Clinical and Research News
Blast Injury Sequelae Linked to PTSD
Psychiatric News
Volume 43 Number 6 page 23-30

Soldiers surviving roadside bomb blasts in Iraq report higher rates of posttraumatic stress disorder, worse general health, and more somatic and other symptoms than those who have other injuries or were unharmed, said Col. Charles Hoge, M.C., a psychiatrist at the Walter Reed Army Institute of Research, and colleagues, in the January 31 New England Journal of Medicine (NEJM).FIG1

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PTSD, not mTBI, Links Blasts to Physical Symptoms

However, those increased symptoms, reported three to four months after leaving Iraq, may be more related to the PTSD that often accompanies a life-threatening event than to any brain injury, they said (see Careful Diagnosis at Time of Injury is Key to Recovery).

Hoge and colleagues also concluded that medical personnel treating mild traumatic brain injury (mTBI) should call it by its familiar civilian name—"concussion"—and tell soldiers that they are likely to recover.

Blasts cause more casualties than bullets in Iraq. A 2007 study by the Army found that explosions caused 78 percent of combat injuries and that head and neck injuries accounted for 30 percent of those injuries.

Some symptoms that follow blast experiences (such as irritability, fatigue, sleep problems, or forgetfulness) are not exclusively attributable to a brain injury, and may also have psychiatric associations such as PTSD or depression, they said.


The researchers surveyed two Army infantry brigades—one from the service's active component and one from the National Guard—three to four months after they returned from a year in Iraq.

Soldiers who lost consciousness, reported altered mental status (that is, were "dazed and confused"), or who couldn't remember their injury were considered to have mTBI. The soldiers were also assessed for combat exposure, somatic symptoms (with the PhQ-15), depression (with the PhQ-9), and some additional symptoms like memory, balance, concentration, and irritability. Data were self-reported, and no clinical examinations were used. Nearly all (95.5 percent) of the respondents were male.

Of the 2,525 soldiers who completed the survey, 124 (4.9 percent) reported at least a brief loss of consciousness, 260 (10.3 percent) claimed an injury with altered mental status, and 435 (17.2 percent) recorded other injuries not involving loss of consciousness or altered mental status.


Severity of TBI, judged by self-report, was associated with greater incidence of PTSD. Of those who lost consciousness, 43.9 percent met PTSD criteria, compared with 27.3 percent of those with altered mental status, 16.2 percent of those with other injuries, and 9.1 percent of the uninjured.

However, adjusting for PTSD and depression eliminated any initial association between mild traumatic brain injury and physical health symptoms (except for headache), reported Hoge and colleagues.

"These findings highlight the nonspecificity of postconcussional symptoms," said Hoge in an interview. "If the problem was TBI, we'd find these associations in PTSD and non-PTSD cases equally."

But that's not what the Army researchers found. For instance, regardless of the source of their injury, soldiers with PTSD recorded mainly high scores on the PhQ-15, a measure of current somatic complaints, while those without PTSD had much lower scores, said Hoge.

Furthermore, concussion also occurs in other settings, such as sports, but doesn't automatically produce PTSD. Athletes don't avoid reminders of their injury, they beg to get back into the game and "re-experience" the setting in which it happened. The difference lies in the context of the injury.

"PTSD does not occur in football concussions, so it's not the concussion itself that produces PTSD," he said. "PTSD occurs after motor vehicle accidents and in combat because of the threat that accompanies the injury. Memory encoding occurs in traumatic context."

Furthermore, there are many reasons other than concussion why soldiers would be dazed and confused during combat, he added.

Yet symptoms of the two conditions don't match perfectly, said a neuroscientist who has studied TBI.

"mTBI is a different entity than PTSD although there is a partial overlap in symptoms," said Harvey Levin, Ph.D., a professor in the departments of physical medicine and rehabilitation, neurosurgery, and psychiatry at Baylor College of Medicine, in an interview. "For instance, the axonal injury that characterizes TBI is not part of the clinical picture of PTSD, as far as we know."

