Information processing in chronic fatigue syndrome: a preliminary investigation of suggestibility

Abstract:

This study examines the effects of certain types of information processing on the subjective experience of cognitive deficits in persons with chronic fatigue syndrome (CFS).

Two groups of participants, persons with CFS and a group of healthy controls, were administered a symptom inventory and measures of intellectual functioning, memory, automatic processing, and suggestibility. The groups differed significantly on number and severity of reported symptoms and on measures of global suggestibility and automatic processing, but not on measures of intellectual functioning and memory.

Suggestibility was related to number and severity of reported symptoms, as well as the inability to inhibit the automatic processing of information. Implications of these findings are discussed, as well as directions for future research and treatment of symptoms associated with CFS.

 

Source: DiClementi JD, Schmaling KB, Jones JF. Information processing in chronic fatigue syndrome: a preliminary investigation of suggestibility. J Psychosom Res. 2001 Nov;51(5):679-86. http://www.ncbi.nlm.nih.gov/pubmed/11728509

 

The neuroendocrinology of chronic fatigue syndrome and fibromyalgia

Abstract:

BACKGROUND: Disturbance of the HPA axis may be important in the pathophysiology of chronic fatigue syndrome (CFS) and fibromyalgia. Symptoms may be due to: (1) low circulating cortisol; (2) disturbance of central neurotransmitters; or (3) disturbance of the relationship between cortisol and central neurotransmitter function. Accumulating evidence of the complex relationship between cortisol and 5-HT function, make some form of hypothesis (3) most likely. We review the methodology and results of studies of the HPA and other neuroendocrine axes in CFS.

METHOD: Medline, Embase and Psychlit were searched using the Cochrane Collaboration strategy. A search was also performed on the King’s College CFS database, which includes over 3000 relevant references, and a citation analysis was run on the key paper (Demitrack et al. 1991).

RESULTS: One-third of the studies reporting baseline cortisol found it to be significantly low, usually in one-third of patients. Methodological differences may account for some of the varying results. More consistent is the finding of reduced HPA function, and enhanced 5-HT function on neuroendocrine challenge tests. The opioid system, and arginine vasopressin (AVP) may also be abnormal, though the growth hormone (GH) axis appears to be intact, in CFS.

CONCLUSIONS: The significance of these changes, remains unclear. We have little understanding of how neuroendocrine changes relate to the experience of symptoms, and it is unclear whether these changes are primary, or secondary to behavioural changes in sleep or exercise. Longitudinal studies of populations at risk for CFS will help to resolve these issues.

 

Source: Parker AJ, Wessely S, Cleare AJ. The neuroendocrinology of chronic fatigue syndrome and fibromyalgia. Psychol Med. 2001 Nov;31(8):1331-45. http://www.ncbi.nlm.nih.gov/pubmed/11722149

 

A twin study of chronic fatigue

Abstract:

OBJECTIVE: The etiology of chronic fatigue syndrome is unknown, but genetic influences may be important in its expression. Our objective was to assess the role of genetic and environmental factors in unexplained chronic fatigue.

METHODS: A classic twin study was conducted using 146 female-female twin pairs, of whom at least one member reported > or =6 months of fatigue. After completing questionnaires on symptoms, zygosity, physical health, and a psychiatric interview, twins were classified using three increasingly stringent definitions: 1) chronic fatigue for > or =6 months, 2) chronic fatigue not explained by exclusionary medical conditions, and 3) idiopathic chronic fatigue not explained by medical or psychiatric exclusionary criteria of the chronic fatigue syndrome case definition. Concordance rates in monozygotic and dizygotic twins were calculated for each fatigue definition along with estimates of the relative magnitude of genetic and environmental influences on chronic fatigue.

RESULTS: The concordance rate was higher in monozygotic than dizygotic twins for each definition of chronic fatigue. For idiopathic chronic fatigue, the concordance rates were 55% in monozygotic and 19% in dizygotic twins (p =.042). The estimated heritability in liability was 19% (95% confidence interval = 0-56) for chronic fatigue > or =6 months, 30% (95% confidence interval = 0-81) for chronic fatigue not explained by medical conditions, and 51% (95% confidence interval = 7-96) for idiopathic chronic fatigue.

CONCLUSIONS: These results provide evidence supporting the familial aggregation of fatigue and suggest that genes may play a role in the etiology of chronic fatigue syndrome.

 

Source: Buchwald D, Herrell R, Ashton S, Belcourt M, Schmaling K, Sullivan P, Neale M, Goldberg J. A twin study of chronic fatigue. Psychosom Med. 2001 Nov-Dec;63(6):936-43. http://www.ncbi.nlm.nih.gov/pubmed/11719632

 

Circulating tumour necrosis factor-alpha and interferon-gamma are detectable during acute and convalescent parvovirus B19 infection and are associated with prolonged and chronic fatigue

Abstract:

To investigate whether cytokine responses may have a bearing on the symptoms and outcome of parvovirus B19 infection, circulating cytokines were measured during acute infection (n=51), follow-up of acute infection (n=39) and in normal healthy controls (n=50).

At acute B19 virus infection (serum anti-B19 IgM-positive), patients ranged in age from 4 to 54 years, with a mean age of 28.2 years. The male:female ratio was 1:4.1 and symptoms were rash (n=15), arthralgia (n=31), fatigue (n=8), lymphadenopathy (n=4), foetal hydrops (n=3), transient aplastic crisis (n=2), neutropenia (n=2), myelodysplasia (n=1), thrombocytopenia (n=1) and pancytopenia (n=1). Of these patients, 39 were contacted after a follow-up period of 2-37 months (mean of 22.5 months).

In comparison with normal controls, detectable IL-6 was associated with acute B19 virus infection (26%; P=0.0003), but not with follow-up (6%; P=0.16). Detection of interferon (IFN)-gamma was associated with acute B19 virus infection (67%; P<0.0001) and follow-up (67%; P<0.0001). Detection of tumour necrosis factor (TNF)-alpha was associated with acute B19 virus infection (49%; P<0.0001) and follow-up (56%; P<0.0001). IL-1beta was detected in acute infection (20%), but not at follow-up. At acute B19 virus infection, detection of serum/plasma IL-6 was associated with rheumatoid factor (P=0.038) and IFN-gamma (> or =7 pg/ml) was associated with fatigue in those patients of > or =15 years of age (P=0.022). At follow-up, fatigue was associated with IFN-gamma (> or =7 pg/ml) and/or TNF-alpha (> or =40 pg/ml) (P=0.0275).

Prolonged upregulation of serum IFN-gamma and TNF-alpha appears to represent a consistent host response to symptomatic B19 virus infection.

 

Source: Kerr JR, Barah F, Mattey DL, Laing I, Hopkins SJ, Hutchinson IV, Tyrrell DA. Circulating tumour necrosis factor-alpha and interferon-gamma are detectable during acute and convalescent parvovirus B19 infection and are associated with prolonged and chronic fatigue. J Gen Virol. 2001 Dec;82(Pt 12):3011-9. http://www.ncbi.nlm.nih.gov/pubmed/11714978

 

Sexual abuse, physical abuse, chronic fatigue, and chronic fatigue syndrome: a community-based study

Abstract:

Using a randomly selected community-based sample, this investigation examined whether histories of childhood sexual, physical, and death threat abuse predicted adulthood outcomes of specific medical and psychiatric conditions involving chronic fatigue. This study also tested prior suggestions that most individuals with chronic fatigue syndrome report a past history of interpersonal abuse.

Multinomial logistic regression was used to examine the relationship between abuse history and chronic fatigue group outcomes while controlling for the effects of sociodemographics. Compared with healthy controls, childhood sexual abuse was significantly more likely to be associated with outcomes of idiopathic chronic fatigue, chronic fatigue explained by a psychiatric condition, and chronic fatigue explained by a medical condition. None of the abuse history types were significant predictors of chronic fatigue syndrome.

A closer examination of individuals in the chronic fatigue syndrome group revealed that significantly fewer individuals with CFS reported abuse as compared with those who did not. The implications of these findings are discussed.

 

Source: Taylor RR, Jason LA. Sexual abuse, physical abuse, chronic fatigue, and chronic fatigue syndrome: a community-based study. J Nerv Ment Dis. 2001 Oct;189(10):709-15. http://www.ncbi.nlm.nih.gov/pubmed/11708672

 

Chronic fatigue syndrome: oxidative stress and dietary modifications

Abstract:

Chronic fatigue syndrome (CFS) is an illness characterized by persistent and relapsing fatigue, often accompanied by numerous symptoms involving various body systems. The etiology of CFS remains unclear; however, a number of recent studies have shown oxidative stress may be involved in its pathogenesis. The role of oxidative stress in CFS is an important area for current and future research as it suggests the use of antioxidants in the management of CFS.

Specifically, the dietary supplements glutathione, N-acetylcysteine, alpha-lipoic acid, oligomeric proanthocyanidins, Ginkgo biloba, and Vaccinium myrtillus (bilberry) may be beneficial. In addition, research on food intolerance is discussed, since food intolerance may be involved in CFS symptom presentation and in oxidation via cytokine induction.

Finally, recent evidence suggests celiac disease can present with neurological symptoms in the absence of gastrointestinal symptoms; therefore, celiac disease should be included in the differential diagnosis of CFS.

