Chronic Fatigue Syndrome (CFS) has remained a mystery for a long time, and in some ways it’s only deepening. It was once believed that the syndrome was caused by a virus – but this theory was recently discredited, leaving researchers to search for a new explanation.

Some are now interested in understanding the brains of people with CFS, and hoping to find some answers there. A new study has reported that there are some fundamental differences between people with and without CFS. Whether the findings will truly work to uncover more answers is still unclear.

the team found that people with CFS had less change in blood flow between winning and losing. What’s more, people with more severe CFS had even less change in blood flow.

The team had noticed that people who were treated with interferon for Hepatitis C often experienced extreme fatigue as a result. They also had less activity in an area of the brain called the basal ganglia, which is responsible for the perception of pleasure, and often referred to as the brain’s “reward center.” So they reasoned that similar brain changes might be going on in people with CFS, for whom fatigue is ever-present and pleasure is often elusive.

They had CFS patients and healthy people play a card game that involved a monetary reward for correct guesses. The participants’ brains were scanned while they were playing the game, so the team could compare any differences in activation.

When healthy people are rewarded, blood flow to the basal ganglia usually increases markedly. But the team found that people with CFS had less change in blood flow between winning and losing. What’s more, people with more severe CFS had even less change in blood flow.

"Many patients with chronic fatigue syndrome encounter a lot of skepticism about their illness," lead author Dr. Elizabeth Unger, chief of the chronic viral diseases branch of the U.S. Centers for Disease Control and Prevention, said in a news release. "They have difficulty getting their friends, colleagues, coworkers, and even some physicians to understand their illness. These results provide another clue into the biology of chronic fatigue syndrome."

The researchers aren’t quite sure why the brain changes exist as they do, but it may have something to do with increased inflammation, which is being linked to a growing list of serious health problems. More research will need to look into the possibilities, but the study presents at least a new avenue to explore in this enigmatic syndrome.

The study was carried out by researchers at the CDC and was presented at the Experimental Biology annual meeting in San Diego, CA.