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Volume 2013 (2013), Article ID 784520, 8 pages
http://dx.doi.org/10.1155/2013/784520
Review Article

A Review of Hypothalamic-Pituitary-Adrenal Axis Function in Chronic Fatigue Syndrome

1Newcastle University, Newcastle upon Tyne NE1 7RU, UK
2Wolfson Research Centre, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK

Received 28 June 2013; Accepted 29 August 2013

Academic Editors: C. Bishop, P. de Gortari, G. Forster, and G. Hans

Copyright © 2013 Cara Tomas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. A. Chaudhuri and P. O. Behan, “Neurological dysfunction in chronic fatigue syndrome,” Journal of Chronic Fatigue Syndrome, vol. 6, no. 3-4, pp. 51–68, 2000. View at Scopus
  2. H. C. Atkinson, J. D. Leggett, S. A. Wood, E. S. Castrique, Y. M. Kershaw, and S. L. Lightman, “Regulation of the hypothalamic-pituitary-adrenal axis circadian rhythm by endocannabinoids is sexually diergic,” Endocrinology, vol. 151, no. 8, pp. 3720–3727, 2010. View at Publisher · View at Google Scholar · View at Scopus
  3. J. E. Ottenweller, S. A. Sisto, R. C. McCarty, and B. H. Natelson, “Hormonal responses to exercise in chronic fatigue syndrome,” Neuropsychobiology, vol. 43, no. 1, pp. 34–41, 2001. View at Publisher · View at Google Scholar · View at Scopus
  4. B. Van Houdenhove, F. V. D. Eede, and P. Luyten, “Does hypothalamic-pituitary-adrenal axis hypofunction in chronic fatigue syndrome reflect a 'crash' in the stress system?” Medical Hypotheses, vol. 72, no. 6, pp. 701–705, 2009. View at Publisher · View at Google Scholar · View at Scopus
  5. K. Fukuda, S. E. Straus, I. Hickie, M. C. Sharpe, J. G. Dobbins, and A. Komaroff, “The chronic fatigue syndrome: a comprehensive approach to its definition and study,” Annals of Internal Medicine, vol. 121, no. 12, pp. 953–959, 1994. View at Scopus
  6. M. C. Sharpe, L. C. Archard, J. E. Banatvala et al., “A report—chronic fatigue syndrome: guidelines for research,” Journal of the Royal Society of Medicine, vol. 84, no. 2, pp. 118–121, 1991.
  7. B. M. Carruthers, M. I. Van de Sande, K. L. De Meirleir et al., “Myalgic encephalomyelitis: international Consensus Criteria,” Journal of Internal Medicine, vol. 270, no. 4, pp. 327–338, 2011. View at Publisher · View at Google Scholar · View at Scopus
  8. A. S. Papadopoulos and A. J. Cleare, “Hypothalamic-pituitary-adrenal axis dysfunction in chronic fatigue syndrome,” Nature Reviews Endocrinology, vol. 8, no. 1, pp. 22–32, 2012. View at Publisher · View at Google Scholar · View at Scopus
  9. J. R. V. Usón and M. Á. I. Alecha, “Diagnostic and treatment challenges of chronic fatigue syndrome: role of immediate-release methylphenidate,” Expert Review of Neurotherapeutics, vol. 8, no. 6, pp. 917–927, 2008. View at Publisher · View at Google Scholar · View at Scopus
  10. A. Beaumont, A. R. Burton, J. Lemon, B. K. Bennett, A. Lloyd, and U. Vollmer-Conna, “Reduced cardiac vagal modulation impacts on cognitive performance in chronic fatigue syndrome,” PLoS ONE, vol. 7, no. 11, Article ID e49518, 2012. View at Publisher · View at Google Scholar
  11. S. M. Smith and W. W. Vale, “The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress,” Dialogues in Clinical Neuroscience, vol. 8, no. 4, pp. 383–395, 2006. View at Scopus
