WASHINGTON, Oct. 14 - A federal panel of medical experts studying illnesses among veterans of the 1991 war in the Persian Gulf has broken with several earlier studies and concluded that many suffer from neurological damage caused by exposure to toxic chemicals, rejecting past findings that the ailments resulted mostly from wartime stress.
Citing new scientific research on the effects of exposure to low levels of neurotoxins, the Research Advisory Committee on Gulf War Veterans' Illnesses concludes in its draft report that "a substantial proportion of Gulf War veterans are ill with multisymptom conditions not explained by wartime stress or psychiatric illness."
It says a growing body of research suggests that many veterans' symptoms have a neurological cause and that there is a "probable link" to exposure to neurotoxins.
The report says possible sources include sarin, a nerve gas, from an Iraqi weapons depot blown up by American forces in 1991; a drug, pyridostigmine bromide, given to troops to protect against nerve gas; and pesticides used to protect soldiers in the region.
Dr. Joyce C. Lashof , the chairwoman of a presidential advisory group that reported in 1996 that there was no causal link between toxic exposure and the veterans' symptoms, said Thursday that she had not seen the new report. But Dr. Lashof said she was open to changing her views if the findings were based on solid new research and not advocacy by veterans' groups.
"We certainly weren't sure that our report was the definitive answer," Dr. Lashof, professor emerita of public health at the University of California at Berkeley, said. "It was based on the best evidence available at the time."
All the chemicals cited in the new study belong to a group called acetylcholinesterase inhibitors, which can cause a range of symptoms including pain, fatigue, diarrhea and cognitive impairment. Committee members said there might be minor changes in the report, a draft copy of which was obtained by The New York Times, but that the basic scientific findings would not change.
The committee says a search for medical treatments tailored to the new findings are "urgently needed" and recommends $60 million in federal funds for new research over the next four years. It says an estimated 100,000 Gulf War veterans, or about one in seven, suffer war-related health problems.
The report also says that understanding illnesses from the war will be critical in planning future military deployments and measures to improve domestic security. It calls for a reassessment of the use of pyridostigmine bromide.
Though some conclusions are hedged in careful language in the 135-page draft report, committee members said in interviews that they were consciously departing from the past scientific consensus and taking a strong stand on a politically and scientifically volatile subject.
"I would absolutely say it's a break from previous panels," said Dr. Beatrice A. Golomb, an associate professor of medicine at the University of California at San Diego, a member of the panel and its scientific director for much of its existence. "It reflects a different body of evidence, because more studies have come out. No one had gone to the scientific evidence on acetylcholinesterase inhibitors."
The new report, prepared for the federal Department of Veterans Affairs, draws conclusions that are essentially the opposite of those of the Presidential Advisory Committee on Gulf War Veterans' Illnesses, led by Dr. Lashof. That group reported to President Bill Clinton in 1996 that "current scientific evidence does not support a causal link" between the veterans' symptoms and chemical exposures in the Persian Gulf.
Instead, the earlier group said, stress "is likely to be an important contributing factor to the broad range of physical and psychological illnesses currently being reported by gulf war veterans."
Another panel of scientists convened in 1998 by the Institute of Medicine, a unit of the National Academies that focuses on health and medical advice, has produced a series of reports that generally point away from neurotoxin exposure as a likely cause of the veterans' illnesses.
Some 697,000 American troops were sent to the Persian Gulf at the end of 1990 to drive the Iraqi forces of President Saddam Hussein out of Kuwait. Though the military campaign was swift and successful, 13 years after the war ended many veterans still complain of persistent fatigue, headaches, joint pain, numbness, diarrhea and other health problems.
Among dozens of studies cited by the new report is a 1998 survey that looked at about 2,000 Kansas veterans, 1,548 of whom served in the gulf. It found that more than 30 percent of the gulf veterans report three or more such symptoms. The presence of multiple symptoms, their persistence for many years and the dominance of muscular and skeletal complaints all distinguish the ailments of gulf war veterans from the ailments of veterans of other wars, Dr. Golomb said.
The Pentagon admitted in 1997 that as many as 100,000 American service members might have been exposed to nerve gas when American combat engineers blew up the Kamisiyah ammunition depot in southern Iraq in March 1991, shortly after the war.
The new panel was appointed in 2002 by Anthony J. Principi, the veterans affairs secretary, in accordance with a law passed in 1998 but never acted on by the Clinton administration. Of the 11 members 7 are scientists and 4 are veterans, including the chairman, James Binns, a Vietnam veteran and former Pentagon official. Eight other scientists worked as advisers to the panel.
Committee members said release of the report, which was described in the Oct. 1 issue of Science magazine, had been set for earlier this month but was postponed because of scheduling problems.
Through a spokeswoman, Mr. Principi, who was in Michigan Thursday for the groundbreaking of a new veterans cemetery, praised the committee's work.
"I'm looking forward to studying the committee's report and working with them to ensure adequate research funding to find answers to these perplexing medical issues," he said. He said the department was already providing disability benefits for some veterans who have developed amyotrophic lateral sclerosis, or Lou Gehrig's disease, based on studies finding that the veterans have nearly double the risk of the disease as veterans who did not go to the Persian Gulf do.
According to his spokeswoman, Cynthia Church, Mr. Principi, a combat-decorated Navy veteran of the Vietnam War, took a particular interest in the research of Dr. Robert W. Haley, whom he appointed to the panel. Dr. Haley, chief of epidemiology at the University of Texas Southwestern Medical Center in Dallas, has written a series of studies of the possible effects of neurotoxins on gulf war veterans, including some financed by the Texas billionaire H. Ross Perot.
Dr. Haley acknowledged that his work, which has been championed by some veterans and members of Congress, has been viewed skeptically by some scientists. He said the current committee's findings represent a "revolutionary change" from the past, when what he called "radically conservative" scientists dismissed the neurotoxin thesis.
"I think this committee has honestly weighed all the evidence," he said. "Although it's not proven, the preponderance of the evidence supports a new explanation - brain cell damage, nervous system damage caused by chemical exposures."
Jim Reichert, a 41-year-old industrial equipment mechanic who lives in Columbia, Ill., said he was heartened to hear of the committee's conclusions.
Mr. Reichert said he had served as a Blackhawk helicopter crewman in the war. After his six months in the gulf region, he developed strange symptoms which have never gone away, he said. Fatigue forced him to give up hunting and fishing, he loses control of his hand muscles and drops tools on the job, and he suffers from chronic diarrhea and a recurring, blistering skin condition.
"If it was stress alone, it wouldn't have lasted this long," Mr. Reichert said. Referring to himself and other ailing veterans, he said: "We're not crazy. If I'm a little nuts, it's because I've been sick so long."