The idea that depression is at the root of the symptoms of ME/CFS has been exploded in two interesting overviews.
The first, aptly titled “Don’t Assume It’s Depression”, was a systematic review of the scientific literature on ME/CFS and depression conducted by researchers at West Virginia University. Their initial premise was that – since “at least 1 million Americans have CFS… yet more than 80% go undiagnosed” – it is important for clinicians to clearly identify the condition and differentiate it from other conditions, such as depression, which can cause superficially similar symptoms. From the literature, they found a basket of indicators — from the clinical history, physical and mental examinations, and diagnostic arena — which could be useful. Crucially, they stress that a good history (taken by the examining physician) is more important than any available diagnostic test to diagnose ME/CFS and differentiate it from depression. The Table shows the key points of difference, including perhaps the clearest indicator: the fact that ME/CFS patients show frustration at their physical limitations, and generally do not have the usual depressive symptoms of lack of enjoyment of life, guilt and lack of motivation.
The second review (in Journal of the American Academy of Physician Assistants) described how biological abnormalities separate ME/CFS from depression, emphasising that while the conditions share certain symptoms, many others, such as sore throat, lymphadenopathy, arthralgias, myalgias and post-exertional fatigue, are not typical of psychiatric illness. In addition, the review outlines some of the evidence for physiological differences, with two of the most important being sleep (reduced REM sleep latency in depression versus reduced slow-wave deep sleep in ME/CFS), and hypothalamus and pituitary function (high circulating cortisol levels in depression versus low in ME/CFS, compared with controls).
a) A systematic review of chronic fatigue syndrome: don’t assume it’s depression. Griffith & Zarrouf. Prim Care Companion J Clin Psychiatry 2008; 10(2): 120-8.
b) How biological abnormalities separate CFS from depression. Erdman KM. Journal of the American Academy of Physician Assistants 2008 Mar; 21(3): 19-23.