Headway being made in developing biomarkers for PTSD




HUNTINGTON BEACH, CALIF. – Researchers are making significant headway in developing objective, reliable, and valid biomarkers to discriminate individuals with warzone post traumatic stress disorder from healthy controls, according to Dr. Charles R. Marmar.

“It’s clear that over the next four or five years we will identify very clear biological, psychological, and other behavioral risk and resilience profiles,” Dr. Marmar told attendees at the annual meeting of the American College of Psychiatrists.

Currently, clinicians largely rely on patient self-reports and clinical observations to diagnose PTSD in military personnel, said Dr. Marmar, professor and chair of the department of psychiatry at NYU Langone Medical Center and director of NYU’s Steven and Alexandra Cohen Veterans Center.

Dr. Charles R. Marmar

Dr. Charles R. Marmar

“The problem from the military and law enforcement perspective is that the majority of war fighters experience tremendous stigma in acknowledging their symptoms, particularly active duty military personnel,” he said. “A minority will exaggerate to avoid service or for compensation. Given that we’ve had nearly three million men and women serve in Iraq and Afghanistan, and the fact that we have no objective way yet of determining which ones continue to be fit for redeployment, which ones are in urgent need of help, and which ones deserve compensation, we need to develop better ways to determine if treatments are effective, to inform new treatment selection, and to define new targets for treatment.”

The scope of the problem is underscored in an analysis of data from 289,328 veterans entering VA Healthcare for the first time beginning on April 1, 2002 through March 31, 2006 (Am J. Pub. Health 2009;99[9]:1651-8). Prior to the invasion of Iraq, the distribution of mental health problems was very similar among veterans as in the general population: depression being most common, and low rates of PTSD and alcohol and drug abuse. However, “with each quarter since the invasion of Iraq, there’s been an incubative growth in the prevalence of PTSD, which has now eclipsed depression,” Dr. Marmar said. “We have a toll, a generational effect which looks similar in magnitude with the Vietnam War, both in the number of men and women who serve and in the prevalence of PTSD, depression and alcohol- and drug-related disorders.”

In the general population, risk factors include female sex, child abuse, genetics, which in twin studies account for 30-40% of the risk, lower IQ and lower educational attainment, stressful life events in the prior and following year, and panic reaction at the time of event, such as racing heart, shaking, and sweating.

According to findings from the National Vietnam Veterans Readjustment Study, risk factors for chronic warzone PTSD include high school dropout rate, history of child abuse, high warzone exposure, serious warzone injury, killing combatants, prisoners, and civilians, peritraumatic dissociation, hostile homecoming, post-discharge trauma, and genetics. “These are the risk profiles, and they should give us some clues about where to look for biological factors,” Dr. Marmar said.

The risks of service are not limited to stress, anxiety, depression, alcohol and drug abuse, or traumatic brain injury (TBI). “If you compare men and women returning from Iraq and Afghanistan with no mental health issues to those who have a diagnosis of either PTSD, depression, or the combination, the [diagnosed] cases have 2.5 times the risk of tobacco use, hypertension, dyslipidemia, obesity, and type 2 diabetes,” he said. “These are people in their late 20s and early 30s. So the costs of warzone-related stress and depression are enormous on general health.”

Dr. Marmar presented preliminary findings from the ongoing PTSD Systems Biology Consortium, an effort by researchers at seven universities to establish biomarkers for PTSD. Funded by the Department of Defense, the National Institutes of Health, and other sources, the consortium is comprised of integrated cores including neurocognition, genetics, structural and functional brain imaging, endocrinology, metabolism, genomics, proteomics, metabolomics, and bioinformatics.

To date, the researchers have screened 2,215 veterans from service in Iraq and Afghanistan, all of whom have been deployed to war at least once. Cases were PTSD positive and had a CAPS (Clinician-Administered PTSD scale) score of 20 or greater. Controls were PTSD negative and had a CAPS score of less than 20. They excluded subjects with lifetime psychosis, bipolar disorder, or OCD, as well as alcohol dependence in the past eight months, and drug abuse in the past year. They also excluded veterans with TBI “because we’re trying to be very careful to see if we can get a biological signal comparing combat PTSD cases with controls,” Dr. Marmar noted.

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