by Kristina Fiore

After combat duty in Iraq, members of the National Guard appear to have higher rates of mental health problems than soldiers in the Active Component, researchers have found.

Rates of post-traumatic stress disorder (PTSD) with serious functional impairment increased from about 7% to more than 12% over a nine-month period, compared with only about a 1% increase among those in the Active Component, according to Jeffrey L. Thomas, PhD, of Walter Reed Army Institute in Silver Spring, Md.

They reported their findings in the June issue of Archives of General Psychiatry.

“The emergence of differences . . . likely does not have to do with the differences in the health effects of combat, but rather with other variables related to readjustment to civilian life or access to healthcare,” they wrote.

Longitudinal studies have shown that the incidence of PTSD is two to three times higher among those exposed to combat than those not exposed. But these studies have shown varying prevalences of PTSD and depression and have not assessed comorbidities including functional impairment, alcohol misuse, or aggressive behaviors.

So the researchers assessed 18,305 soldiers from four Active Component and two National Guard infantry brigade combat teams, all of whom had combat exposure.

The soldiers completed mental health surveys between 2004 and 2007, at three and 12 months following their deployment.

Overall, the researchers found that rates of PTSD and depression ranged from 9% to 31%, depending on the level of functional impairment reported.

Generally, National Guard soldiers had significant increases in depression and PTSD symptoms between the three and 12-month time points, while depression symptoms remained stable for Active Component soldiers. This group also had increases in PTSD symptoms, but not as great as those among the National Guard members.

“Symptoms of PTSD increased significantly in both groups but with much larger increases observed in National Guard participants,” they wrote.

For instance, the DSM-IV-diagnosed rates of PTSD with serious functional impairment in the Active Component was 7.7% at three months and 8.9% after a year. For the National Guard, those numbers were 6.7% and 12.4%, respectively.

Using the least stringent definition of PTSD, those rates ranged from 20.7% among the Active Component at three months to 30.5% among the National Guard component after a year.

The difference likely has to do with readjustment to civilian life or access to healthcare, because National Guard soldiers return to civilian status following their deployment. Thus, they don’t have the same uninterrupted access to military medical care as Active Component soldiers, the researchers wrote.

Regarding depression, the researchers found that prevalence rates — based on the Patient Health Questionnaire (PHQ) — ranged from 11.5% among National Guard members at three months to 16% among Active Component soldiers at that same time point.

Using the PHQ plus serious functional impairment scores, those rates were 8.3% and 8.5% for the Active Component at the two time points, and 5% and 7.3% for the National Guard, respectively.

Alcohol misuse or aggressive behavior were present in about half of the cases, the researchers said. While these comorbidities increased between three months and one year postdeployment for National Guard soldiers, there were no changes over that time for the Active Component group.

The researchers said the data “make clear that, at 12 months following deployment, many combat soldiers have not psychologically recovered.”

They concluded that these high levels of comorbidity highlight the need for postdeployment screening: “These findings indicate that it may be beneficial to screen for alcohol and aggressive behaviors when soldiers present for treatment of PTSD or depression.”

The study was limited by its cross-sectional design; data was not longitudinal since respondents were surveyed anonymously and ill or injured soldiers were not included, likely decreasing rather than increasing reporting of mental health problems.

Kristina Fiore is a MedPage Today staff writer.

Originally published in MedPage Today. Visit MedPageToday.com for more psychiatry news.