related problems could reasonably be expected to result from these putative exposures. Indeed, the committee concludes that many key questions remain unanswered. This is true both with respect to the underlying cause or causes of the multisystem illness complex experienced by so many of the Gulf War soldiers, and also with respect to the adequacy of the experimental studies that have addressed the potential contribution of any external agent to the development, course, or persistence of this perplexing disorder. The committee concludes that it is essential to keep in mind that other etiologic factors may also play a role, and research into this matter must continue. The committee also concludes that it is possible that the specific cause(s) of the many and diverse symptoms reported by the veterans may never be determined given the limitations of the available data. To not acknowledge the uncertainty of what we know and the real possibility of not being able to identify a cause of the veterans’ illnesses would be a disservice to medical science and more importantly to the men and women who served so courageously in this battleground.
There are other areas of research that might be conducted on the etiology of Gulf War illness. The constellation of unexplained symptoms associated with the Gulf War illness complex could result from interplay between both biological and psychological factors. However, it is important to remember that there are a number of different causes for a disease, but due to the paucity of data it will be difficult to disentangle these for Gulf War illness. The symptoms of Gulf War illness could have a single cause, different causes in different individuals, or require multiple factors operating in combination.
Studies that lead to a better understanding of how biological and psychological factors give rise to variety of symptoms are needed as they may be the key to understanding and treating the Gulf War illness complex. For example, certain exposures may lead to alterations in blood–brain barrier permeability, neural pathways or transmitters, or neuroendocrine systems. It is also important to consider the effects of chronic stress, and, given the physical environment in the Persian Gulf, thermal dysregulation, an area that has received little attention to date.
After almost two decades of research on Gulf War veterans, important questions remain unanswered. What are the causes of the multisymptom illness experienced by veterans? How does predeployment health status influence the risk of developing Gulf War illness? Why do some veterans suffer a constellation of many symptoms whereas others experience isolated symptoms or only some components of the illness, and still others who served in the same battleground seemingly with similar exposures remain entirely without symptoms? Why do some veterans who were not on the ground in the Persian Gulf area (for example, Australian troops at sea), or others who arrived after the conclusion of the battle (for example, Danish forces), also experience symptoms of Gulf War illness? How severe and disabling are residual Gulf War symptoms? What are the most effective treatments for veterans who do suffer from multisymptom illness, and should the treatments vary depending on specific symptoms? Beyond the perplexing problem of Gulf War illness, what are the overall long-term physical and mental health consequences of serving in the Gulf War?
The committee believes that the path forward for veterans has two branches. The first is continued surveillance of Gulf War veterans. Such surveillance might include the following: