In the first study of its kind, researchers with the Defense Department have found that pilots of drone aircraft experience mental health problems like depression, anxiety and post-traumatic stress at the same rate as pilots of manned aircraft who are deployed to Iraq or Afghanistan.

The study affirms a growing body of research finding health hazards even for those piloting machines from bases far from actual combat zones.

“Though it might be thousands of miles from the battlefield, this work still involves tough stressors and has tough consequences for those crews,” said Peter W. Singer, a scholar at the Brookings Institution who has written extensively about drones. He was not involved in the new research.

That study, by the Armed Forces Health Surveillance Center, which analyzes health trends among military personnel, did not try to explain the sources of mental health problems among drone pilots.