Gulf War Illness: Lessons from medically unexplained symptoms

Abstract

Service in the Persian Gulf in 1991 is associated with increased reporting of symptoms and distress in a proportion of those who served there. Yet despite clear evidence of an increase in symptom burden and a decrease in well being, exhaustive clinical and laboratory based scientific research has failed to document many reproducible biomedical abnormalities in this group. Likewise, there has been no evidence of an increase in disease related mortality. Formal psychiatric disorders are twice as common in Gulf War veterans, as might be expected in the aftermath of any conflict, but this too is insufficient to explain the ill-health observed. Many service personnel who returned unwell believe that they have Gulf War Syndrome, and that their ill-health is due to exposures that they encountered in theatre. Research on multiple exposures to date has not generated a plausible aetiological mechanism for veterans' ill-health.

Even if medical research has failed to provide a satisfactory explanation, it remains the case that many of those affected continue to be unwell and disabled some 15 years after returning from combat. For this reason, it is time that more attention is given to developing effective interventions to relieve their ill-health and distress. In this review we discuss the importance of the wider social context, individual illness beliefs and attributions and go on to outline a model of continuing ill-health in Gulf veterans. The review concludes with some suggestions for future research priorities, in particular the need for further qualitative studies to further our understanding of the illness, in order that better treatments may be developed.

Introduction

In 1991, nearly 1 million servicemen and women from the United States, United Kingdom, France, Canada, Australia, Denmark and 30 other nations were deployed in the Persian Gulf. After a concentrated air assault, the ground offensive targeted against the Iraq invasion of Kuwait lasted only 100 hours and was one of the shortest and most effective periods of land-based conflict in history. With fewer than 400 casualties in Allied Forces troops (approximately half of which were due to accidents and “friendly fire” rather than combat), it was hailed as a resounding military success, and a testament to the efficiency and omnipotence of the new technologies of war, the so called “revolution in military affairs” (Cordesman & Wagner, 1996).

Within months of service personnel returning, the first reports of ill-health in US returnees began to emerge on websites and in primary care clinics. Early studies were based on anecdotes and apparent clusters of ill health and/or birth defects. In response, self-selected voluntary registers were instituted (Murphy et al., 1999). Later these were followed by larger population-based epidemiological studies, and these were collated in turn into comprehensive and definitive meta-analyses/systematic reviews of the evidence base both in the USA (Institute of Medicine, 1999, Institute of Medicine, 2001) and UK (Medical Research Council, 2003).

An increase in distress and unexplained symptoms is beyond dispute. Gulf veterans report having more symptoms than non-Gulf veterans (Fukuda et al., 1998, Gray et al., 1996, Unwin et al., 1999) and suffer more severely from them. Common complaints range from non-specific constitutional symptoms such as tiredness and headache, to specific neurological complaints such as numbness and limb weakness (Unwin et al., 1999). Cognitive complaints such as loss of concentration, memory problems and low mood are also common (David et al., 2002). Similar clinical pictures have now been reported from the UK (Cherry et al., 2001b, Unwin et al., 1999), Canada (Goss Gilroy Inc., 1998), USA (The Iowa Persian Gulf Study Group, 1997), Australia (Ikin et al., 2004, Kelsall et al., 2004) and Denmark (Ishoy et al., 1999). In the meantime, the term Gulf War Syndrome (GWS) has entered the lexicon to describe these symptoms, although it is almost certain that no actual new syndrome is involved (Institute of Medicine, 2001).

All commentators point out that there were several challenging methodological problems in carrying out Gulf War research, some of which were only partially overcome. These difficulties have arisen in the main because of the significant delay between the point at which illnesses were first identified by veterans and the setting up and reporting of big epidemiological studies examining health. Contemporaneous records of health were not kept systematically by the military at that time either in the USA or the UK, and routine post-deployment health surveillance was minimal. Thus, whilst some of the research done has been prospective and followed up veterans since the war (King et al., 2000), none of the large studies have been able to use pre-deployment data; as such, recall bias for what happened in theatre or before is a major problem, as it would be for any retrospective study. Other problems include low-response rates, ascertainment bias, problems identifying suitable control groups, and problems defining meaningful outcomes to study (Hotopf & Wessely, 2005).

Studies which attempt to unpick the relationship between symptoms and exposure are particularly hampered by recall bias; it is never possible to obtain reliable, independent and contemporaneous reports of an individual's exposure during war and retrospective self report is not reliable (McCauley et al., 1999, Wessely et al., 2003).

In this review, after acquainting the reader with a summary of the salient findings to date, we focus on novel ways to understand at least a part of Gulf veterans' ill-health, and consider future treatment approaches based on this approach.