TUESDAY, July 5 (HealthDay News) -- Children with a parent on long-term military deployment in Iraq or Afghanistan are at increased risk for mental health problems, new research suggests.

In the study, published in the July 4 online edition of the Archives of Pediatrics and Adolescent Medicine, researchers examined the medical records of 307,520 U.S. children, aged 5 to 17, who had at least one parent on active duty in the U.S. Army and received outpatient care between 2003 and 2006.

During that time period, nearly 17 percent of the children were diagnosed with a mental health disorder. The most common conditions were depression, behavioral problems, anxiety, stress and sleep disorders, the investigators found.

More than 62 percent of the children's parents were deployed at least once during the study period, with deployments averaging 11 months. Mental health problems were more likely to be diagnosed among children who had a parent who was deployed at least once to Iraq or Afghanistan. The risk of a mental health problem among the children rose with increased length of parents' deployment.

"We observed a clear dose-response pattern such that children of parents who spent more time deployed between 2003 and 2006 fared worse than children whose parents were deployed for a shorter duration," wrote Alyssa J. Mansfield, then of the University of North Carolina at Chapel Hill, now of the National Center for Posttraumatic Stress Disorder in Honolulu, and colleagues. "Similar to findings among military spouses, prolonged deployment appears to be taking a mental health toll on children."

In an accompanying commentary, Dr. Stephen J. Cozza, from the Uniformed Services University School of Medicine in Bethesda, Md., noted that as of 2009, 44 percent of active duty military members have children (an estimated total of 1.2 million children), in addition to 43 percent of Reserve and National Guard members. Since 2001, about 2 million U.S. military personnel have deployed at least once.

The study provides "an important contribution to our understanding of a child's health and its relationship to parental combat deployment," Cozza said in a journal news release.

"Brief screening for anxiety, depression, behavioral problems, academic difficulties, peer relational problems, or high-risk behaviors (such as substance misuse or unsafe sexual practices) is warranted and will help identify treatment needs," Cozza concluded.

More information

The U.S. Army Center for Health Promotion and Preventive Medicine offers tips for supporting children of a military parent who is deploying.