Gulf War syndrome or Gulf War illness is a chronic and multi-symptomatic disorder affecting military veterans of both sides of the 1990–1991 Persian Gulf War. A wide range of acute and chronic symptoms have been linked to it, including fatigue, muscle pain, cognitive problems, insomnia, rashes and diarrhea. Approximately 250,000 of the 697,000 U.S. veterans who served in the 1991 Gulf War have enduring chronic multi-symptom illness, a condition with serious consequences. The Royal British Legion said research suggested up to 33,000 UK Gulf War veterans could be living with the syndrome, with 1,300 claiming a war pension for conditions connected to their service. In 2007 the Royal British Legion produced a comprehensive report entitled Legacy of Suspicion, which made recommendations about necessary research and compensation. The Royal British Legion is still campaigning for the UK government to properly address symptoms experienced by veterans of the Gulf War. From 1995 to 2005, the health of combat veterans worsened in comparison with nondeployed veterans, with the onset of more new chronic diseases, functional impairment, repeated clinic visits and hospitalizations, chronic fatigue syndrome-like illness, post-traumatic stress disorder, and greater persistence of adverse health incidents. Exposure to pesticides and exposure to pills containing pyridostigmine bromide (used as a pretreatment to protect against nerve agent effects) has been found to be associated with the neurological effects seen in Gulf War syndrome. Other causes that have been investigated are sarin, cyclosarin, and emissions from oil well fires, but their relationship to the illness is not as clear. Studies have consistently indicated that Gulf War syndrome is not the result of combat or other stressors and that Gulf War veterans have lower rates of post-traumatic stress disorder (PTSD) than veterans of other wars. According to a 2013 report by the Iraq and Afghanistan Veterans of America, veterans of the U.S. wars in Iraq and Afghanistan may also have Gulf War syndrome, though later findings identified causes that would not have been present in those wars. In 2022, researchers led by Robert Haley, MD at University of Texas Southwestern Medical Center found that exposure to sarin nerve gas in soldiers who had a particular genetic mutation that prevented them from breaking down the nerve gas is likely to be responsible for the syndrome. The findings and an editorial by two leading epidemiologists were published in Environmental Health Perspectives. From Wikipedia