This may be old news to some, but it bears repeating.
1.J Allergy Clin Immunol. 2000 Feb;105(2 Pt 1):358-63.
Carbon dioxide inhalation challenges in idiopathic environmental intolerance.Poonai N, Antony MM, Binkley KE, Stenn P, Swinson RP, Corey P, Silverman FS, Tarlo SM.
New York (MedscapeWire) Feb 18 — A study by Canadian researchers in the February issue of the Journal of Allergy and Clinical Immunology suggests that patients with idiopathic environmental intolerance (IEI, formerly known as multiple chemical sensitivity) display high anxiety sensitivity similar to patients with panic disorder (PD) under controlled conditions.
Previous studies have been unable to prove any underlying allergic or toxic basis to IEI. Other research has found that IEI has increased psychiatric morbidity and shares many features with PD which involve the onset of sudden anxiety. Symptoms shared include chest tightness, breathlessness, palpitations, apprehension, and avoidance of situations where symptoms occur.
In this blinded study, patients inhaled differing concentration of oxygen and CO2 through a flow spirometer. After each inhalation, patients were asked to rate each panic symptom and their sensations of panic and fear on an objective Diagnostic Symptom Questionnaire.
When inhaling increasing concentrations of CO2, a large percentage (48%-92%) of patients with PD frequently experienced panic symptoms, whereas only 5% of healthy subjects noted similar symptoms. Researchers found that 71% of IEI patients fulfilled similar PD criteria after inhaling CO2. There were no significant differences between IEI and control groups in terms of actual breathing rate, heart rate, and other physical measures.
Investigators concluded that the high rate of anxiety response to inhaled CO2 among IEI patients shows a tendency to overreport and possibly catastrophically misinterpret benign physical symptoms, a consistent finding among patients with PD. The authors suggest a psychological assessment should be considered in all patients with IEI.
2. J Allergy Clin Immunol. 2006 Dec;118(6):1257-64. Epub 2006 Sep 25.
Multiple chemical sensitivities: A systematic review of provocation studies.Das-Munshi J, Rubin GJ, Wessely S.
Section of Epidemiology, Institute of Psychiatry, London
A systematic review of provocation studies of persons reporting multiple chemical sensitivities (MCS) was conducted from databases searched from inception to May 2006. Thirty-seven studies were identified, testing 784 persons reporting MCS, 547 control subjects, and 180 individuals of whom a subset were chemically sensitive. Blinding was inadequate in most studies. In 21 studies odors of chemicals were probably apparent; 19 of these reported positive responses to provocations among chemically sensitive individuals, and 1 study demonstrated that negative expectations were significantly associated with increased symptom reporting after provocations. Seven studies used chemicals at or below odor thresholds, and 6 failed to show consistent responses among sensitive individuals after active provocation. Six studies used forced-choice discrimination and demonstrated that chemically sensitive individuals were not better at detecting odor thresholds than nonsensitive participants. Three studies tested individuals by using nose clips/face masks and confirmed response, possibly mediated through eye exposure. Three studies used olfactory masking agents to conceal stimuli, and none of these found associations between provocations and response. We conclude that persons with MCS do react to chemical challenges; however, these responses occur when they can discern differences between active and sham substances, suggesting that the mechanism of action is not specific to the chemical itself and might be related to expectations and prior beliefs.
PMID: 17137865 [PubMed – indexed for MEDLINE]
3. Clin Neuropsychol. 2006 Dec;20(4):848-57.
MMPI-2 profiles of persons with multiple chemical sensitivity.Binder LM, Storzbach D, Salinsky MC.
Oregon Health and Sciences University, Beaverton, OR, USA.
We compared the MMPI-2 profiles of adults with multiple chemical sensitivity (MCS), epileptic seizures (ES), and nonepileptic seizures (NES). Both NES and MCS are medically unexplained conditions. In previous studies profiles associated with NES were elevated on scales Hs and Hy, compared with profiles associated with ES. We predicted that profiles associated with MCS would be elevated on Hs and Hy compared with the ES group. Patients with ES and NES were diagnosed after intensive EEG monitoring using published criteria. MCS was diagnosed if there was a complaint of illness in response to multiple common odors at levels that are not noxious to most people. All the MCS cases had legal claims for injury related to chemical exposures. The results showed that on MMPI-2 scales Hs, D, and Hy the MCS group had means significantly higher than both the ES and NES groups. Fake Bad Scale scores were elevated in 11 MCS cases, and regression-based estimates of Fake Bad Scale scores showed elevation in the MCS group compared with both seizure groups. We conclude that MMPI-2 data, obtained from people seeking financial compensation, indicate that there is a strong psychological component to MCS symptoms.
