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From: The Rheumatologist, March 2011

Similarities to Fibromyalgia Found in Post-War Illness

Many questions remain about these chronic multisymptom illnesses

by By Vanessa Caceres

ATLANTA—In every war in which the United States has participated, returning veterans have experienced a similar cluster of symptoms.1 This cluster has had different names through time—Soldier’s Heart, Effort Syndrome, Combat Stress Reaction, Agent Orange, and mild traumatic brain injury. Although studies have validated these symptom clusters to varying degrees, one thing the symptoms seem to have in common is their similarity to what fibromyalgia patients experience—pain, fatigue, and memory problems, according to Daniel J. Clauw, MD, professor of anesthesiology, medicine (rheumatology), and psychiatry and director of the Chronic Pain and Fatigue Research Center at the University of Michigan in Ann Arbor.

Dr. Clauw discussed the common cluster of symptoms experienced by veterans of the first Gulf War during the ACR/ARHP 2010 Scientific Meeting session, “Musculoskeletal Pain and Returning Military Personnel.” [Editor’s Note: This session was recorded and is available via ACR SessionSelect at]

Military Mystery

Although there were relatively few casualties among the 700,000 U.S. troops sent to the Gulf in the early 1990s, many experienced similar symptoms upon their return. “There were many soldiers complaining of joint and muscle pain, headaches, fatigue, difficulties with memory, rash, and gastrointestinal disturbances,” Dr. Clauw said. However, “their medical evaluations were generally unremarkable.”

The government spent millions of dollars researching the symptom cluster but could not pinpoint a specific illness. This situation led veterans’ groups to become distrustful of the U.S. government’s response to Gulf War veterans’ symptoms, Dr. Clauw explained. Now, many years later, after a number of Institute of Medicine and congressional panels—many of which Dr. Clauw took part or testified in—he said that a few things are clear. “The symptoms that Gulf War vets suffer are the exact same cluster of symptoms that occur in the general population and go by names such as fibromyalgia, chronic fatigue syndrome, and somatoform disorders,” he noted.

Although one study implicated vaccines given at the time of deployment that may have led to the constellation of symptoms, there have otherwise been no specific exposures that seem to have led to this condition in veterans, Dr. Clauw said. At the same time, “it’s very clear these symptoms were more common in deployed vets than nondeployed vets,” he said.

When we send people to war, they come back with pain, fatigue, and other symptoms. We need to do a better job of understanding the underlying pathogenesis.

—Daniel J. Clauw, MD

In 1998, the Centers for Disease Control and Prevention coined the term “chronic multisymptom illnesses” to describe what these veterans were experiencing.2 The study authors defined someone as experiencing the illness if they had one or more chronic symptoms in at least two of three categories—fatigue, mood/cognition, and musculoskeletal.

“The prevalence of mild-to-moderate and severe cases was 39% and 6%, respectively, among 1,155 Gulf War veterans compared with 14% and 0.7% among 2,520 nondeployed personnel,” according to the study.

“This study and subsequent ones demonstrated that 10% to 15% of population suffers a syndrome like this,” Dr. Clauw said. “…Yet [veterans] with these symptoms were labeled as having Gulf War syndrome rather than fibromyalgia or irritable bowel syndrome.”

Veterans experiencing chronic multisymptom illness were more likely to experience tension or migraine headaches; affective disorders; temporomandibular joint syndrome; weight fluctuations; night sweats; weakness; sleep disturbances; cognitive difficulties; ear, nose, and throat complaints; vestibular complaints; and noncardiac chest pain, among other symptoms. “Any of you who see fibromyalgia patients sees these symptoms,” Dr. Clauw said.

Search for a Cause

Dr. Clauw and other investigators set out to find possible causes for this symptom cluster. One angle considered was how often similar symptoms occur after natural disasters (e.g., hurricanes and earthquakes) or manmade disasters (e.g., the Three Mile Island accident in Pennsylvania in 1979).3 While conducting research for a review article on this topic, Dr. Clauw said a few things became clear. “Until that time in 2003, natural disasters led to very few incidences of mood disorders or post-traumatic stress disorder and even smaller increases of chronic fatigue syndrome,” he noted. “In manmade disasters, there were fairly high rates of fibromyalgia and pain at different rates.”

However, Dr. Clauw said that Hurricane Katrina somewhat changed this trend, because a large number of physical and psychological symptoms have been associated with the disaster. “Katrina started as a natural disaster and then became a manmade disaster because of the way it was handled,” he said.

