Benedikt and Kolb (1986) examined case histories of 225 veterans who were referred to a VA pain clinic for the treatment of chronic pain between 1978 and 1984. Of the 225 patients, 22 later received a diagnosis of PTSD (two were World War II veterans, and 20 were Vietnam veterans); this suggests a high prevalence of PTSD (10%) in patients who have chronic pain.
Hoge et al. (2007) found that soldiers who screened positive for PTSD (n = 468) a year after their return from combat duty in Iraq reported more pain symptoms than those negative for PTSD (n = 2347). Half the soldiers with PTSD indicated that they were “bothered a lot” by pain in their arms, legs, or joints (OR 2.89, 95% CI 2.35-3.57); 40% were bothered by back pain (OR 3.36, 95% CI 2.72-4.16); and almost 32% had headaches (OR 4.25, 95% CI 3.32-5.42), compared with 26%, 22%, and 10%, respectively, of soldiers without PTSD. Several other studies report that Gulf War veterans with PTSD had more pain symptoms than did veterans without PTSD (Engel et al. 2000; Spiro et al. 2006).
It has been reported that one-fifth of U.S. Army soldiers returning from OIF have a diagnosis of migraines and that this group has nearly twice as high a risk of depression, PTSD, and other psychiatric disorders as returning soldiers who do not have migraines. When assessed within 90 days of their return from a 1-year tour of duty, 19% of the 2200 veterans had migraines, 32% had depression, 22% had PTSD, and 13% had anxiety. Of those with migraines, 50% were also depressed, 39% also had PTSD, and 22% also had anxiety disorders compared with 27%, 18%, and 10% of those who did not have migraines (Erickson and Diamond 2007).
Those studies suggest that PTSD and chronic pain are frequently comorbid and that each disorder has the potential to exacerbate the symptoms of the other (Otis et al. 2003).
Male and female veterans who have been deployed to a war zone, regardless of the war in which they served, report more symptoms and poorer health than do their nondeployed counterparts. Symptoms range from severe, such as chest pain and numbing in the extremities, to minor, such as loss of appetite. Combat exposure was associated with increased number and severity of symptoms.
The committee identified eight studies that assessed the prevalence of unexplained illness in Gulf War veterans compared with nondeployed veterans and found mixed results. Some researchers have attempted to cluster the symptoms into new diseases but in general the symptoms are too broad and nonspecific to suggest the presence of a new illness specific to the Gulf War (see IOM 2006). Fukuda et al. (1998) developed the case definition for chronic multisymptom illness based on an Air Force unit deployed to the Gulf War. A later study by Blanchard et al. (2006) found that deployed veterans reported higher rates of nearly all symptoms or sets of symptoms than their nondeployed counterparts 10 years after the war. Four other studies also found higher rates of unexplained illness in deployed Gulf War veterans than in nondeployed Gulf War veterans, but the use of self-reported symptoms introduced the possibility of reporting bias, and the low participation rates in some of the studies introduced the possibility of selection bias.
The three hospitalization studies did not find a consistent association between deployment and a diagnosis of unexplained illness. Although the Knoke and Gray (1998) and Gray et al. (1996) hospitalization studies did not demonstrate an increase in unexplained illness in active-duty Gulf War veterans, the Gray et al. (2000) study reviewed the hospital discharge diagnoses of Gulf War veterans and found an increase in hospitalization for unexplained illness