Until recently, researchers were very much in the dark about chronic fatigue syndrome causes. Doctors tried blood tests and brain scans to detect patterns in patients, but the Center for Disease Control said the only way to really diagnose a patient was to see if they had 4 out of the 8 symptoms of CFS that persisted for more than six months. Related symptoms include fatigue, exhaustion long after exercise or exertion, cognitive impairments, headaches, sore throat, joint pain, muscle aches and tiredness even after sufficient sleep.

Are the causes of chronic fatigue syndrome physical or mental? This subject plagues every CFS patient who feels misunderstood by his or her peers. One aspect of the problem is the lack of medical tests to diagnose this condition. Diagnosis of the syndrome normally consists of eliminating every other possible cause, which leads some to speculate that the condition isn’t genuine. One thing that is acknowledged is that CFS patients experience profound exhaustion and aggravation of other problems following even mild physical activity. Through clinical investigation, it is hoped that researchers can answer some vital questions concerning CFS. Only recently, new links have been revealed to shed some light on this baffling condition.

In the past, the causes of CFS were assumed to have a genetic link. Scientists saw that there were genes involved in the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system that were modified. These genes control a person’s reaction to trauma, injury and other stressful situations, therefore the abnormalities discovered could have conceivably had an effect on cellular energy transfer, immune system function and cell communication. Individuals with CFS have a number of gene differences, yet there hasn’t been just one gene recognized as responsible for the medical symptoms associated with chronic fatigue syndrome.

Another one of the proposed chronic fatigue syndrome causes has to do with abnormalities of the central nervous system and hormones. Abnormal chemical levels in the hypothalamus-pituitary-adrenal axis may be one cause of chronic fatigue medical symptoms, scientists have posited. For instance, some patients with CFS have abnormally high levels of seratonin (a chemical messenger in the brain) and abnormally low levels of dopamine (a neurotransmitter associated with sleep and feelings of reward). In other cases, CFS patients have imbalances between norepinephrine and dopamine levels or lower levels of the stress hormone cortisol. Fatigue can also be caused by a disturbed sleep-wake cycle, researchers add.

In October 2009, a team of researchers from the University of Nevada at Reno and the National Cancer Institute reported a definitive link between chronic fatigue syndrome and a virus called XMRV, which appeared in the vast majority of CFS patients they studied. The XMRV chronic fatigue virus is one of just three known retroviruses; the other two being HIV and HTLV. All three viruses are transmitted through bodily fluids. However, scientists are, at this point, cautious to point to a virus as one of the predominant chronic fatigue syndrome causes. “There’s been a tremendous interest in chronic fatigue syndrome. I’ve been getting almost nonstop calls from doctors and patients,” explains one of the head researchers, Robert Silverman from the Lerner Research Institute. “They’re obviously looking for hope in this study, although the virus is not proven to cause CFS. That’s still unknown. But until it’s ruled out, it’s going to obviously be a subject of great interest.”