Study participants diagnosed with chronic fatigue syndrome had to have experienced medically unexplainable fatigue that limited their daily activities for at least six months with four of the following symptoms: headache, muscle pain, joint pain, sore throat, tender lymph nodes, significant impairment of memory or concentration, unrefreshing sleep, and unusual postexertional malaise.

The study, published in Psychotherapy and Psychosomatics, found that chronic fatigue syndrome victims scored higher in neuroticism, a measure of vulnerability to negative emotional states such as anxiety or depression, than both people without fatigue and people with medically unexplainable fatigue. Victims of medically unexplainable fatigue, however, still scored higher in neuroticism scores than people without fatigue. The researchers also found a reverse pattern with extraversion, one’s level of activity and sociability. Chronic fatigue syndrome victims were the least extraverted, and people without fatigue were the most extraverted. Although these results were solely correlational, in another study, chronic fatigue syndrome patients rated themselves as higher on neuroticism and lower in extraversion when they were ill then when they were well.

The reduced levels of extraversion may indeed be a result of fatigue rather than a risk factor for fatigue. It is possible that neuroticism is also either a result of the fatigue itself or a result of the same factors which are causing the fatigue. On a psychological level, chronic fatigue may lead to greater emotional burden due to feelings such as worry, frustration, and aloneness that victims of chronic unexplainable fatigue often experience. This emotional burden might, in turn, lead to higher neuroticism scores. Chronic fatigue could alse cause or be the result of an impaired physiological response to stress.

The two groups of participants with chronic fatigue had similar levels of agreeableness and conscientiousness which were lower than the scores of people without fatigue. Agreeableness is a measure of the tendency to be cooperative and compassionate towards others, and conscientiousness is a measure of such traits as being organized, planful, and self-disciplined. Whether agreeableness and conscientiousness decrease after onset of the chronic fatigue or are risk factors for chronic fatigue is unclear.

The study also found that a disproportionately large number of chronic fatigue victims had personality disorders, or maladaptive behavior patterns. Twenty-nine percent of people with unexplainable fatigue and 28 percent of people with chronic fatigue syndrome had at least one personality disorder. The most common personality disorder found among people with chronic fatigue syndrome was obsessive-compulsive personality disorder, a personalitydisorder involving a maladaptive obsession with perfection, rules, and organization. Maladaptive behavior patterns may in fact be risk factors for developing chronic fatigue. A past study followed sets of twins for 25 years and found that high stress and emotional instability, which are both causes and results of maladaptive behavior patterns, increased the risk for developing chronic fatigue-like illness.

Interestingly, another study examined patients with multiple sclerosis, a fatiguing illness which, like chronic fatigue syndrome, has an unknown cause, and found that the multiple sclerosis patients had about as many personality disorders as the chronic fatigue syndrome patients. Maladaptive behavior patterns thus may be risk factors for both chronic fatigue and multiple sclerosis.

Although about a quarter of people with chronic fatigue syndrome are disabled enough that they are either unemployed or receiving disability compensation, only about half of people with this disorder actually consult a physician about their illness. This can perhaps be partly attributed to the lack of knowledge among physicians about the nature of unexplainable chronic fatigue as well as to the limited number of current treatments. Understanding the personality behind chronic fatigue will bring the victims of medically unexplainable chronic fatigue one step closer to getting proper help.

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