Melatonin levels in women with fibromyalgia (FM) & Chronic Fatigue Syndrome (CFS)

OBJECTIVE: Fibromyalgia (FM) and chronic fatigue syndrome

(CFS) are stress associated disorders mainly affecting women.

FM is characterized primarily by widespread musculoskeletal

pain, and CFS by profound debilitating fatigue, but there is

considerable overlap of clinical symptoms between these 2

syndromes. Neuroendocrine abnormalities have been noted in

both FM and CFS and desynchronization of circadian systems has

been postulated in their etiology. The pineal hormone

melatonin is involved in synchronizing circadian systems and

the use of exogenous melatonin has become widespread in

patients with FM and CFS.

METHODS: We examined the

characteristics and relationship of melatonin and cortisol

levels in premenopausal women with FM (n = 9) or CFS (n = 8),

compared to age and menstrual cycle phase matched controls.

Blood was collected from an indwelling intravenous catheter

every 10 min over 24 h, and plasma melatonin and cortisol were

determined by radioimmunoassay at 60 and 10 min intervals,


RESULTS: Night time (23:00-06:50) plasma

melatonin levels were significantly higher in FM patients

compared to controls (p<0.05), but there was no significant

difference in melatonin levels between CFS patients and

controls. No differences in the timing of cortisol and

melatonin secretory patterns and no internal desynchronization

of the 2 rhythms were found in either patient group, compared

to controls.

CONCLUSION: Raised plasma melatonin

concentrations have been documented in several other

conditions that are associated with dysregulation of

neuroendocrine axes. Increased melatonin levels may represent

a marker of increased susceptibility to stress induced

hypothalamic disruptions. These data indicate that there is no

rationale for melatonin replacement therapy in patients with

FM and CFS.

Korszun A, Sackett-Lundeen L, Papadopoulos E, Brucksch C, Masterson

L, Engelberg NC, Haus E, Demitrack MA, Crofford L

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