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Chronic Neuroimmune Diseases
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Last updated January 1, 2014

Differentiating Between CFIDS and Primary Depression

Attribution missing, 1995

Frequently, people with CFIDS are misdiagnosed as having clinical depression as their primary disorder. In fact, most current research indicates that, while depression is often present in CFIDS (accompanied by numerous other physical symptoms), it is a secondary, not a causative, condition. And while psychiatric consultation may be an appropriate recommendation for people with CFIDS, it should not be the primary or the only medical response. It seems to be overlooked by too many health professionals--and family members--that depression is a not-unexpected ailment associated with chronic illnesses.

What are the factors that contribute to the physician's difficulty in differentiating CFIDS from a primary depressive disorder?

Some of the symptoms of CFIDS also occur in depression:

  • Fatigue, a primary symptom of CFIDS, is also a primary symptom of depression.

  • Cognitive impairment is common to both diseases.


There are similarities between depression and CFIDS in presentation and diagnosis:

  • Often there is an absence of clinical and laboratory findings in both CFIDS and depression.

  • Both disorders are typically invisible, making the patient appear to be physically well.


Many patients with CFIDS do suffer from depression, making the diagnosis an easy first call.

  • The fact of having a severely debilitating chronic disease can in itself cause depression.

  • There is preliminary evidence that CFIDS can cause a swelling in the lining of the brain causing biochemical depression.

  • It is now an accepted fact that most chronic diseases are accompanied by some form of depression.


The way CFIDS has emerged on the medical scene and the way primary medicine works have added to the confusion:

  • CFIDS has been slow to gain medical attention as a distinct organic entity.

  • Depression has historically been the specialty of psychiatrists and consequently most general practice physicians are not experts in determining whether the depression they are seeing in a patient is a primary or secondary diagnosis. Also, some physicians, in the absence of concrete medical findings, assume that symptoms are "all in the head" and that therefore depression must be the diagnosis.

The confusion surrounding CFIDS and depression is a frustrating one for physicians and patients. For example: Often people diagnosed with depression as their primary symptom are not taken seriously in general medicine. This means that a person with CFIDS who is misdiagnosed with depression may not be taken seriously, leaving him/her angry and abandoned. The fact that general medical practitioners tend not to take depression seriously, whether it is related to CFIDS or not, is extremely dangerous, as depression is known to be one of the most lethal diseases in medicine. The rate of suicide in those diagnosed with severe clinical depression, regardless of the cause, can be as high as 15%. However, depression is also one of the most treatable diseases, as more than 85% of patients improved with treatment. Once a physician suspects depression as a cause of a patient's problems, s/he is less likely to identify the more subtle and mostly invisible symptoms that could help lead to the diagnosis of other diseases. For example, the presence of depression accompanied by pain, swollen lymph glands, sudden onset, neurological difficulties, etc., would point towards a specific diagnostic picture of CFIDS, not primary depressive disorder. Depression is also an early warning sign of many other illnesses, including cancer. The diagnosis of depression in general medicine often means that the person will not be treated by a primary care medical doctor, but will be referred out to a psychiatrist or psychologist. In doing this, the physician misses the opportunity to treat physical problems which may in fact be causing the depression. The better approach, when primary depressive disorder is not the absolute and clear diagnosis, would be to seek consultation in treating the depression to see if reducing the depression also reduces the accompanying physical symptoms. (However, since more and more "antidepressant" medications are being used for pain control and immune system moderation, the fact that such a drug works on physical symptoms does not automatically mean depression was the cause.)

The treatment for depression related to chronic diseases like CFIDS is often different from that for primary depressive disorder, because in CFIDS the immune and nervous systems are involved. For example, people with CFIDS who take anti-depressant medications for a variety of reasons (pain, immune modulation, and depression) often must take considerably lower doses of anti-depressants than those with primary depressive disorder. The following information should be helpful in this discussion.

Both CFIDS and primary depression have the following symptoms in common:

Symptoms of clinical depression:

  • lethargy, fatigue

  • sleep disorder

  • inability to function

  • memory loss, "foggy" brain, cognitive deficit, concentration problems

  • aches and pains

  • sadness, hopelessness

  • weight loss or gain

Symptoms of anxiety:

  • shortness of breath

  • dizziness

  • diarrhea

  • chest pains

  • panic attacks

  • numbness, tingling

  • nausea

CFIDS has the following symptoms NOT common to depression:

  • mild fever

  • sore throat

  • painful or swollen lymph nodes

  • unexplained generalized muscle weakness

  • muscle pain

  • migratory joint pain without swelling or redness

  • sudden onset (without situational cause)

  • neurological disturbances


The following are significant differences between primary depression and CFIDS:

Manifestations of Depression   Manifestation of CFIDS
Low motivation   High motivation
Exercise alleviates symptoms   Exercise worsens symptoms
Patient underestimates capabilities on cognitive tests   Patient overestimates capabilities on cognitive test
Memorization not impaired by brief interruption   Memorization significantly impaired by brief interruption
Performance on memorization test enhanced by cues   Memorization cues worthless

Note: individuals meeting the diagnostic criteria for fibromyalgia only do benefit from some exercise, while those individual meeting the diagnostic criteria for both CFS and FM experience severe exacerbation of symptoms after even mild exertion.




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