Researchers Find Biological Evidence of Gulf War Illnesses In the two decades since the 1991 Persian Gulf war, medical researchers have struggled to explain a mysterious amalgam of problems in thousands of gulf war veterans, including joint pain, physical malaise and gastrointestinal disorders. In some medical circles, the symptoms were thought to be psychological, the result of combat stress. But recent research is bolstering the view that the symptoms, known collectively as gulf war illness, are fundamentally biological in nature. In the latest example, researchers at Georgetown University say they have found neurological damage in gulf war veterans reporting symptoms of the disease. Using magnetic resonance imaging to study the brains of gulf war veterans before and after exercise, the researchers discovered evidence of damage in parts of their brains associated with heart rate and pain. Such damage was not evident in the control group, which included nonveterans and healthy veterans. Such neurological damage, the researchers theorize, caused the veterans to be more sensitive to pain, to feel easily fatigued and to experience loss of short-term "working memory," all symptoms associated with gulf war illness. Their study, published by the online medical journal PLoS One on Friday, does not try to explain the causes of the damage. It also found different patterns of damage in two groups of veterans, indicating that the disease - if it is indeed a single ailment - takes different paths in different people. But the authors said the findings, along with other recent research, may offer clues in developing treatments and diagnostic tests for the illness, which currently is diagnosed through self-reported symptoms and has no definitive treatment. Two other studies released by Georgetown this year have also pointed to neurological damage in the brains of veterans reporting symptoms of gulf war illness, including one that showed abnormalities in the nerve cells linking parts of the brain involved in processing feelings of pain and fatigue. The research makes clear that "gulf war illness is real," said Rakib U. Rayhan, the principal author of the new study. There is objective evidence that something is wrong in the brains of these veterans. Other experts offered more tempered views, noting that most of the subjects in the Georgetown study were self-selected and that their number was relatively small: 28 veterans and 10 nonveterans. Dr. Drew A. Helmer, director of the Department of Veterans Affairs" War-Related Illness and Injury Study Center in New Jersey, called the Georgetown studies "very preliminary" but also "a very important step forward." But Dr. John Bailar, an emeritus professor at the University of Chicago who led a group that studied gulf war illness in 1996, said the new study did not provide enough data to determine whether the veterans" symptoms were linked to their deployments to Kuwait, or something entirely different. "I am not questioning whether a substantial proportion of veterans of Desert Storm have symptoms related to their service," Dr. Bailar said in an e-mail. I am questioning whether those symptoms have any cause other than the stress of war itself. Studies by the Department of Veterans Affairs have estimated that as many as 250,000 of the nearly 700,000 service members who served in the Middle East in 1990 and 1991 have reported symptoms of gulf war illness, which is also known as chronic multisymptom illness. Gulf war illness has been the source of much frustration and dispute practically since veterans first reported symptoms in the 1990s. Many veterans say that their complaints were initially dismissed as psychological. Many also believe that their problems are the result of exposure to nerve agents, pesticides, herbicides and other chemicals, but that the government has been slow, or unwilling, to pinpoint causes. Even some government researchers have made that case. At a Congressional hearing in March, Dr. Steven S. Coughlin, an epidemiologist who once worked for the Department of Veterans Affairs, asserted that the department had systematically played down the neurological basis of gulf war illness. At the same hearing, a member of an advisory panel to the department said the agency still seemed guided by the view that symptoms of gulf war illness were stress-induced. "This is a throwback to early speculation from the 1990s that there was no problem, or that veterans just had random, disconnected symptoms," testified Dr. Lea Steele, a Baylor University epidemiologist who was a member of the Research Advisory Committee on Gulf War Veterans" Illnesses.