Uncertainty About The Causes of Fibromyalgia

Many diseases and syndromes have a specific cause or a set of specific factors that have been clearly demonstrated through research to increase the risk of developing or contributing to the development of that disease or condition. In the case of fibromyalgia, there is a long list of possible related factors or causes that may increase the likelihood of developing the syndrome, but there is no absolute connection.

There are several different reasons why the causes of fibromyalgia remain somewhat elusive by medical standards. One major factor is the concurrent conditions that are often diagnosed with fibromyalgia, or prior to the diagnosis of fibromyalgia, that may have the same sets of factors or may create the same triggers. For example, there is a high correlation of fibromyalgia in women, particularly menopausal and post-menopausal women, who are also diagnosed with depression.

Researchers have yet to determine if there is a neurological connection that causes the physical pain often experienced in depression with the physical pain that is a key symptom in the diagnosis of fibromyalgia. It is also, at least at this point, impossible for researchers to determine which condition was actually present first. Was it the fibromyalgia that resulted in the depression, or was it the depression that triggered the onset of fibromyalgia.

In a Canadian study of 1,635 individuals diagnosed with fibromyalgia syndrome it was found that a diagnosis of depression was three times more likely in those with fibromyalgia than in the same age population without fibromyalgia. Within this study 22% of the fibromyalgia group was identified as having major depression. Of this group 2/5 had not discussed their mental health status with their primary care physician or a mental health professional within the proceeding year from the date of the survey. 1

The Stress Factor

Another complicating factor in determining the specific causes of fibromyalgia is the role that stress plays in the development of the syndrome. Again, fibromyalgia is often found with more commonly diagnosed and recognized stress related conditions such as Irritable Bowel Syndrome (IBS), chronic fatigue syndrome, posttraumatic stress disorder (PTSD) and even with stress related depression.

A leading factor in the ability of the body to regulate stress hormones is the HPA or hypothalamic-pituitary-adrenal axis. Some researchers believe that excessive levels of stress lead to a condition known as adrenal fatigue, where the body does not produce the correct levels of hormones within the HPA. Yet other studies seem to indicate that the hippocampus, which regulates sleep and pain perceptions may be the cause of the imbalances in the body that creates the environment for fibromyalgia to occur.

Some research has linked alternations in the CNS or central nervous system to the development of the symptoms of fibromyalgia when stress is present. This includes changes in the chemicals, physiology and even anatomy of various parts of the brain. In brain imagining studies, changes in pain-related brain activity are clearly visible, and tests also verify people with fibromyalgia have abnormalities in the dopaminergic, opioidergic, and serotoninergic systems. These systems control the chemicals in the brain that regulate pain perception, and the ability of the body to ignore pain, as well as sleep patterns. These systems are functioning at a lower level than seen in individuals without fibromyalgia. 2

However, the major drawback in using this as a definitive cause is that not all people who are stressed exhibit these changes. In the research just mentioned the researchers indicated that fibromyalgia may be a secondary disorder, not a primary disorder, that occurs only after prolonged stress, early life stress and when the individuals are genetically susceptible. 2

The Genetic Factor 

There is evidence that the cause or a contributing factor to the development of fibromyalgia may be genetic. This is based on the findings that fibromyalgia is most commonly found in people with neuroendocrine imbalances or disturbances in autonomic functioning. The genetic factors indicated are most likely associated with polymorphisms in the serotoninergic, dopaminergic and catecholaminergic systems, which are the brain chemical control systems. A polymorphism occurs when a gene mutates to create an unusual or atypical genetic expression. In addition, the research hypothesizes that the inheritance of the genetic polymorphisms is polygenic, which means there is an inheritance of multiple genes, not just one gene. 3

In research there is also a strong indication that the genetic factors alone, the specific polymorphisms, do not necessarily cause fibromyalgia unless the environmental factors that lead to stress are present. This is similar to the other stress related conditions including IBS, PTSD and chronic fatigue syndrome. Research also seems to indicate that it is the age and stage of life that the stress occurs combined with duration of the stress that is a major causal factor in a diagnosis of fibromyalgia. Later in life the presence of other health issues including depression or chronic diseases like diabetes is more likely.

Since there is not a universally accepted framework for diagnosis of fibromyalgia, there is some concern that there may be a vast number of people that are not diagnosed and therefore not included in studies and clinical trials. In addition the rate at which fibromyalgia is diagnosed with other mental and physical health conditions further complicates the identification of clear causes of the syndrome.

As research advances and is able to more accurately image the human brain and study the specific polymorphisms and changes in brain chemistry, hormonal production and metabolism, there is increased likelihood that the specific factors or causes of fibromyalgia will be identified.

Finding the specific causes of fibromyalgia may be instrumental in finding a way to cure, not just control and manage the symptoms. This would be of great benefit to those with the syndrome and would also provide a way to identify high risk groups or populations that could be educated and trained in prevention of fibromyalgia.

References

1 Fuller-Thmoson, E., Nimigon-Young, J., & Brennenstuhl, S. (2011). Individuals with fibromyalgia and depression: Findings from a nationally representative Canadian survey. Rheumatology International .

2 Schweinhardt, P., Sauro, K., & Bushnell, M. (2008). Fibromyalgia: A Disorder of the Brain? The Neuroscientist , 415-421.

3 Buskila, D., Sarzi-Puttini, P., & Ablin, J. (2007). The Genetics of Fibromyalgia Syndrome. Pharmacogenomics , 67-74.

This article was originally published on July 11, 2012 and last revision and update of it was 9/7/2015