  12. I. J. Elenkov and G. P. Chrousos, “Stress system: organization, physiology and immunoregulation,” NeuroImmunoModulation, vol. 13, no. 5-6, pp. 257–267, 2007. View at Publisher · View at Google Scholar · View at Scopus
  13. L. Lanfumey, R. Mongeau, C. Cohen-Salmon, and M. Hamon, “Corticosteroid-serotonin interactions in the neurobiological mechanisms of stress-related disorders,” Neuroscience and Biobehavioral Reviews, vol. 32, no. 6, pp. 1174–1184, 2008. View at Publisher · View at Google Scholar · View at Scopus
  14. L. Jason, M. Sorenson, K. Sebally et al., “Increased HDAC in association with decreased plasma cortisol in older adults with chronic fatigue syndrome,” Brain, Behavior, and Immunity, vol. 25, no. 8, pp. 1544–1547, 2011. View at Publisher · View at Google Scholar · View at Scopus
  15. B. M. Kudielka, N. C. Schommer, D. H. Hellhammer, and C. Kirschbaum, “Acute HPA axis responses, heart rate, and mood changes to psychosocial stress (TSST) in humans at different times of day,” Psychoneuroendocrinology, vol. 29, no. 8, pp. 983–992, 2004. View at Publisher · View at Google Scholar · View at Scopus
  16. A. J. Cleare, “The neuroendocrinology of chronic fatigue syndrome,” Endocrine Reviews, vol. 24, no. 2, pp. 236–252, 2003. View at Publisher · View at Google Scholar · View at Scopus
  17. A. M. Bao, G. Meynen, and D. F. Swaab, “The stress system in depression and neurodegeneration: focus on the human hypothalamus,” Brain Research Reviews, vol. 57, no. 2, pp. 531–553, 2008. View at Publisher · View at Google Scholar · View at Scopus
  18. C. M. Pariante and S. L. Lightman, “The HPA axis in major depression: classical theories and new developments,” Trends in Neurosciences, vol. 31, no. 9, pp. 464–468, 2008. View at Publisher · View at Google Scholar · View at Scopus
  19. A. Ben-Zvi, S. D. Vernon, and G. Broderick, “Model-based therapeutic correction of hypothalamic-pituitary-adrenal axis dysfunction,” PLoS Computational Biology, vol. 5, no. 1, Article ID e1000273, 2009. View at Publisher · View at Google Scholar · View at Scopus
  20. J. Gaab, V. Engert, V. Heitz, T. Schad, T. H. Schürmeyer, and U. Ehlert, “Associations between neuroendocrine responses to the Insulin Tolerance Test and patient characteristics in chronic fatigue syndrome,” Journal of Psychosomatic Research, vol. 56, no. 4, pp. 419–424, 2004. View at Publisher · View at Google Scholar · View at Scopus
  21. A. Poteliakhoff, “Adrenocortical activity and some clinical findings in acute and chronic fatigue,” Journal of Psychosomatic Research, vol. 25, no. 2, pp. 91–95, 1981. View at Publisher · View at Google Scholar · View at Scopus
  22. L. M. Tak, A. J. Cleare, J. Ormel et al., “Meta-analysis and meta-regression of hypothalamic-pituitary-adrenal axis activity in functional somatic disorders,” Biological Psychology, vol. 87, no. 2, pp. 183–194, 2011. View at Publisher · View at Google Scholar · View at Scopus
  23. V. B. Wyller, “The chronic fatigue syndrome: an update,” Acta Neurologica Scandinavica, vol. 115, no. 187, pp. 7–14, 2007. View at Publisher · View at Google Scholar · View at Scopus
  24. W. K. Jerjes, A. J. Cleare, S. Wessely, P. J. Wood, and N. F. Taylor, “Diurnal patterns of salivary cortisol and cortisone output in chronic fatigue syndrome,” Journal of Affective Disorders, vol. 87, no. 2-3, pp. 299–304, 2005. View at Publisher · View at Google Scholar · View at Scopus
