anxiety Inventory, the Self-rating Depression Scale (SDS), and the Hamilton Rating Scale for Depression. Significantly higher mean values of subjective anxiety and a depressive state were obtained in 18 MCS cases than in 18 controls for the follow-up patients, while no significant difference was observed between MCS and controls of 30 new patients for each group. Therefore, anxiety in MCS is characterized by the continuous high anxiety level. MCS is also characterized by a continuance of depressive state at a "neurotic level" category by SDS. The anxiety scores and depressive levels were highly correlated in MCS and controls at the first and subsequent appearances, except those in the follow-up control cases. In conclusion, both anxiety and a depressive state in MCS remained at high level until the subsequent examination, when those in controls decreased to a normal level.

Adult↗

PubMed1999

Multiple chemical sensitivity: potential role for neural sensitization.

An emerging issue in environmental health is the phenomenon of multiple chemical sensitivity (MCS). Multiple chemical sensitivity is a controversial disorder characterized by multiorgan symptoms in response to low-level chemical exposures that are considered safe for the general population. The onset of MCS is often attributed to prior repeated chemical exposures in the home and/or workplace, and, once initiated, symptoms are triggered by extremely low levels of many chemicals/foods. No single case definition exists for MCS due to several issues that call into question its validity as a distinct illness induced by prior chemical exposure. Hypotheses regarding the etiological basis for MCS range from direct toxicological effects of chemicals to the notion that MCS is purely a psychological "belief system". One leading hypothesis suggests that MCS represents a neural sensitization phenomenon, wherein susceptible individuals demonstrate extreme sensitivity to chemicals and odor intolerance due to central nervous system (CNS) sensitization processes. The recent development of an animal model for MCS provides some support for the sensitization hypothesis and may offer evidence for behavioral changes observed in at least a subset of those reporting MCS.

Animals↗

PubMed2002

Sensitization as a mechanism for multiple chemical sensitivity: relationship to evolutionary theory.

Multiple chemical sensitivity (MCS) is a disorder in humans attributed to prior chemical exposure. Sensitization is an amplification of neuronal responsiveness that elicits increased behavioral responding to stimuli, and occurs in a recently developed rat model of MCS. Rats were exposed to repeated formaldehyde (Form) and their response in three behavioral tests, including locomotor activity after a cocaine challenge, conditioned fear, and behavioral avoidance of Form, was assessed. In all three tests, rats demonstrated sensitized behaviors, implicating amplified responding within specific limbic brain regions. Evolutionary theory in the context of MCS specifies how the behavioral strategies of those with MCS are consistent with the notion that their self-perceived sense of survival and reproductive fitness may be threatened by chemical exposures. This behavior may be mediated by the same limbic brain regions that become sensitized after repeated chemical exposure in animals.

Animals↗

PubMedDate not supplied

Neural sensitization model for multiple chemical sensitivity: overview of theory and empirical evidence.

This paper summarizes theory and evidence for a neural sensitization model of hyperresponsivity to low-level chemical exposures in multiple chemical sensitivity (MCS). MCS is a chronic polysymptomatic condition in which patients report illness from low levels of many different, structurally unrelated environmental chemicals (chemical intolerance, CI). Neural sensitization is the progressive host amplification of a response over time from repeated, intermittent exposures to a stimulus. Drugs, chemicals, endogenous mediators, and exogenous stressors can all initiate sensitization and can exhibit cross-sensitization between different classes of stimuli. The properties of sensitization overlap much of the clinical phenomenology of MCS. Animal studies have demonstrated sensitization to toluene, formaldehyde, and certain pesticides, as well as cross-sensitization, e.g., formaldehyde and cocaine. Controlled human studies in persons with self-reported CI have shown heightened sensitizability in the laboratory to nonspecific experimental factors and to specific chemical exposures. Useful outcome measures include spectral electroencephalography, blood pressure, heart rate, and plasma beta-endorphin. Findings implicate, in part, dopaminergic mesolimbic pathways and limbic structures. A convergence of evidence suggests that persons with MCS or with low-level CI may share some characteristics with individuals genetically vulnerable to substance abuse: (a) elevated family histories of alcohol or drug problems; (b) heightened capacity for sensitization of autonomic variables in the laboratory; (c) increased amounts of electroencephalographic alpha activity at rest and under challenge conditions over time. Sensitization is compatible with other models for MCS as well. The neural sensitization model provides a direction for further systematic human and animal research on the physiological bases of MCS and CI.

