Urinary free cortisol in chronic fatigue syndrome.
OBJECTIVE
The authors measured 24-hour urinary free cortisol in a group of well-characterized patients with chronic fatigue syndrome.


METHODS
They obtained 24-hour urine collections from 121 consecutive clinic patients with chronic fatigue syndrome and 64 comparison subjects without the syndrome.


RESULTS
Urinary free cortisol was significantly lower in the subjects with chronic fatigue syndrome regardless of the presence or absence of current or past comorbid psychiatric illness. Lower levels of urinary free cortisol were not related to medication use, sleep disturbance, or disability levels.


CONCLUSIONS
There is mild hypocortisolism in chronic fatigue syndrome. Whether a primary feature or secondary to other factors, hypocortisolism may be one factor contributing to the symptoms of chronic fatigue syndrome.
Department of Psychological Medicine, Guy's King's and St. Thomas' School of Medicine and the Institute of Psychiatry, 103 Denmark Hill, London SE5 8AZ, UK. a.cleare@iop.kcl.ac.uk
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AJ
Cleare
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Blair
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Chambers
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Wessely
D000328:Adult; D002940:Circadian Rhythm; D015897:Comorbidity; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000453:epidemiology / Q000652:urine*; D005260:Female; D006304:Health Status; D006801:Humans; D006854:Hydrocortisone / Q000652:urine*; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000652:urine; D012893:Sleep Wake Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000652:urine; D011795:Surveys and Questionnaires
D006854:Hydrocortisone