  25. A. Di Giorgio, M. Hudson, W. Jerjes, and A. J. Cleare, “24-Hour pituitary and adrenal hormone profiles in chronic fatigue syndrome,” Psychosomatic Medicine, vol. 67, no. 3, pp. 433–440, 2005. View at Publisher · View at Google Scholar · View at Scopus
  26. L. J. Crofford, E. A. Young, N. C. Engleberg et al., “Basal circadian and pulsatile ACTH and cortisol secretion in patients with fibromyalgia and/or chronic fatigue syndrome,” Brain, Behavior, and Immunity, vol. 18, no. 4, pp. 314–325, 2004. View at Publisher · View at Google Scholar · View at Scopus
  27. B. S. McEwen, “Central effects of stress hormones in health and disease: understanding the protective and damaging effects of stress and stress mediators,” European Journal of Pharmacology, vol. 583, no. 2-3, pp. 174–185, 2008. View at Publisher · View at Google Scholar · View at Scopus
  28. F. Van Den Eede, G. Moorkens, W. Hulstijn et al., “Combined dexamethasone/corticotropin-releasing factor test in chronic fatigue syndrome,” Psychological Medicine, vol. 38, no. 7, pp. 963–970, 2008. View at Publisher · View at Google Scholar · View at Scopus
  29. W. J. Inder, T. C. R. Prickett, and R. T. Mulder, “Normal opioid tone and hypothalamic-pituitary-adrenal axis function in chronic fatigue syndrome despite marked functional impairment,” Clinical Endocrinology, vol. 62, no. 3, pp. 343–348, 2005. View at Publisher · View at Google Scholar · View at Scopus
  30. H. B. Izgi, C. Gökçe, M. Çaliş et al., “Investigation of the hypothalamopituitary-adrenal axis by low-dose (1 μg) adrenocorticotrophic hormone test and metyrapone test in patients with chronic fatigue syndrome,” Endocrinologist, vol. 15, no. 2, pp. 89–92, 2005. View at Publisher · View at Google Scholar · View at Scopus
  31. J. Gaab, N. Rohleder, V. Heitz et al., “Stress-induced changes in LPS-induced pro-inflammatory cytokine production in chronic fatigue syndrome,” Psychoneuroendocrinology, vol. 30, no. 2, pp. 188–198, 2005. View at Publisher · View at Google Scholar · View at Scopus
  32. S. Melmed and D. Kleinberg, Williams Textbook of Endocrinology, Saunders, 10th edition, 2003.
  33. C. Heim, U. M. Nater, E. Maloney, R. Boneva, J. F. Jones, and W. C. Reeves, “Childhood trauma and risk for chronic fatigue syndrome Association with Neuroendocrine Dysfunction,” Archives of General Psychiatry, vol. 66, no. 1, pp. 72–80, 2009. View at Publisher · View at Google Scholar · View at Scopus
  34. U. M. Nater, E. Maloney, R. S. Boneva et al., “Attenuated morning salivary cortisol concentrations in a population-based study of persons with chronic fatigue syndrome and well controls,” Journal of Clinical Endocrinology and Metabolism, vol. 93, no. 3, pp. 703–709, 2008. View at Publisher · View at Google Scholar · View at Scopus
  35. S. Gupta, E. Aslakson, B. M. Gurbaxani, and S. D. Vernon, “Inclusion of the glucocorticoid receptor in a hypothalamic pituitary adrenal axis model reveals bistability,” Theoretical Biology and Medical Modelling, vol. 4, article 8, 2007. View at Publisher · View at Google Scholar · View at Scopus