Hoge's study was "impressive," said Levin, but it is limited (as Hoge also states) by a lack of imaging, clinical verification of injuries, and data on posttraumatic amnesia.

"Also the study shows very high rates of PTSD—two to three times civilian rates, which may reflect prolonged intense stress in combat soldiers," not just the effects of the blasts, said Levin.


In an editorial accompanying Hoge's article in NEJM, Richard Bryant, Ph.D., of the University of New South Wales in Sydney, Australia, refers to two possible mechanisms connecting TBI with PTSD. A biological model suggests that neural networks regulating anxiety might impair capacity to regulate the fear reaction. A cognitive model argues that mTBI could impair cognitive resources, leaving the patient less able to "engage appropriate cognitive strategies, which results in a greater incidence of PTSD," he said.

"There are no reliable means to differentiate between symptoms involving impaired awareness that are caused by severe stress or mild traumatic brain injury, so differential diagnosis is problematic," wrote Bryant. Loss of consciousness, being dazed, or amnesia for the event" can be attributed to acute stress responses" as well as any physical cause, wrote Bryant.

However, some fear that splitting the physical from the psychological effects of the blast could imply that subsequent PTSD or depression was" all in the head."

"Physical injury can produce psychiatric symptoms, and some psychological diagnoses may have neural consequences," said Levin.

"[Bryant] is characterizing the psychiatric disorders of depression and PTSD as nonbiologically based conditions of the brain," Robert Hales, M.D., M.B.A., professor and chair of psychiatry at the University of California, Davis, told Psychiatric News. "At the same time he speculates how TBI may worsen or prolong PTSD or major depression because of the brain injury."

Hales is a West Point graduate and served as an infantry officer before going to medical school at George Washington University while still on active duty. Following psychiatry training in the Army, he was subsequently assigned to Walter Reed Army Medical Center. He does not dismiss the aftereffects of mTBI.

"In my experience, it can have profound effects on mood, memory, motivation, and cognition," he said. "But 'concussion' is associated with less severe consequences. Mild TBI is a less stigmatizing and more accurate term that explains what happened to the brain. Also, if mTBI leads to increased incidence of PTSD, that can lead to higher rates of depression, suicide, and other chronic illnesses."

"We want to avoid giving the wrong message," said Col. Elspeth Cameron Ritchie, M.C., psychiatric consultant to the Army surgeon general, in an interview. "A head injury has many consequences, and we are still learning how they manifest over time."

Hoge does not minimize the consequences of mTBI but wants to place it in context. "At the point of injury, medics should check for other injuries or neurological symptoms," he told the Pentagon's Military Health System conference in February in Washington, D.C..

"Once in medical facilities or on return home, the soldier should be educated to normalize the outcome and promote the expectation of recovery. Use the term 'concussion.' And say that there is every evidence that it is like any other concussion, with a good prognosis. Protect patients from unneeded and undefinitive diagnostic tests."

Hales said that simple self-reporting is not enough to catch injuries following blasts. Fellow soldiers or squad leaders should be asked about how their buddies acted.

Both the course and treatment of mTBI and PTSD differ, said Levin.

"Generally, mTBI patients get better over time while PTSD gets worse," he said. "So reassurance and patient education are helpful right after the injury, but three or four months later, with comorbid PTSD, they are not sufficient."

"Experience with auto accidents shows that long-term cognitive impairments are possible, so patients should be followed for several years," said Hales. "you have to treat the symptomatology regardless of the etiology."

Department of Veterans Affairs' clinics now screen all veterans of fighting in Iraq and Afghanistan for TBI, illustrating yet another quandary for soldiers and a weakness in a self-reporting system.

"If you want to stay in the service, you want to minimize any deficits, but once you're out and you want help or compensation from the Va, you want to maximize symptoms," said Hales.

"Mild Traumatic Brain Injury in U.S. Soldiers Returning From Iraq" is posted at<http://content.nejm.org/cgi/content/full/358/5/453>.

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PTSD, not mTBI, Links Blasts to Physical Symptoms

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