Neuroendocrine correlates of chronic fatigue syndrome: a brief review

Abstract:

Chronic fatigue syndrome remains one of the more perplexing syndromes in contemporary clinical medicine. One approach to understanding this condition has been to acknowledge its similarities to other disorders of clearer pathophysiology.

In this review, a rationale for the study of neuroendocrine correlates of chronic fatigue syndrome is presented, based in part on the clinical observation that asthenic or fatigue states share many of the somatic symptom characteristics seen in recognized endocrine disorders. Of additional interest is the observation that psychological symptoms, particularly disturbances in mood and anxiety, are equally prominent in this condition.

At this time, several reports have provided replicated evidence of disruptions in the integrity of the hypothalamic-pituitary-adrenal axis in patients with chronic fatigue syndrome. It is notable that the pattern of the alteration in the stress response apparatus is not reminiscent of the well-understood hypercortisolism of melancholic depression but, rather, suggests a sustained inactivation of central nervous system components of this system.

Recent work also implicates alterations in central serotonergic tone in the overall pathophysiology of this finding. The implications of these observations are far from clear, but they highlight the fact that, though chronic fatigue syndrome overlaps with the well-described illness category of major depression, these are not identical clinical conditions.

 

Source: Demitrack MA. Neuroendocrine correlates of chronic fatigue syndrome: a brief review. J Psychiatr Res. 1997 Jan-Feb;31(1):69-82. http://www.ncbi.nlm.nih.gov/pubmed/9201649

 

Increased prolactin response to buspirone in chronic fatigue syndrome

Abstract:

We studied the endocrine and subjective responses that followed acute administration of the 5-HT1A receptor agonist buspirone (0.5 mg/kg orally) in 11 male patients with chronic fatigue syndrome (CFS) and a group of matched healthy controls.

Patients with CFS had significantly higher plasma prolactin concentrations and experienced more nausea in response to buspirone than did controls. However, the growth hormone response to buspirone did not distinguish CFS patients from controls.

Our data question whether the enhancement of buspirone-induced prolactin release in CFS is a consequence of increased sensitivity of post-synaptic 5-HT1A receptors. It is possible that the increased prolactin response to buspirone in CFS could reflect changes in dopamine function.

 

Source: Sharpe M, Clements A, Hawton K, Young AH, Sargent P, Cowen PJ. Increased prolactin response to buspirone in chronic fatigue syndrome. J Affect Disord. 1996 Nov 4;41(1):71-6. http://www.ncbi.nlm.nih.gov/pubmed/8938208

 

Neuroendocrine assessment of serotonin (5-HT) function in chronic fatigue syndrome

Abstract:

Prolactin and cortisol responses to dl-fenfluramine challenge were examined in 11 patients with chronic fatigue syndrome and in 11 healthy controls who were age and gender matched. After obtaining two baseline samples, each subject was given 60 mg of dl-fenfluramine orally and further blood samples were drawn hourly during the following five hours in order to measure prolactin and cortisol levels. There was no difference in either baseline or fenfluramine-induced hormonal responses between patients with chronic fatigue syndrome and controls. There was also no correlation between depression scores on HAM-D and hormonal responses in patients with chronic fatigue syndrome. The findings of this study do not support a role for 5-HT in chronic fatigue syndrome.

Comment in: Re: Endocrine responses to fenfluramine challenge in chronic fatigue syndrome. [Can J Psychiatry. 1996]

 

Source: Yatham LN, Morehouse RL, Chisholm BT, Haase DA, MacDonald DD, Marrie TJ. Neuroendocrine assessment of serotonin (5-HT) function in chronic fatigue syndrome. Can J Psychiatry. 1995 Mar;40(2):93-6. http://www.ncbi.nlm.nih.gov/pubmed/7788624

 

Pharmacological approaches to the therapy of chronic fatigue syndrome

Abstract:

Although a variety of pharmacological agents have been used to treat patients with chronic fatigue syndrome none has been shown to effect a complete resolution of symptoms.

Data obtained from a retrospective study and from an objective assessment of the aerobic work capacity of patients with this disorder suggest that the underlying pathophysiological abnormality is a disorder of sleep regulation. This results not only in profound fatigue and lethargy but also reduced sensory threshold for pain, disordered temperature regulation, cardiovascular abnormalities, disturbed higher cerebral function and mental depression.

Drugs which modulate sleep, such as tricyclic antidepressants, have a limited effect in improving the symptoms that CFS patients experience. We suggest that other agents which affect central nervous system neurotransmitters, particularly serotonin, may have potential in the management of this condition and need to be evaluated in large controlled clinical trials.

 

Source: McCluskey DR. Pharmacological approaches to the therapy of chronic fatigue syndrome. Ciba Found Symp. 1993;173:280-7; discussion 287-97. http://www.ncbi.nlm.nih.gov/pubmed/8491103