MCS – American ME and CFS Society

Comparison of patients with chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS), fibromyalgia (FM), and multiple chemical sensitivities (MCS) are conditions associated with fatigue and a variety of other symptoms that appear to share many clinical and demographic features. Our objectives were to describe the similarities and differences among patients with CFS, FM, and MCS. Additional objectives were to determine how frequently patients with MCS and FM met the criteria for CFS and if they differed in their health locus of control.

METHODS: Demographic, clinical, and psychosocial measures were prospectively collected in 90 patients, 30 each with CFS, FM, and MCS. Patients were recruited from a university-based referral clinic devoted to the evaluation and treatment of chronic fatigue and three private practices. Variables included demographic features, symptoms characteristic of each condition, psychological complaints, a measure of health locus of control, and information on health care use.

RESULTS: Overall, the three patient groups were remarkably similar in demographic characteristics and the presence of specific symptoms. Patients with CFS and FM frequently reported symptoms compatible with MCS. Likewise, 70% of patients with FM and 30% of those with MCS met the criteria for CFS. Health care use was substantial among patients with CFS, FM, and MCS, with an average of 22.1, 39.7, and 23.3 visits, respectively, to a medical provider during the prior year. Health locus of control did not differ among the three populations.

CONCLUSIONS: In general, demographic and clinical factors and health locus of control do not clearly distinguish patients with CFS, FM, and MCS. Symptoms typical of each disorder are prevalent in the other two conditions.

Comment in: Chronic fatigue, fibromyalgia, and chemical sensitivity: overlapping disorders. [Arch Intern Med. 1995]

Source: Buchwald D, Garrity D. Comparison of patients with chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities. Arch Intern Med. 1994 Sep 26;154(18):2049-53. http://www.ncbi.nlm.nih.gov/pubmed/8092909

Neuropsychology and psychology of MCS

Abstract:

Neurological symptoms are frequently reported by patients with multiple chemical sensitivities (MCS). Methods to compare the psychiatric, personality, and neuropsychological function of patients with MCS, chronic fatigue syndrome (CFS), and normal controls are described. Increased rates of Axis I psychiatric diagnoses are observed in the literature for MCS and CFS subjects relative to controls.

Findings on the MMPI-2 and the Toronto Alexithymia Scale reveal profiles consistent with the tendency to report somatic rather than emotional symptoms in response to stress. However, many of the reported somatic symptoms also coincide with those found in neurologic disorders. The overall neuropsychological profile for MCS subjects does not reflect cognitive impairment.

Relative to normal controls, the only difference in neuropsychological performance observed is reduced recognition of nontarget designs on a visual memory task. More fruitful areas for future psychological research will include measurement of the interaction between behavioral response styles and attentional processes in cognition, as well as observations under controlled challenge conditions.

Source: Fiedler N, Kipen H, Deluca J, Kelly-McNeil K, Natelson B. Neuropsychology and psychology of MCS. Toxicol Ind Health. 1994 Jul-Oct;10(4-5):545-54. http://www.ncbi.nlm.nih.gov/pubmed/7778113

Chronic fatigue syndrome

Note: This letter was written in response to a letter published in the Canadian Medical Association Journal on May 1, 1989. You can read Holland’s letter here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1268972/pdf/cmaj00190-0022b.pdf

It is regrettable that the publication of an earlier letter from one of us (G.H.R.) and Dr. Jean A. Monro (Can Med Assocj 1989; 140: 361) generated surprise (and apparent disapproval of CMAJ’s action) on the part of Dr. Ray Holland (ibid 1016).

In expressing his disagreement with the use of the term “chronic fatigue syndrome” Holland also appears to be at odds with the US Centers for Disease Control (CDC), whose case definition for this condition (1) was the main point of the earlier letter. We have no disagreement with Holland that “there are also primary psychologic causes of chronic fatigue”. However, the CDC case definition specifically calls for the exclusion of clinical conditions, including psychiatric disease, that may produce similar symptoms.

The whole issue of what triggers psychologic symptoms or illness, however, is an important related matter. Holland reports, quite rightly, that panic disorder appears to be increasingly common. As physicians we have been led to assume that panic disorder has a psychologic origin rather than identifiable extrinsic causes. At the Environmental Health Center – Dallas we have confirmed that panic attacks and other emotional responses may be reproducibly triggered by double-blind testing for sensitivities to foods, inhalants and chemicals. (2)

Similar behavioural effects have been seen in pesticide poisoning (3) and with exposure to other environmental toxins. (4) Specifically, panic attacks have been cited in the psychiatric literature as being triggered by solvent exposure. (5’6)

Being unable to find physical diagnoses for chronic fatigue does not necessarily mean that psychologic illness is the cause. It may simply be that our understanding of the factors precipitating the illness is far from complete. Medical history teaches us that once physical causes for “psychologic” symptoms are discovered the condition moves, as if by magic, from the psychiatric to the medical realm. A good example of this is the relief of behavioural symptoms by correction of thiamin (7) or cobalamin (8) deficiency.

It is our experience that a substantial percentage of chronic fatigue cases (not a minuscule percentage, as Holland suggests) may arise from or be worsened by adverse reactions to components of the patient’s total environment, such as food, inhalants and chemicals.

~Gerald H. Ross, MD, CCFP Fellow in environmental medicine

~William J. Rea, MD, FACS, FAAEM Medical director

~Alfred R. Johnson, DO, FAAEM Environmental Health Center – Dallas; Dallas, Texas

References

1. Holmes GP, Kaplan JE, Gantz NM et al: Chronic fatigue syndrome: a working case definition. Ann Intern Med 1988; 108: 387-389
2. King DS: Can allergic exposure provoke psychological symptoms? A double-blind test. Biol Psychiatry 1981; 16:3-19
3. Rea Wl, Butler JR, Laseter JL et al: Pesticides and brain function changes in a controlled environment. Clin Ecol 1984; 2:145-150
4. Fein GG, Schwartz PM, Jacobson SW et al: Environmental toxins and behavioral development: a new role for psychological research. Am Psychologist 1983; 38: 1188-1197
5. Dager SR, Holland JP, Cowley DS et al: Panic disorder precipitated by exposure to organic solvents in the work place. Am I Psychiatry 1987; 144:1056-1058
6. Lindstrom K, Ruhimake H, Hamminen K: Occupational solvent exposure and neuropsychiatric disorders. Scand J Work Environ Health 1984; 10: 321-323
7. McLaren DS: Clinical manifestations of nutritional disorders. In Shils ME, Young VR (eds): Modem Nutrition in Health and Disease, Lea and Febiger, Philadelphia, 1988: 733-745
8. Lindenbaum J, Healton EB, Savage DG, et al: Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis. N EnglJ Med 1988; 318: 1720-1729

Source: G H Ross, W J Rea, and A R Johnson. Chronic fatigue syndrome. CMAJ. 1989 Jul 1; 141(1): 11–12. PMCID: PMC1269261 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1269261/