According to the IOM, "It is clear that a significant portion of the soldiers deployed to the Gulf War have experienced troubling constellations of symptoms that are difficult to categorize," said committee chair Stephen L. Hauser, professor and chair, department of neurology, University of California, San Francisco (UCSF). Unfortunately, symptoms that cannot be easily quantified are sometimes incorrectly dismissed as insignificant and receive inadequate attention and funding by the medical and scientific establishment. Veterans who continue to suffer from these symptoms deserve the very best that modern science and medicine can offer to speed the development of effective treatments, cures, and—we hope—prevention. Our report suggests a path forward to accomplish this goal, and we believe that through a concerted national effort and rigorous scientific input, answers can be found. Questions still exist regarding why certain veterans showed, and still show, medically unexplained symptoms while others did not, why symptoms are diverse in some and specific in others, and why combat exposure is not consistently linked to having or not having symptoms. The lack of data on veterans pre-deployment and immediate post-deployment health status and lack of measurement and monitoring of the various substances to which veterans may have been exposed make it difficult—and in many cases impossible—to reconstruct what happened to service members during their deployments nearly 20 years after the fact, the committee noted.
Comorbid illnesses
Gulf War veterans have been identified to have an increased risk of multiple sclerosis.A 2017 study by the U.S. Department of Veterans Affairs found that veterans possibly exposed to chemical warfare agents at Khamisiyah experienced different patterns of brain cancer mortality risk compared to the other groups, with veterans possibly exposed having a higher risk of brain cancer in the time period immediately following the Gulf War. Iraqi veterans
Although an understudied group, opposing Iraqi veterans of the Iraqi Army in the Gulf War also experienced acute and chronic symptoms associated with Gulf War syndrome. A 2011 study in the U.S Army Medical Department Journal reported Iraqi veterans of the Gulf War had a higher prevalence of somatic disorders as compared to Iraqi civilians, with risk greater in troops stationed in Kuwait.In comparison to Allied troops, health symptoms were similar amongst Iraqi veterans: 

* Zone 1 = In Kuwait, Zone 3 = 360 km from Kuwait. Causes
The United States Congress mandated the U.S. Department of Veterans Affairs contract with the National Academy of Sciences (NAS) to provide reports on Gulf War illnesses. Since 1998, the NASs Institute of Medicine (IOM) has authored ten such reports. In addition to the many physical and psychological issues involved in any war zone deployment, Gulf War veterans were exposed to a unique mix of hazards not previously experienced during wartime. These included pyridostigmine bromide pills (given to protect troops from the effects of nerve agents), depleted uranium munitions, and multiple simultaneous vaccinations including anthrax and botulinum toxin vaccines.