Multiple Chemical Sensitivities Addendum to Biologic Markers in Immunotoxicology (1992) / Chapter Skim
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Neuropsychiatric and Biopsychosocial Mechanisms in Multiple Chemical Sensitivity: An Olfactory-Limbic System Model
Neuropsychiatric and Biopsychosocial Mechanisms in Multiple Chemical Sensitivity: An Olfactory-Limbic System Model
Pages 89-108
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From page 89... ...
This model means Hat MCS would mvolve a continuum and interaction of mechanisms In term of the relative contributions of biological, psychological, "d social factors in a given patient. Genedcally-based neurochemical and/or receptor v~erabilities ~ the central and autonomic nervous systems would malce certain subsets of the population more likely to experience adverse effects of low dose chemical exposures.
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From page 90... ...
Patients with MCS report multiple symptoms In multiple systems. Clinical observations also include initial sensi~ion USA acute high dose exposure, chrome low-cost sensitivity, Spreading of number of sensitivities from one to many chemicals, adaptation to chrome exposures, and concomitant multiple food sensitivities (MFS)
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From page 91... ...
This study presented Me chemicals in ~ environmentally controlled ~ chamber, but did not mark the ideate of Me chemical exposures or Copulate possible adaptation to the test items. Thus, these data confirm Me presence of autonomic differences ~ MCS patients in terms of respiration and nasal airway fi=ction to Pacific chemical challenges, but do not address the larger clinical syndrome under consideration.
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From page 92... ...
Moreover, nose of Me studies that found increased depression, ~eW, andJor somatoform disorder histories compared MCS patients with chronically-ill control groups as opposed to healthy normals. Since chronic illnesses of all types, including cancer, heart disease, "d auto~mmune disorder have a current or past prevalence of depression and anthem disorders ranging from 5% to as high as 4555 (general average, 20%)
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From page 93... ...
That is, the mechanisms of depression and Wear, as well as over psychiatric symptoms, involve putative dysregulation of bram chemistry and neurobansmitter receptors ~ specific neural pathways (Reiman et al., 1986; Talbott et al., 1988~. Thus, one might expect individuals vulnerable to major psychiatric disorders be Long the most s~ptible to low doses of those environmental chemicals that could worm Weir inherent dysfimctions ~ bow chemistry, either by direct action or by activation of endogenous mediators (}sell, 19821.
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From page 94... ...
Olfactory Bulbecto~ Model of Depression It is also striking ~ one of the best animal models of depression currently used by drug compares to identify new antidepr~t medications is that of olfactory bulbectomy (Jesberger and Richardson, 1988; van Riezen and Leonard, 1990~. As in human depression, animus with olfactory bulb dodge demonsmam neuroanatomic dysregulation of the limbic-hypothalamc ems, neurochemical imbalances of serotonin, norepinephrine, g~mma-atnino-buqric acid, and aceWlcholine, and improvement from chronic but not acute treatment with antidepressant drugs (Jesberger and Richardson, 1988~.
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From page 95... ...
Furthermore, Bokina reported alterations in visual evoked potentials dig chronic exposure to low concentrations of formaldehyde and ozone. Id summary, olfactory pathway kindling and LTP might par~cipam in regstenog information conceding past high dose and/or cumulative low dose chemical exposures Cat would increase the likelihood of limbic responsivity to subsequent low dose exposures.
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From page 97... ...
James et al., 1987~. TO factors in term of sequencing high to low dose exposures and of giving repeated low dose exposures may be necessary to elicit the proposed phenomena.
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From page 98... ...
. The mediating mechanisms of these types of effects may involve hormonal, central nervous, and autonomic nervous system elements.
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From page 99... ...
METHODOLOGICAL ISSUES Methodological issues In He study of MCS are critically important. While He scope of this paper is limited to multiple chemical sensitivities, the body of controlled literate on multiple food sensitivities offers valuable clues to the proper design of studies on chemicals and chemically-sensitive patients (Pearson et al., 1983; Egger et al., 1985; Kahn et al., 1988, 1989; Kaplan et al., 1989~.
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From page 100... ...
Patients who are in fact chemically sensitive to various substances may nonetheless hold incorrect beliefs about their reactivity to any Specific chemical Ol1 a single day for a wide range of reasons, including the reality that no chemical exposure in real life is expenenced separate from thousands of others in ambient air. Thus, Molhave's approach of sing investigation of tight building subjects and nonnals u ith Matures of volatile organic compounds similar to those found im indoor air may be the most appropriate Cot step In MCS research as well (Molhave et al., 1986; Molhave 1990; Otto et al., 1990)
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From page 101... ...
Overall, as is common ~ the clinical practice of biopsychosocial patient care, the first priority should be to study the direct biological effects of low dose chemical exposures on health in the subset of individuals vulnerable to multiple chemical ~tivitr. The next prion~ is to exams e interactions between Me biological Id psychosocial dimensions of MCS.
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From page 102... ...
1974. The role of the olfactory bulb ~ limbic mechanisms.
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From page 103... ...
Shapiro 1988. Olfactory sensitivity, nasal resistance, and autonomc fimction ~ patients with multiple chemical sensitivities.
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From page 104... ...
BE output dysregulation induced by olfactory bulbectomy: an approximation in the rat of major depressive disorder in humans. latex.
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From page 105... ...
Hunger reactions to low concentrations of volatile organic compounds. Environment International 12:167-175.
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From page 106... ...
The application of positron emission tomography to the study of panic disorder.
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From page 107... ...
Washington, D.C.: American Psychiatric Press, ldc.
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From page 108... ...
Effects of psychotropic drugs on the behavior and neurochemistry of olfactory bulbectomi~d rats.
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