Differential Diagnosis Between CFS/CFIDS/ME and Somatoform Disorders

There are a number of somatoform disorders. The most relevant, in terms of differential diagnosis with CFS/CFID/MES, are somatization disorder and "neurasthenia".

The DSM-IV criteria for somatization disorder require a history of many physical complaints beginning before the age of 30. Epidemiological research on CFS/CFIDS/ME demonstrates that the majority of CFIDS patients have an onset at an age above 30. "The onset of multiple physical symptoms later in life is almost always due to physical disease." (Massachusetts CFIDS/ME & FM Association Physician's Primer).  Fatigue, which is a major CFS/CFIDS/ME symptom is not a symptom of somatization disorder; nor is disordered sleep or decreased concentration. The only symptoms in common are head, joint, and possible muscle pain.

Neurasthenia, characterized by fatigue and weakness, is listed in DSM-IV as Undifferentiated Somatoform Disorder. Neurasthenia, a common diagnosis at the end of the 19^th century has generally fallen into disfavor. The DSM-IV definition is: "one or more physical complaints (e.g., fatigue, loss of appetite, gastrointestinal, or urinary complaints) for which either 1) the symptoms cannot be fully explained by a known general medical condition, or 2) when there is a medical condition, the physical complaints are excessive in relation to the condition."

The definition of "neurasthenia" is obviously vague—it requires an interpretation that physical symptoms are either "excessive" or "unexplained". Specialists familiar with the symptomatology, pathophysiology, epidemiology, and the extensive research into metabolic dysregulation in CFS/CFIDS/ME would not be prone to making the psychiatric diagnosis.