  36. J. Gaab, D. Hüster, R. Peisen et al., “Low-dose dexamethasone suppression test in chronic fatigue syndrome and health,” Psychosomatic Medicine, vol. 64, no. 2, pp. 311–318, 2002. View at Scopus
  37. F. Van Den Eede, G. Moorkens, B. Van Houdenhove, P. Cosyns, and S. J. Claes, “Hypothalamic-pituitary-adrenal axis function in chronic fatigue syndrome,” Neuropsychobiology, vol. 55, no. 2, pp. 112–120, 2007. View at Publisher · View at Google Scholar · View at Scopus
  38. W. K. Jerjes, N. F. Taylor, P. J. Wood, and A. J. Cleare, “Enhanced feedback sensitivity to prednisolone in chronic fatigue syndrome,” Psychoneuroendocrinology, vol. 32, no. 2, pp. 192–198, 2007. View at Publisher · View at Google Scholar · View at Scopus
  39. J. C. Ritchie, B. M. Belkin, K. Ranga, R. R. Krishnan, C. B. Nemeroff, and B. J. Carroll, “Plasma dexamethasone concentrations and the dexamethasone suppression test,” Biological Psychiatry, vol. 27, no. 2, pp. 159–173, 1990. View at Publisher · View at Google Scholar · View at Scopus
  40. T. Turan, H. B. Izgi, S. Ozsoy et al., “The effects of galantamine hydrobromide treatment on dehydroepiandrosterone sulfate and cortisol levels in patients with chronic fatigue syndrome,” Psychiatry Investigation, vol. 6, no. 3, pp. 204–210, 2009. View at Publisher · View at Google Scholar · View at Scopus
  41. A. J. Cleare, V. O'Keane, and J. P. Miell, “Levels of DHEA and DHEAS and responses to CRH stimulation and hydrocortisone treatment in chronic fatigue syndrome,” Psychoneuroendocrinology, vol. 29, no. 6, pp. 724–732, 2004. View at Publisher · View at Google Scholar · View at Scopus
  42. P. B. Himmel and T. M. Seligman, “A pilot study employing Dehydroepiandrosterone (DHEA) in the treatment of chronic fatigue syndrome,” Journal of Clinical Rheumatology, vol. 5, no. 2, pp. 56–59, 1999. View at Scopus
  43. M. Maes, I. Mihaylova, and M. De Ruyter, “Decreased dehydroepiandrosterone sulfate but normal insulin-like growth factor in chronic fatigue syndrome (CFS): relevance for the inflammatory response in CFS,” Neuroendocrinology Letters, vol. 26, no. 5, pp. 487–492, 2005. View at Scopus
  44. L. V. Scott, F. Svec, and T. Dinan, “A preliminary study of dehydroepiandrosterone response to low-dose ACTH in chronic fatigue syndrome and in healthy subjects,” Psychiatry Research, vol. 97, no. 1, pp. 21–28, 2000. View at Publisher · View at Google Scholar · View at Scopus
  45. F. Albright, K. Light, A. Light, L. Bateman, and L. A. Cannon-Albright, “Evidence for a heritable predisposition to chronic fatigue syndrome,” BMC Neurology, vol. 11, article 62, 2011. View at Publisher · View at Google Scholar · View at Scopus
  46. S. Kempke, P. Luyten, S. Claes et al., “The prevalence and impact of early childhood trauma in Chronic Fatigue Syndrome,” Of Psychiatric Research, vol. 47, no. 5, pp. 664–669, 2013. View at Publisher · View at Google Scholar
  47. F. Van Den Eede, T. Haccuria, M. De Venter, and G. Moorkens, “Childhood sexual abuse and chronic fatigue syndrome,” British Journal of Psychiatry, vol. 200, no. 2, pp. 164–165, 2012. View at Publisher · View at Google Scholar · View at Scopus
  48. C. Heim, D. Wagner, E. Maloney et al., “Early adverse experience and risk for chronic fatigue syndrome: results from a population-based study,” Archives of General Psychiatry, vol. 63, no. 11, pp. 1258–1266, 2006. View at Scopus
