Adding to our understanding of Gulf War health issues.

In this edition of Psychological Medicine, research findings are reported from two studies of British Gulf War veterans (David et al. 2002; Everitt et al. 2002). Both studies were carried out at King’s College ‘Gulf War Illness Research Unit ’, which was established in 1996. The two studies were conducted to examine the causes of unexplained symptoms among Gulf War veterans. The results presented in these papers are important because they were derived from well-designed studies that employed a randomized sample of Gulf War veterans and two control populations of non-deployed ‘era’ veterans who served in the early 1990s and troops who participated in another hazardous deployment to Bosnia. In one study, cognitive function and mood disturbances were evaluated using a comprehensive battery of neuropsychological tests and rating scales (David et al. 2002). A significant proportion of Gulf War veterans reporting ill health were found to have both lower cognitive function scores and depressed mood compared to well Gulf War veterans, era veterans and Bosnia troops. Importantly, a strong association was found between depressed mood and poor performance on cognitive function tests. It is noteworthy that among ill Gulf War veterans, most cognitive function measures were within the normal range, although they were significantly lower than those of controls. Based on these and related research findings, the study investigators concluded that lower performance on cognitive function tests could be explained primarily by mood disturbances. However, they could not rule out the possibility that cognitive difficulties had led to depressed mood or that a neurotoxic environmental exposure had caused both health problems. Despite these uncertainties, the study findings clearly indicate that mood disturbance has to be considered as a potential confounder in studies of cognitive function among Gulf War veterans. In the second published study, the researchers used cluster analysis to determine whetherGulfWar and Bosnia veterans can be distinguished by the pattern of their medically unexplained symptoms (Everitt et al. 2002). In contrast to other surveys of Gulf War veterans, which used another sophisticated statistical technique, factor analysis, to try to identify a unique ‘Gulf War syndrome’, this survey attempted to group study participants with related symptoms by geographic location of deployment. Gulf War and Bosnia veterans were asked about the presence during the prior month of 50 non-specific symptoms and about the severity of any symptoms. A unique syndrome could not be distinguished among veterans deployed to the Persian Gulf by this analysis of self-reported symptoms. The results of these two studies are in agreement with other large, randomized and controlled studies of Gulf War veterans. A consistent pattern of either symptoms or clinical signs has not been identified that points to the presence of a unique,war-related physical disease.Moreover, similar nonspecific symptoms have been reported in these studies by control groups of veterans who were not deployed to the Persian Gulf. The research methodologies employed in the two studies deserve comment because they have been used frequently in the search for a uniqueGulfWar syndrome. Both studies utilized symptom reports to group study subjects and complex statistical techniques to analyse clinical data. Studies that rely on