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Winter 2002

Research Briefs

Following is news of current publications and research efforts underway related to chronic fatigue syndrome (CFS) — also called chronic fatigue and immune dysfunction syndrome (CFIDS).

New standards for diagnosis?
CFS is diagnosed using the U.S. Centers for Disease Control and Prevention (CDC) 1994 International Case Definition, also known as the Fukuda definition. New community-based research has confirmed many of the major criteria in the definition, and suggests additional symptoms that may help with diagnosis.

The study looked at 32 people with CFS, 19 with melancholic depression and 44 healthy controls. The subjects had all undergone physical and psychiatric examinations to diagnose their conditions or exclude them from a diagnosis of CFS.

Several cardiopulmonary and neurological symptoms occurred with significantly greater frequency in CFS patients than the control groups—including shortness of breath (65.6% vs. 22.7%), chest pain (40.6% vs. 6.8%), dizziness after standing (46.9% vs. 9.1%), general dizziness (43.8% vs. 2.3%) and alcohol intolerance (43.8% vs. 6.8%).

While the study size was small, the authors suggest that more research could prove the value of adding these symptoms to the case definition of CFS to help refine and improve the diagnostic criteria.
Jason LA et al. “Symptom occurrence in persons with chronic fatigue syndrome.” Biological Psychology. 2002; 59(1): 15-27.

CFS, anxiety link not genetic
Depression, anxiety and other mood disorders are common comorbid conditions in patients with chronic fatigue syndrome. New research on twins suggests that environmental factors, not genetic ones, may lie behind this association.

One hundred twin pairs discordant for chronic fatigue were studied, including 69 monozygotic and 31 dizygotic pairs. All test subjects were white females. The subjects were asked to complete the General Health Questionnaire (GHQ), a 28-item self-report that measures psychological and somatic distress on a four-point scale.

Analysis of the questionnaires found that the twins who suffered from chronic fatigue showed significantly higher measures for anxiety and somatic preoccupation regardless of zygosity. Monozygotic twins with chronic fatigue also were more likely to show symptoms of social dysfunction and depression.

The authors say their data suggest no genetic basis for the link between CFS and the comorbid psychological conditions, since the non-fatigued twins with identical genes did not show similar levels of distress. The association may be due to environmental factors, or could be due to overlapping definitions for CFS and the other conditions.

Roy-Byrne P et al. “Chronic fatigue and anxiety/depression: a twin study.” British Journal of Psychiatry. Jan. 2002; 180:29-34.