Although drone operators may be far from the battlefield, they can still develop symptoms of post-traumatic stress disorder (PTSD), a new study shows.

About 1,000 United States Air Force drone operators took part in the study, and researchers found that 4.3 percent of them experienced moderate to severe PTSD. In comparison, between 10 and 18 percent of military personnel returning from deployment typically are diagnosed with PTSD, the researchers wrote.

"I would say that, even though the percentage is small, it is still a very important number, and something that we would want to take seriously so that we make sure that the folks that are performing their job are effectively screened for this condition and get the help that they [may] need," said study author Wayne Chappelle, a clinical psychologist who consults for the USAF School of Aerospace Medicine at Wright Patterson Air Force Base in Dayton, Ohio.

The percentage of drone operators in the study who had PTSD was lower than the percentage of people in the U.S. general population who have the condition, which is 8.7 percent, according to the 2013 data from the American Psychiatric Association cited in the study.

The drone operators in the study completed questionnaires that listed 17 symptoms characteristic of PTSD, such as recurring nightmares, intrusive thoughts, trouble falling asleep and difficulty concentrating. [5 Controversial Mental Health Treatments]

The researchers also found that "there are really no substantive differences" between symptoms of PTSD in drone operators and other military personnel, Chappelle told Live Science.

The drone operators who had worked for 25 months or more, and those working 51 or more hours weekly were more likely to experience PTSD symptoms than operators who had worked for less time, or fewer hours per week.

Whether someone develops PTSD after a traumatic event depends on how they can process it, Chappelle said. It is not completely clear why some people seem to process events better than others.

"It is likely that multiple factors are at play," such as genetics or past exposure to trauma, in determining whether a person will experience PTSD, Chappelle said.

Although drone operators are not on the actual battlefield, they operate aircraft "that still affect battlefield operations, and many other operations, [and therefore] it is important that we maintain airmen who are healthy, who are fit and that we are able to identify those airmen that may be struggling with some kind of psychological or physical condition that could in fact impair their performance or reduce longevity," Chappelle said.

Drone operators suffering from PTSD could benefit from interventions, he said. If PTSD goes unaddressed, the condition can lead to more severe problems, he said.

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