Autonomic Nervous System↗

PubMed2004

[Validation of a screening instrument for multiple chemical sensitivity (MCS): the chemical odor sensitivity scale (COSS)].

Multiple Chemical Sensitivity (MCS) -- also known as Idiopathic Environmental Intolerances (IEI) -- is defined as a disorder with multiple somatic and psychological symptoms attributed to low levels of various, chemically unrelated substances in the environment. Self-reported chemical odor sensitivity is an important feature of MCS. We describe the construction and the reliability and validity properties of a short questionnaire for the assessment of chemical odor sensitivity (COSS). The 11 items of the COSS were factor analytically derived from the Questionnaire of Chemical and General Environmental Sensitivity (CGES). Test statistical properties of the COSS were examined in college students, unselected community members, environmental medicine outpatients and chemically sensitive subjects. The COSS achieved good internal consistency in all samples (Cronbach's alpha = 0.89 - 0.93). Women and subjects from samples with higher MCS risk showed elevated COSS scores. The scale showed adequate construct validity and proved useful as an economic screening instrument for persons at risk for MCS.

Adult↗

PubMed1996

Multiple chemical sensitivity multiorgan dysesthesia, multiple symptom complex, and multiple confusion: problems in diagnosing the patient presenting with unexplained multisystemic symptoms.

Patients are presenting in increasing numbers with multiorgan symptoms allegedly resulting from exposure to environmental chemicals. Among the symptoms expressed by patients with alleged multiple chemical sensitivities (MCS) are profound fatigue, mental confusion, myalgia, depression, anxiety, dizziness, headache, insomnia, loss of appetite, and numbness of the extremities, all in the absence of objective physical signs. Diagnostic criteria to assess the effects of environmental agents on organ systems are sorely needed because patients with MCS often have no tissue pathology or physiological abnormalities, but often do have diagnosable psychiatric illnesses. In treating patients with MCS, the physician should first perform a complete history and physical examination, including a comprehensive evaluation of chemical exposure. If the findings strongly suggest the presence of disease related to particular organ systems, further diagnostic evaluation should be undertaken. If abnormal findings are absent, psychiatric advice may be useful. The physician should keep an open mind about MCS but must also remember that a cause-effect relationship between exposure to multiple chemicals and symptoms has not been established.

Air Pollutants↗

PubMed1998

[Multiple chemical sensitivity: theories of etiopathogenesis].

Multiple chemical sensitivity (MCS) is a controversial disorder of uncertain etiology, characterized by recurrent symptoms referable to multiple organ systems, occurring as a response to chemically unrelated compounds at doses far below those established to cause harmful effects in the general population. The fundamental question is whether the MCS is primarily a toxicodynamic phenomenon (a pathological interaction between a chemical agent and organ systems, possibly acting through a mechanism different from those known in toxicology) or a psychogenic disorder (an emotional reaction to perceived toxic agents). This paper presents some recent theories of etiopathogenesis of the MCS discussing the role of immunological, inflammatory, metabolic, psychophysiologic, and neurochemical mechanisms, as well as the role of neural sensitization in the etiology of the disorder. The paper foregrounds the complex relation between psychiatric disorders and social factors, on one hand, and the MCS on the other. A particular emphasis is put on the relevance of the MCS research for clinical practice, public health, and regulatory decisions.

Humans↗

PubMed1996

Multiple chemical sensitivities syndrome: a review.

Multiple chemical sensitivities (MCS) syndrome is a controversial diagnosis that has arisen in the latter half of the 20th century. Clinical ecologists strongly believe that multiple common environmental chemicals assault the immune system in certain individuals, producing multisystem disease. Mainstream medicine, however, largely believes that the symptoms of MCS syndrome can be attributed to a conditioned response to the environment and psychiatric disease. This review examines the controversy surrounding MCS syndrome in regard to the etiology, diagnosis, and management.

Environmental Exposure↗