  49. J. D. Coplan, M. W. Andrews, L. A. Rosenblum et al., “Persistent elevations of cerebrospinal fluid concentrations of corticotropin-releasing factor in adult nonhuman primates exposed to early-life stressors: implications for the pathophysiology of mood and anxiety disorders,” Proceedings of the National Academy of Sciences of the United States of America, vol. 93, no. 4, pp. 1619–1623, 1996. View at Scopus
  50. I. C. G. Weaver, “Epigenetic programming by maternal behavior and pharmacological intervention—nature versus nurture: let's call the whole thing off,” Epigenetics, vol. 2, no. 1, pp. 22–28, 2007. View at Scopus
  51. I. C. G. Weaver, N. Cervoni, F. A. Champagne et al., “Epigenetic programming by maternal behavior,” Nature Neuroscience, vol. 7, no. 8, pp. 847–854, 2004. View at Publisher · View at Google Scholar · View at Scopus
  52. T. F. Oberlander, J. Weinberg, M. Papsdorf, R. Grunau, S. Misri, and A. M. Devlin, “Prenatal exposure to maternal depression, neonatal methylation of human glucocorticoid receptor gene (NR3C1) and infant cortisol stress responses,” Epigenetics, vol. 3, no. 2, pp. 97–106, 2008. View at Scopus
  53. K. M. Radtke, M. Ruf, H. M. Gunter et al., “Transgenerational impact of intimate partner violence on methylation in the promoter of the glucocorticoid receptor,” Translational Psychiatry, vol. 1, article e21, 2011. View at Publisher · View at Google Scholar · View at Scopus
  54. P. O. McGowan, A. Sasaki, A. C. D'Alessio et al., “Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse,” Nature Neuroscience, vol. 12, no. 3, pp. 342–348, 2009. View at Publisher · View at Google Scholar · View at Scopus
  55. N. Perroud, A. Dayer, C. Piguet et al., “Childhood maltreatment and methylation of the glucocorticoid receptor gene NR3C1 in bipolar disorder,” British Journal of Psychiatry, 2013. View at Publisher · View at Google Scholar
  56. N. Perroud, A. Paoloni-Giacobino, P. Prada et al., “Increased methylation of glucocorticoid receptor gene (NR3C1) in adults with a history of childhood maltreatment: a link with the severity and type of trauma,” Translational Psychiatry, vol. 1, article e59, 2011. View at Publisher · View at Google Scholar · View at Scopus
  57. P. O. McGowan, M. Suderman, A. Sasaki et al., “Broad epigenetic signature of maternal care in the brain of adult rats,” PLoS ONE, vol. 6, no. 2, Article ID e14739, 2011. View at Publisher · View at Google Scholar · View at Scopus
  58. B. Labonté, M. Suderman, G. Maussion et al., “Genome-wide epigenetic regulation by early-life trauma,” Archives of General Psychiatry, vol. 69, no. 7, pp. 722–731, 2012. View at Publisher · View at Google Scholar
  59. D. Collip, I. Myin-Germeys, M. Wichers et al., “FKBP5 as a possible moderator of the psychosis-inducing effects of childhood trauma,” British Journal of Psychiatry, vol. 202, no. 5, pp. 261–268, 2013. View at Publisher · View at Google Scholar
  60. W. B. Pratt and D. O. Toft, “Steroid receptor interactions with heat shock protein and immunophilin chaperones,” Endocrine Reviews, vol. 18, no. 3, pp. 306–360, 1997. View at Publisher · View at Google Scholar · View at Scopus
  61. T. Klengel, D. Mehta, C. Anacker et al., “Allele-specific FKBP5 DNA demethylation mediates gene-childhood trauma interactions,” Nature Neuroscience, vol. 16, no. 1, pp. 33–41, 2013. View at Publisher · View at Google Scholar