The research revealed that natural disasters may cause less pain and fewer other symptoms because of the rally of human support that follows them. “The hypothesis is that, with natural disasters such as hurricanes, floods, and fires, there are a lot of people who help and come together—people don’t feel out alone on an island, and there’s not the worry of exposures [to something toxic],” Dr. Clauw said.

A sense of support from others, along with a sense of control over what is happening in one’s environment, may make a difference in triggering illness such as that experienced by the Gulf War veterans, Dr. Clauw said. He gave the analogy of working hard at a job that one enjoys versus being asked to do a short but unenjoyable task someone else requests—the latter may cause more stress even though it takes less time. “There’s a lot of work right now on instilling resiliency and giving people a sense of control and support,” he said.

Genes and Gender

Central pain conditions seem to also be more common in women—although more men than women were sent to the first Gulf War, the women who did go experienced a higher rate of chronic multisymptom illness. Additionally, genetic underpinnings are a known trigger. At least four genes are associated with pain sensitivity, and these have been shown to be more common in fibromyalgia, irritable bowel syndrome, and other conditions, according to Dr. Clauw.

“Depending on the genes you are born with, it may be more likely that these symptoms will happen to you after trauma,” Dr. Clauw said, going on to say hyperalgesia or allodynia are common terms for people who experience problems such as fibromyalgia, tension headaches and migraines, irritable bowel syndrome, and other symptoms.

Although certain studies have tracked sensitivity to pain to stressors from childhood, Dr. Clauw said it may be surprising to know that psychological distress doesn’t necessarily trigger pain right away. “Baseline psychological distress is only weakly associated with the subsequent development of chronic widespread pain,” he said. “The overwhelming number of individuals did not have high levels of stress before they had widespread pain.”

Two studies that took place following the terrorist attacks on September 11, 2001, led to further study of the relationship of stress and development of symptoms. In one study, 1,312 women in the New York City metro area were initially surveyed for pain and psychiatric symptoms before September 11 and then recontacted six months later to assess symptoms and terrorism-related exposures. Investigators compared “fibromyalgia-like” four-quadrant pain reports at baseline and follow-up.4 They found that event exposure did not relate to the fibromyalgia-like symptoms and that depressive symptoms at baseline did not interact with exposure to the terrorist attacks.

In the second study, eight fibromyalgia patients in the Washington, D.C. area used handheld devices to rate their pain on a scale four to six times a day.5 Patients rated their pain daily from August 28, 2001, to September 25, 2001. The study found that pain levels in the days after the attack did not differ significantly than pain levels before the attack. “This result is consistent with previous work suggesting minor daily problems rather than major events may drive somatic symptom expression,” the study investigators wrote, although they acknowledged that their study size was small.

Naturally, the kinds of medication that work best for fibromyalgia and similar patients, such as tricyclic compounds, serotonin–norepinephrine reuptake inhibitors, and norepinephrine selective reuptake inhibitors, are different from opioids and other medicines, including antiinflammatory drugs, that work for other types of pain and pain patients, Dr. Clauw said.

He noted that this line of research requires more investigation. “When we send people to war, they come back with pain, fatigue, and other symptoms. We need to do a better job of understanding the underlying pathogenesis,” he said.

Vanessa Caceres is a medical writer in Bradenton, Florida.


  1. Hyams KC, Wignall FS, Roswell R. War syndromes and their evaluation: From the U.S. Civil War to the Persian Gulf War. Ann Intern Med. 1996;125:398-405.
  2. Fukuda K, Nisenbaum R, Stewart G, et al. Chronic multisymptom illness affecting Air Force veterans of the Gulf War. JAMA. 1998;280:981-988.
  3. Clauw DJ, Engel CC Jr, Aronowitz R, et al. Unexplained symptoms after terrorism and war: An expert consensus statement. J Occup Environ Med. 2003;45:1040-1048.
  4. Raphael KG, Natelson BH, Janal MN, Nayak S. A community-based survey of fibromyalgia-like pain complaints following the World Trade Center terrorist attacks. Pain. 2002;100:131-139.
  5. Williams DA, Brown SC, Clauw DJ, Gendreau RM. Self-reported symptoms before and after September 11 in patients with fibromyalgia. JAMA. 2003;289:1637-1638.


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