A new study of U. S. armed forces who served in Iraq and Afghanistan from 2000 to 2006 revealed that combat duty not surprisingly increased the incidence of depression in soldiers. The study, conducted by the U.S. Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio, focused on subjects from all of the major military service branches.

The Wright-Patterson study found that the new diagnoses for depression among personnel deployed was 6 percent for men and 16 percent for women among the more than 40,0000 members who participated in the survey, all of whom had been free of depression before deployment. According to a report in the American Journal of Public Health, “combat-deployed men and women were at increased risk for new-onset depression compared with non-deployed men and women.”

Further analysis suggests that male combat specialists have a lower risk for depressive disorders than male soldiers in health or supportive care positions. One theory for this difference was the combat training those who are deployed receive. Another factor could be what the study called “military hardiness.” Other factors that increase the risk of depression among men were identified as an alcohol-dependence, smoking, and an age factor: the younger the personnel, the more likely the increase of depressive symptoms. Among women, marital status, ethnicity and Naval or Coast Guard duty increased the risk of depressive symptoms.

Not surprisingly, male and females who were deployed ran the increased risk of Post Traumatic Stress Disorder . PTSD, sometimes called “”battle fatigue or “shell-shock,” is often triggered as a result of witnessing or participating in traumatic events. Symptoms of the disorder include frightening flash-backs, hallucinations and nightmares. Anxiety and depressive symptoms are also present in patients suffering from PTSD. Depression has long been a counterpart of PTSD as both illnesses share a variety of symptoms.

According to a study conducted by John D. Corrigan and Thomas B. Cole, published in 2008 by the Journal of the American Medical Asociation, more than 18 percent of military personnel returning from service in Iraq and Afghanistan met the criteria for PTSD or depression. There was also an increased risk for traumatic brain injuries, as well as a propensity for substance abuse.

In a recent article in USA TODAY, it is estimated that 15 to 20 percent of all soldiers fighting in Iraq and Afghanistan suffer from depression according to a U. S. Surgeon General’s report, the fifth such report since 2003. As soldiers are assigned successive deployments the emotional stress and onset of mental illness is increased. Studies increasingly show that the emotional distress of more than one deployment increases the current cases of PTSD in soldiers on active duty, as well as soldiers who have finished military service.