  62. M. H. Teicher, C. M. Anderson, and A. Polcari, “Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus,and subiculum,” Proceedings of the National Academy of Sciences of the United States of America, vol. 109, no. 9, pp. E563–E572, 2012. View at Publisher · View at Google Scholar · View at Scopus
  63. B. Grinde, “Is chronic fatigue syndrome caused by a rare brain infection of a common, normally benign virus?” Medical Hypotheses, vol. 71, no. 2, pp. 270–274, 2008. View at Publisher · View at Google Scholar · View at Scopus
  64. B. S. McEwen, “Seminars in medicine of the Beth Israel Deaconess Medical Center: protective and damaging effects of stress mediators,” New England Journal of Medicine, vol. 338, no. 3, pp. 171–179, 1998. View at Publisher · View at Google Scholar · View at Scopus
  65. S. B. Harvey, M. Wadsworth, S. Wessely, and M. Hotopf, “The relationship between prior psychiatric disorder and chronic fatigue: evidence from a national birth cohort study,” Psychological Medicine, vol. 38, no. 7, pp. 933–940, 2008. View at Publisher · View at Google Scholar · View at Scopus
  66. E. Fries, “Hypocortisolemic disorders,” in Stress: The Brain-Body Connection. Key Issues in Mental Health, D. H. Hellhammer and J. Hellhammer, Eds., vol. 174, pp. 60–77, 2008. View at Publisher · View at Google Scholar
  67. V. O'Keane, T. Frodl, and T. G. Dinan, “A review of atypical depression in relation to the course of depression and changes in HPA axis organization,” Psychoneuroendocrinology, vol. 37, no. 10, pp. 1589–1599, 2012. View at Publisher · View at Google Scholar · View at Scopus
  68. L. V. Scott and T. G. Dinan, “Vasopressin and the regulation of hypothalamic-pituitary-adrenal axis function: implications for the pathophysiology of depression,” Life Sciences, vol. 62, no. 22, pp. 1985–1998, 1998. View at Publisher · View at Google Scholar · View at Scopus
  69. A. P. Harris, M. C. Holmes, E. R. de Kloet, K. E. Chapman, and J. R. Seckl, “Mineralocorticoid and glucocorticoid receptor balance in control of HPA axis and behaviour,” Psychoneuroendocrinology, vol. 38, no. 5, pp. 648–658, 2013. View at Publisher · View at Google Scholar
  70. E. R. De Kloet, E. Vreugdenhil, M. S. Oitzl, and M. Joëls, “Brain corticosteroid receptor balance in health and disease,” Endocrine Reviews, vol. 19, no. 3, pp. 269–301, 1998. View at Scopus
  71. M. V. Flinn, “Evolution and ontogeny of stress response to social challenges in the human child,” Developmental Review, vol. 26, no. 2, pp. 138–174, 2006. View at Publisher · View at Google Scholar · View at Scopus
  72. D. K. Surapaneni, Adapa SRSS, K. Preeti, G. R. Teja, M. Veeraragavan, and S. Krishnamurthy, “Shilajit attenuates behavioral symptoms of chronic fatigue syndrome by modulating the hypothalamic-pituitary-adrenal axis and mitochondrial bioenergetics in rats,” Journal of Ethnopharmacology, vol. 143, no. 1, pp. 91–99, 2012. View at Publisher · View at Google Scholar
  73. C. L. Raison and A. H. Miller, “Malaise, melancholia and madness: the evolutionary legacy of an inflammatory bias,” Brain, Behavior and Immunity, vol. 31, pp. 1–8, 2013. View at Publisher · View at Google Scholar
