The diagnosis of ME/CFS is sometimes complicated by co-existing conditions such as fibromyalgia, multiple chemical sensitivity, irritable bowel syndrome, migraines, allergies and depression. They may develop 'in the setting of ME/CFS' (e.g. multiple chemical sensitivity) or pre-date it but then 'become associated with it'.
ME/CFS and fibromyalgia are often closely connected and it is suggested they should be considered as overlapping conditions.
There are key differences between ME/CFS and fibromyalgia: ME/CFS is commonly initiated by a viral infection and fibromyalgia by physical trauma. In fibromyalgia pain is the major symptom - in ME/CFS it is fatigue and post-exertional malaise. Aerobic exercise will exacerbate symptoms in people with ME/CFS whereas people with mild fibromyalgia may be able to tolerate it better.
The disability experienced by people with ME/CFS is often aggravated when fibromyalgia and chemical sensitivity are also present.
Busch AJ et al., (2008) 'Exercise for Fibromyalgia: A Systematic Review' Journal of Rheumatology, vol. 35, no. 6, pp. 1130-1144.
Research has provided clear evidence that ME/CFS is not the same as depression or any other psychiatric disorder and no antidepressant has been shown to improve the core symptoms of ME/CFS. (4)
Depression can co-exist with ME/CFS but the incidence of depression with CFS is no higher than in people with other chronic illnesses. (5) There have been cases where people with ME/CFS have been wrongly diagnosed with major depression leading to inappropriate treatment.
The essential characteristics for a diagnosis of depression are a persistent, low or irritable mood and loss of pleasure and guilt or self blame whereas the essential symptoms of ME/CFS are severe, prolonged fatigue, post-exertional malaise, sleep dysfunction, pain, neurological/cognitive, autonomic, neuroendocrine and immune manifestations. (4)
Some of the clinical differences between depression and ME/CFS are tabulated below:
Differentiating ME/CFS and depression: Clinical presentation
|Infectious onset in over 80% of cases||Rarely follows infectious illness|
|Fatigue is necessary for diagnosis
||Mood change is necessary for diagnosis
|Muscle and/or joint pain and significant headaches
||Not usually associated with pain symptoms
|Diurnal variation with PM the worst time of the day
||Diurnal variation with the AM the worst time of the day
|Orthostatic intolerance, tachycardia and other autonomic dysfunctions are common
||No association with autonomic symptoms
|Immune manifestations including tender lymph nodes, sore throat, chemical and food sensitivities
||No association with immune symptoms
|Loss of body thermostatic stability, intolerance to extremes of temperature, fatigue worsened by physical or mental exertion
||No association with thermostatic instability
|Fatigue worsened by physical or mental exertion
||Fatigue and mood improve with exercise
|Decreased positive affect (energy, enthusiasm, happiness)
||Increased negative affect (apathy, hopelessness, suicide ideation, self reproach)
|Children have a better prognosis than adults
||Children have a worse prognosis than adults|
Adapted from Stein E, (2005) 'Assessment and Treatment of Patients with ME/CFS: Clinical Guidelines for Psychiatrists'.
There are also physiological differences between ME/CFS and depression, including raised urinary cortisol excretion with depression.
A sub-set of people with ME/CFS develop reactive, situational depression secondary to the loss of their health and previous lifestyle. 'It is important to discern whether the patient has ME/CFS, a psychiatric condition or both. Using the Canadian Criteria, the signs and symptoms of ME/CFS can clearly be distinguished from psychiatric disorders in most cases' (Stein 205, p.19).
Dr Eleanor Stein (Psychiatrist and ME/CFS practitioner) summarises the evidence that ME/CFS is not a psychiatric or psychological disorder and addresses various issues concerning ME/CFS (such as anxiety and grief) from the psychiatrist's perspective in 'Assessment and Treatment of Patients with ME/CFS: Clinical Guidelines for Psychiatrists' (2005).
Could mitochondrial dysfunction be a differentiating marker between Chronic Fatigue Syndrome and Fibromyalgia?
Daily cytokine fluctuations, driven by leptin, are associated with fatigue severity in chronic fatigue syndrome: evidence of inflammatory pathology A small pilot study of 10
Did you know?
As many as 180,000 Australians are directly affected by ME/CFS
Research into ME/CFS is occuring across the globe. Follow the links below for research resources.
Support Organisations by State
ME/CFS Australia directs enquiries from members of the community about frontline support for people with ME/CFS to independently run state organisations.
Nutrition and ME/CFS: Download a PDF, available in the following languages: