The study, published in the Archives of Pediatrics and Adolescent Medicine, analyzed medical records of 307,520 children of active-duty Army personnel, aged 5 to 17 years old. It found almost 17 percent of them exhibited mental health problems.
"Children of parents who spent more time deployed between 2003 and 2006 fared worse than children whose parents were deployed for a shorter duration," the study's researchers wrote.
The lead researcher was Alyssa Mansfield, who was at the University of North Carolina at Chapel Hill at the time the study was conducted.
The U.S. Army reported some 562,000 members in active duty and more than 570,000 children of such members in 2010. Just under two-thirds of all active-duty servicemen and women were married and 15 percent were raising children as single parents.
The children whose parents deployed at least once, for an average of 11 months, as part of the U.S. Operation Iraqi Freedom or Operation Enduring Freedom in Afghanistan were especially likely to suffer from adjustment, behavioral, depressive or stress disorders than those whose parents never went to war, the study found.
Boys were more likely to have mental health problems than girls, according to the report, which reviewed records for patients cared for at military medical facilities and at civilian facilities using military medical insurance.
"We used to think about deployment as a single experience: I go, I'm away, it's difficult and then I come back. Well, it's a way of life in the military that deployments continue to occur and families have to manage the consequences," said Dr. Stephen Cozza, psychiatry professor at the Uniformed Services University of the Health Sciences.
Cozza has studied the issue and wrote an editorial accompanying the report.
"These are consequences that aren't necessarily short-term," he said. The challenges don't necessarily end with the final return home, he said, as soldiers may bring back their own mental health issues which affect relationships with their children.