  74. F. Martinon, A. Mayor, and J. Tschopp, “The inflammasomes: guardians of the body,” Annual Review of Immunology, vol. 27, pp. 229–265, 2009. View at Publisher · View at Google Scholar · View at Scopus
  75. M. ter Wolbeek, L. J. P. van Doornen, A. Kavelaars, E. M. van de Putte, M. Schedlowski, and C. J. Heijnen, “Longitudinal analysis of pro- and anti-inflammatory cytokine production in severely fatigued adolescents,” Brain, Behavior, and Immunity, vol. 21, no. 8, pp. 1063–1074, 2007. View at Publisher · View at Google Scholar · View at Scopus
  76. G. E. Miller, E. Chen, J. Sze et al., “A functional genomic fingerprint of chronic stress in humans: blunted glucocorticoid and increased NF-κB signaling,” Biological Psychiatry, vol. 64, no. 4, pp. 266–272, 2008. View at Publisher · View at Google Scholar · View at Scopus
  77. A. V. Turnbull and C. L. Rivier, “Regulation of the hypothalamic-pituitary-adrenal axis by cytokines: actions and mechanisms of action,” Physiological Reviews, vol. 79, no. 1, pp. 1–71, 1999. View at Scopus
  78. B. Van Houdenhove and P. Luyten, “Customizing treatment of chronic fatigue syndrome and fibromyalgia: the role of perpetuating factors,” Psychosomatics, vol. 49, no. 6, pp. 470–477, 2008. View at Publisher · View at Google Scholar · View at Scopus
  79. L. Lewis, J. Pairman, G. Spickett, and J. Newton, “Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome,” Journal of Internal Medicine, vol. 273, no. 5, pp. 501–510, 2013. View at Publisher · View at Google Scholar
  80. A. Hoad, G. Spickett, J. Elliott, and J. Newton, “Postural orthostatic tachycardia syndrome is an under-recognized condition in chronic fatigue syndrome,” QJM, vol. 101, no. 12, pp. 961–965, 2008. View at Publisher · View at Google Scholar · View at Scopus
  81. J. F. Thayer and E. Sternberg, “Beyond heart rate variability: vagal regulation of allostatic systems,” Annals of the New York Academy of Sciences, vol. 1088, pp. 361–372, 2006. View at Publisher · View at Google Scholar · View at Scopus
  82. A. D. L. Roberts, S. Wessely, T. Chalder, A. Papadopoulos, and A. J. Cleare, “Salivary cortisol response to awakening in chronic fatigue syndrome,” British Journal of Psychiatry, vol. 184, pp. 136–141, 2004. View at Publisher · View at Google Scholar · View at Scopus
  83. J. Bearn and S. Wessely, “Neurobiological aspects of the chronic fatigue syndrome,” European Journal of Clinical Investigation, vol. 24, no. 2, pp. 79–90, 1994. View at Scopus
  84. L. Jason, K. Muldowney, and S. Torres-Harding, “The Energy Envelope Theory and myalgic encephalomyelitis/chronic fatigue syndrome,” AAOHN Journal, vol. 56, no. 5, pp. 189–195, 2008. View at Publisher · View at Google Scholar · View at Scopus
  85. J. C. Van Denderen, J. W. Boersma, P. Zeinstra, A. P. Hollander, and B. R. Van Neerbos, “Physiological effects of exhaustive physical exercise in primary fibromyalgia syndrome (PFS): is PFS a disorder of neuroendocrine reactivity?” Scandinavian Journal of Rheumatology, vol. 21, no. 1, pp. 35–37, 1992. View at Scopus
  86. J. K. Prague, S. May, and B. C. Whitelaw, “Cushing's syndrome,” BMJ, vol. 346, article f945, 2013. View at Publisher · View at Google Scholar
  87. S. B. Sarkar, S. Sarkar, S. Ghosh, and S. Bandyopadhyay, “Addison's disease,” Contemporary Clinical Dentistry, vol. 3, no. 4, pp. 484–486, 2012.
