Risk Factors

Risk Factors

In studies of large patient groups, 15 - 27% of people complain of long-term fatigue, but the majority can be explained by other medical or psychological problems. According to surveys, chronic fatigue syndrome (CFS) itself affects over four in every 1,000 Americans. It occurs in both sexes and at all ages and in all racial and ethnic groups. The CDC estimates 1 million people in the U.S. have the disease, but only 20% of people with CFS may be properly diagnosed. Nevertheless, the true prevalence of CFS is very difficult to determine, since an accurate diagnosis is difficult to obtain.

Age and Gender

Chronic fatigue is most often experienced by individuals 40 - 50 years old. Studies have found that four times the number of women than men have CFS, although women do not appear to have more severe symptoms than men with the disorder. Children and adolescents are not immune to its effects. Most studies indicate that girls are more likely to develop CFS than boys, although one study found the incidence of the syndrome to be equal.

Culture and Social Levels

Some studies report that CFS rates are highest in minority groups (African and Hispanic Americans), and people with lower levels of education and occupational status. Other studies found higher rates of CFS in Caucasian women than in women from other ethnic groups. However, this may reflect the greater socioeconomic ability of Caucasian women to seek treatment.

Depression and Psychological Factors

The link between psychological disorders and chronic fatigue syndrome is problematic because so many of the symptoms overlap. The rates of depression are very high in CFS patients. In one study, 27.4% of patients diagnosed with CFS alone also had a history of depression. (Depression rates were significantly higher in CFS patients who had other conditions, notably fibromyalgia and multiple chemical sensitivity.)

Studies also report that most children and adolescents with CFS suffer psychiatric disorders. Some evidence suggests that psychological factors during childhood may increase susceptibility for later CFS, although these factors are not consistent. For example, in a small 2003 survey, CFS patients tended to have mothers who were overprotective and depressed. In another small study, five out of 13 patients reported sexual or physical abuse during childhood. The bottom line is that studies have not found any consistent association between emotional or personality disorders and CFS to explain any causal role. Some may however, serve as a risk factor for CFS.