More progress has been made toward understanding the physiological mechanisms that underline the illness and identifying possible treatments, according to a report released Monday by a congressionally-mandated panel of experts and veterans.
But on a sour note, its authors expressed deep concerns about a lack of research on other health problems and mortality among Gulf War veterans.
Veterans of the 1990-1991 Gulf War have complained for two decades that they are not receiving adequate care for symptoms caused by exposure to toxic chemicals, including pesticides, and a drug administered to protect soldiers against nerve gas.
But treatment research has increased significantly since 2008, and "early results provide encouraging signs that the treatment goals identified in the 2010 Institute of Medicine report are achievable," the Research Advisory Committee on Gulf War Veterans' Illnesses said.
In 2008, a landmark RAC report established that Gulf War illness was a real condition.
"Studies published since 2008 continue to support the conclusion that Gulf War illness is causally related to chemical exposures in the combat theater," said RAC scientific director Roberta White, chair of environmental health at the Boston University School of Public Health.
Symptoms can vary from person to person, but typically include some combination of widespread pain, headache, persistent problems with memory and thinking, fatigue, breathing problems, stomach and intestinal symptoms, and skin abnormalities.
Central nervous system dysfunction is a "critical element in the disorder," White said, while studies also continue to show that Gulf War illness is not associated with psychological stressors during the war.
Fresh evidence has also emerged suggesting that certain exposures may be linked to brain cancer in Gulf War veterans.
Studies show that those veterans most exposed to released nerve gas during the destruction of the Khamisiyah arms depot in Iraq have significantly elevated rates of death due to brain cancer.
Veterans exposed to the highest level of contaminants from oil well fires also have increased rates of brain cancer deaths, the report says.
The panel also cited a number of "promising" treatment studies, including those testing certain dietary supplements, intranasal insulin and continuous positive airway pressure to ease fatigue and pain and improve cognitive function.
Yet it said that "very little research" has been conducted to determine rates at which veterans have been affected by neurological diseases such as multiple sclerosis or Parkinson's disease, cancers and reproductive problems.