Persistent PTSD Symptoms Linked to Reduced Cognitive Function in Returning Veterans

Caroline Cassels

September 17, 2009

September 17, 2009 — Posttraumatic stress disorder (PTSD) appears to be linked to reduced attention in soldiers 1 year after returning from Iraq — a finding researchers say highlights the need for early screening and intervention in this population.

In a prospective cohort study, investigators at the Boston Veterans Affairs Healthcare System and Boston University School of Medicine, Massachusetts, found that greater PTSD symptoms were associated with poorer attention in solders tested at 1-year follow-up, but not in recently returned soldiers.

Further, they found that those who experienced greater combat intensity had faster reaction times regardless of time since deployment.

"The most important finding is that PTSD by itself didn't seem to make a difference on how people performed on attention or other kinds of cognitive tests. But if an individual had PTSD for an extended period of time, it did make a difference," study investigator Jennifer J. Vasterling, PhD, said in an interview.

According to the authors, the results confirm previous research suggesting that prolonged exposure to life-threatening situations can trigger neurobiological alterations in the noradrenergic and neuroendocrine systems, resulting in heightened behavioral reactivity but dampened attention, learning, and memory in response to nonthreatening stimuli and events.

The study is published in the September issue of the Archives of General Psychiatry.

Enduring Changes?

These latest findings are from the Neurocognition Deployment Health Study. Initiated in 2002, this longitudinal study was launched in response to cognitive problems reported by veterans from previous wars. The overall goal of the study is to examine neuropsychological outcomes in Iraq war veterans over time.

Previous research in Iraq veterans has shown that neuropsychological changes occur after deployment. However, it is not known, said Dr. Vasterling, whether such changes endure over time after veterans return home.

To examine this issue, investigators studied 268 men and women who were regular active-duty US Army soldiers who served between 2003 and 2006. All participants underwent neuropsychological testing to assess response time, attention, and memory before and after deployment.

In addition, investigators also assessed PTSD and depression symptoms, as well as combat intensity.


A group of 164 subjects was assessed both immediately and 1 year after their return from Iraq. A second group of 104 participants returned more recently and were assessed before deployment and a median of 122 days after returning home.

Each assessment documented current demographic and military information and risk factors for neuropsychological disorders such as neurodevelopmental disorders, psychiatric disorders, and brain injury.

In addition, situational factors such as alcohol use that could potentially affect neuropsychological performance were also assessed.

Subjects underwent a battery of neuropsychological tests including the Neurobehavioral Evaluation System, 3d edition; Continuous Performance Task; Automated Neuropsychological Assessment Metric; and Wechsler Memory Scale, 3rd edition.

Intensity of combat exposure was evaluated using the modified version of the Deployment Risk and Resilience Inventory, combat experiences module. PTSD and depression symptoms were assessed using the PTSD Checklist and the Center for Epidemiological Studies Depression Scale, 9-item version. Higher scores on these tests indicate greater exposure or symptoms.

Persistent Symptoms

Investigators found that among the 104 recently returning service members, PTSD symptoms were not associated with poorer attention at a median of 122 days after returning from Iraq. However, this was not the case for veterans with PTSD symptoms who were assessed at 1 year.

"We found that for individuals whose stress-related symptoms persist over time, the effect seems to broaden out beyond psychological symptoms and adversely affect cognitive function, which also has a potential to negatively impact their lives," said Dr. Vasterling.

However, she added, it is important to note that the level of attention impairment was relatively mild. Nevertheless, she said, the study highlights the need for early intervention.

"It is so important to be sure people are doing well. It is not just their emotions or mood that should be the focus, but clinicians need to ask veterans broader questions about how they are doing in their daily lives such as whether they are able to focus at work," said Dr. Vasterling.

Need to Act Quickly

In terms of public health implications, Dr. Vasterling said the findings underline the need for public health policies aimed at preventing acute symptoms from becoming chronic.

"From a public health perspective, there is a definite need to act fast to try and help people cope, manage, and recover," she said.

The study also showed that combat intensity decreased reaction times and that this effect continued after veterans returned home.

Hypervigilance, including the ability to act quickly, said Dr. Vasterling, is an adaptive response that sometimes develops in response to potentially life-threatening situations. Although this survival instinct is positive in combat situations, if it continues in daily life it can become problematic.

Dr. Vasterling said that her team will continue to follow-up this cohort and specifically look over time at psychosocial outcomes including PTSD, depression, and daily functioning.

In a smaller group of patients, the researchers also plan to administer performance-based tests to determine long-term neuropsychological outcomes.

The authors have disclosed no relevant financial relationships.

Arch Gen Psychiatry. 2009;66:996–1004. Abstract


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