For many years physicians believed chronic fatigue syndrome (CFS) to be a complicated psychological disorder and not an actual biological one.  However, researchers have now found evidence that chronic fatigue syndrome is a result of immunological dysfunction, meaning that it is, in fact, a biological illness after all.

"We now have evidence confirming what millions of people with this disease already know, that CFS is not psychological," director of translational research at the Center for Infection and Immunity, Columbia University and lead author of the study, Mady Hornig says. "Our results should accelerate the process of establishing the diagnosis after individuals first fall ill as well as discovery of new treatment strategies focusing on these early blood markers."

For the study published in the journal Science Advances, researchers used immunoassay testing methods to find the levels of 51 immune biomarkers in blood plasma samples collected from 298 patients suffering from CFS along with 348 healthy controls.  The researchers were able to identify distinct immunological changes in patients diagnosed with chronic fatigue syndrome, known medically as myalgic encephalomyelitis.

Researchers found specific patterns in patients who had the disease for three years or less that were not present in the controls or in patients that had suffered from the disease for longer than three years.

People who had suffered from the disease for three years or less had increased amounts of many different types of immune molecules called cytokines.  The association was unusually strong with a cytokine known as "interferon gamma" that has been linked to fatigue during viral infections.

"This study delivers what has eluded us for so long: unequivocal evidence of immunological dysfunction in ME/CFS and diagnostic biomarkers for disease," senior author from Columbia University's Mailman School of Public Health, W. Ian Lipkin says.

This new evidence demonstrating that chronic fatigue syndrome is actually a biological condition and not psychological could alter how the disease is treated by physicians in the future. 

The CDC estimates that approximately 1 million Americans suffer from CFS with 80% of the cases undiagnosed.  The disorder is characterized by extreme fatigue that does not improve with rest and is often only made worse by physical or mental activity.  Symptoms may include weakness, muscle pain, impaired memory or mental concentration, and insomnia.

This new breakthrough could one day help researchers discover the true source of the disorder, and even help them create treatments for people suffering from chronic fatigue syndrome.