 

Source: Logan AC, Wong C. Chronic fatigue syndrome: oxidative stress and dietary modifications. Altern Med Rev. 2001 Oct;6(5):450-9. http://www.ncbi.nlm.nih.gov/pubmed/11703165

 

A family history study of chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is characterized by unexplained, disabling fatigue and is associated with high rates of comorbid depression. While the aetiology is unknown, findings from recent twin surveys suggest that genetic factors may be relevant to prolonged fatigue states (> 1 month). To date, however, there has been no exploration of the role of familial/genetic factors in operationally defined CFS.

The aims of the present study were: (i) to examine whether CFS is familial by comparing the rates of CFS in the first-degree relatives of CFS cases and medical control subjects; and (ii) to determine whether the high rate of comorbid depression in CFS is reflected in a greater familial loading for affective disorder.

Twenty-five CFS cases and 36 medical control subjects were assessed for fatigue symptoms based on the Centre for Disease Control (CDC) criteria for CFS, and for lifetime psychiatric symptoms using the Schedule for Schizophrenia and Affective Disorders-Lifetime Version. Informant family history was obtained regarding first-degree relatives using the CDC criteria and the Family History Research Diagnostic Criteria. In addition, informant history was supplemented by sending a questionnaire to first-degree relatives.

There were significantly higher rates of CFS in the relatives of CFS cases compared with the relatives of control subjects. The rate of depression in the CFS cases was similar to previous studies but did not appear to reflect a greater familial loading for depression when compared with control subjects. However, these analyses were complicated by higher than expected rates of depression in the control group. These findings suggest that familial factors are important in the aetiology of chronic fatigue syndrome.

 

Source: Walsh CM, Zainal NZ, Middleton SJ, Paykel ES. A family history study of chronic fatigue syndrome. Psychiatr Genet. 2001 Sep;11(3):123-8. http://www.ncbi.nlm.nih.gov/pubmed/11702053

 

Antiviral pathway activation in patients with chronic fatigue syndrome and acute infection

Abstract:

Gene expression of key enzymes in 2 antiviral pathways (ribonuclease latent [RNase L] and RNA-regulated protein kinase [PKR]) was compared in 22 patients with chronic fatigue syndrome (CFS), 10 patients with acute gastroenteritis, and 21 healthy volunteers. Pathway activation in the group of patients with infections differed significantly from that of the other 2 groups, in whom there was no evidence of upregulation. Therefore, assay of activation is unlikely to provide the basis for a diagnostic test for CFS.

Comment in: Antiviral pathway activation in chronic fatigue syndrome and acute infection. [Clin Infect Dis. 2002]

 

Source: Gow JW, Simpson K, Behan PO, Chaudhuri A, McKay IC, Behan WM. Antiviral pathway activation in patients with chronic fatigue syndrome and acute infection. Clin Infect Dis. 2001 Dec 15;33(12):2080-1. Epub 2001 Nov 6. http://cid.oxfordjournals.org/content/33/12/2080.long (Full article)

 

Chronic fatigue

The possibility that fatigue may be an early manifestation of a serious medical illness not elicited through blood testing has been investigated by monitoring fatigued patients prospectively over time for the development of new diagnoses. At 1 year of follow-up, one study 3 showed no significant differences in new diagnoses, the incidences of diagnosed cancers, number of physician visits, or number of hospital admissions or hospital days.

This gives more weight to the conclusion that patients with chronic fatigue who otherwise have normal histories and no abnormalities on physical examination do not require extensive workups for occult medical illnesses.

You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1071607/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1071607/

 

Source: Stevens DL. Chronic fatigue. West J Med. 2001 Nov;175(5):315-9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1071607/ (Full article)

 

Autonomic nervous system derangement in fibromyalgia syndrome and related disorders

Abstract:

Fibromyalgia syndrome is a chronic, painful musculoskeletal disorder of unknown etiology and/or pathophysiology. During the last decade many studies have suggested autonomic nervous system involvement in this syndrome, although contradictory results have been reported. This review focuses on studies of the autonomic nervous system in fibromyalgia syndrome and related disorders, such as chronic fatigue syndrome and irritable bowel syndrome on the one hand and anxiety disorder on the other, and highlights techniques of dynamic assessment of heart rate variability. It raises the potentially important prognostic implications of protracted autonomic dysfunction in patient populations with fibromyalgia and related disorders, especially for cardiovascular morbidity and mortality.

 

Source: Cohen H, Neumann L, Kotler M, Buskila D. Autonomic nervous system derangement in fibromyalgia syndrome and related disorders. Isr Med Assoc J. 2001 Oct;3(10):755-60. http://www.ncbi.nlm.nih.gov/pubmed/11692551