  88. A. J. Cleare, “The HPA axis and the genesis of chronic fatigue syndrome,” Trends in Endocrinology and Metabolism, vol. 15, no. 2, pp. 55–59, 2004. View at Publisher · View at Google Scholar · View at Scopus
  89. R. Moss-Morris, C. Sharon, R. Tobin, and J. C. Baldi, “A randomized controlled graded exercise trial for chronic fatigue syndrome: outcomes and mechanisms of change,” Journal of Health Psychology, vol. 10, no. 2, pp. 245–259, 2005. View at Publisher · View at Google Scholar · View at Scopus
  90. J. B. Prins, J. W. M. Van Der Meer, and G. Bleijenberg, “Chronic fatigue syndrome,” Lancet, vol. 367, no. 9507, pp. 346–355, 2006. View at Publisher · View at Google Scholar · View at Scopus
  91. P. Whiting, A. M. Bagnall, A. J. Sowden, J. E. Cornell, C. D. Mulrow, and G. Ramírez, “Interventions for the treatment and management of chronic fatigue syndrome: a systematic review,” Journal of the American Medical Association, vol. 286, no. 11, pp. 1360–1368, 2001. View at Scopus
  92. M. P. Davis, D. Khoshknabi, and G. H. Yue, “Management of fatigue in cancer patients,” Current Pain and Headache Reports, vol. 10, no. 4, pp. 260–269, 2006. View at Publisher · View at Google Scholar · View at Scopus
  93. P. J. Goodnick and R. Sandoval, “Psychotropic treatment of chronic fatigue syndrome and related disorders,” Journal of Clinical Psychiatry, vol. 54, no. 1, pp. 13–20, 1993. View at Scopus
  94. J. Gaab, D. Hüster, R. Peisen et al., “Hypothalamic-pituitary-adrenal axis reactivity in chronic fatigue syndrome and health under psychological, physiological, and pharmacological stimulation,” Psychosomatic Medicine, vol. 64, no. 6, pp. 951–962, 2002. View at Publisher · View at Google Scholar · View at Scopus
  95. B. H. Natelson, J. Cheu, N. Hill et al., “Single-blind, placebo phase-in trial of two escalating doses of selegiline in the chronic fatigue syndrome,” Neuropsychobiology, vol. 37, no. 3, pp. 150–154, 1998. View at Publisher · View at Google Scholar · View at Scopus
  96. R. McKenzie, A. O'Fallon, J. Dale et al., “Low-dose hydrocortisone for treatment of chronic fatigue syndrome: a randomized controlled trial,” Journal of the American Medical Association, vol. 280, no. 12, pp. 1061–1066, 1998. View at Publisher · View at Google Scholar · View at Scopus
  97. A. J. Cleare, J. Miell, E. Heap et al., “Hypothalamo-pituitary-adrenal axis dysfunction in chronic fatigue syndrome, and the effects of low-dose hydrocortisone therapy,” Journal of Clinical Endocrinology and Metabolism, vol. 86, no. 8, pp. 3545–3554, 2001. View at Publisher · View at Google Scholar · View at Scopus
  98. K. Holtorf, “Diagnosis and treatment of hypothalamic-pituitary-adrenal (HPA) axis dysfunction in patients with chronic fatigue syndrome (CFS) and fibromyalgia (FM),” Journal of Chronic Fatigue Syndrome, vol. 14, no. 3, pp. 59–88, 2008. View at Publisher · View at Google Scholar · View at Scopus
  99. A. L. Buchman, “Side effects of corticosteroid therapy,” Journal of Clinical Gastroenterology, vol. 33, no. 4, pp. 289–294, 2001. View at Publisher · View at Google Scholar · View at Scopus
  100. H. G. Kim, J. S. Lee, J. M. Han et al., “Myelophil attenuates brain axidative damage by modulating the hypothalamus-pituitary-adrenal (HPA) axis in a chronic cold-stress mouse model,” Journal of Ethnopharmacology, vol. 148, no. 2, pp. 505–515, 2013. View at Publisher · View at Google Scholar
  101. C. Krishna, “New research body to look at chronic fatigue syndrome,” BMJ, vol. 346, article f2630, 2013. View at Publisher · View at Google Scholar