PMID: 16980266 [PubMed – indexed for MEDLINE]
4.Ugeskr Laeger. 2006 Mar 13;168(11):1116-9.[Multiple chemical sensitivity, a well-defined illness?]
Kolstad HA, Silberschmidt M, Nielsen JB, Osterberg K, Andersen JH, Bonde JP, Fink P.
Arhus Universitetshospital, Arbejdsmedicinsk Klinik, Arhus C.
Some people react to smells or chemicals at levels far below toxicological thresholds with nonspecific symptoms, fear and social isolation. They may be diagnosed with multiple chemical sensitivity. There is no empirical evidence indicating that this condition is explained by toxicological mechanisms, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained in appropriate confrontation with the chemicals encountered in everyday life.
PMID: 16545215 [PubMed – indexed for MEDLINE]
5. J Occup Environ Med. 2006 Jan;48(1):76-82.
New aspects of psychiatric morbidity in idiopathic environmental intolerances.
Hausteiner C, Mergeay A, Bornschein S, Zilker T, Förstl H.
Department of Psychiatry and Psychotherapy, Technical University Munich, Munich, Germany
OBJECTIVE: To understand idiopathic environmental intolerances (IEI)-formerly multiple chemical sensitivities (MCS)-it is helpful to outline its characteristic psychiatric morbidity. METHOD: We applied a standardized interview according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (SCID) to 305 environmental patients with and without IEI. RESULTS: Somatoform, affective and anxiety disorders were the most frequent diagnoses but only slightly differed between patients with or without IEI. In both groups, current substance-related disorders were rare. We found a clearly higher prevalence of psychotic, especially current delusional disorders, in IEI. CONCLUSION: Somatization, depression, and anxiety are frequent in IEI but nonspecific. Psychotic disorders are more common in IEI than in other types of environmental illness. It appears worthwhile to study personality and cognitive style to explain the pivotal features of IEI.
PMID: 16404213 [PubMed – indexed for MEDLINE]
6. Responses to panic induction procedures in subjects with multiple chemical sensitivity/idiopathic environmental intolerance: understanding the relationship with panic disorder.Tarlo SM, Poonai N, Binkley K, Antony MM, Swinson RP.
Gage Occupational and Environmental Health Unit, University of Toronto, Toronto, Ontario, Canada.
Idiopathic environmental intolerance (IEI), also known as multiple chemical sensitivity, is a clinical description for a cluster of symptoms of unknown etiology that have been attributed by patients to multiple environmental exposures when other medical explanations have been excluded. Because allergy has not been clearly demonstrated and current toxicological paradigms for exposure-symptom relationships do not readily accommodate IEI, psychogenic theories have been the focus of a number of investigations. A significantly higher lifetime prevalence of major depression, mood disorders, anxiety disorders, and somatization disorder has been reported among patients with environmental illness compared with that in controls. Symptoms often include anxiety, lightheadedness, impaired mentation, poor coordination, breathlessness (without wheezing), tremor, and abdominal discomfort. Responses to intravenous sodium lactate challenge or single-breath inhalation of 35% carbon dioxide versus a similar breath inhalation of clean air have shown a greater frequency of panic responses in subjects with IEI than in control subjects, although such responses did not occur in all subjects. Preliminary genetic findings suggest an increased frequency of a common genotype with panic disorder patients. The panic responses in a significant proportion of IEI patients opens a therapeutic window of opportunity. Patients in whom panic responses may at least be a contributing factor to their symptoms might be responsive to intervention with psychotherapy to enable their desensitization or deconditioning of responses to odors and other triggers, and/or may be helped by anxiolytic medications, relaxation training, and counseling for stress management.
PMID: 12194904 [PubMed – indexed for MEDLINE]