U.S. Air Force/Master Sgt. Steve Horton
Capt. Richard Koll, left, and Airman First Class Mike Eulo monitored a drone aircraft after launching it in Iraq.
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.
But Air Force officials and independent experts have suggested several potential causes, among them witnessing combat violence on live video feeds, working in isolation or under inflexible shift hours, juggling the simultaneous demands of home life with combat operations and dealing with intense stress because of crew shortages.
“Remotely piloted aircraft pilots may stare at the same piece of ground for days,” said Jean Lin Otto, an epidemiologist who was a co-author of the study. “They witness the carnage. Manned aircraft pilots don’t do that. They get out of there as soon as possible.”
Dr. Otto said she had begun the study expecting that drone pilots would actually have a higher rate of mental health problems because of the unique pressures of their job.
Since 2008, the number of pilots of remotely piloted aircraft — the Air Force’s preferred term for drones — has grown fourfold, to nearly 1,300. The Air Force is now training more pilots for its drones than for its fighter jets and bombers combined. And by 2015, it expects to have more drone pilots than bomber pilots, although fighter pilots will remain a larger group.
Those figures do not include drones operated by the C.I.A. in counterterrorism operations over Pakistan, Yemen and other countries.
The Pentagon has begun taking steps to keep pace with the rapid expansion of drone operations. It recently created a new medal to honor troops involved in both drone warfare and cyberwarfare. And the Air Force has expanded access to chaplains and therapists for drone operators, said Col. William M. Tart, who commanded remotely piloted aircraft crews at Creech Air Force Base in Nevada.
The Air Force has also conducted research into the health issues of drone crew members. In a 2011 survey of nearly 840 drone operators, it found that 46 percent of Reaper and Predator pilots, and 48 percent of Global Hawk sensor operators, reported “high operational stress.” Those crews cited long hours and frequent shift changes as major causes.
That study found the stress among drone operators to be much higher than that reported by Air Force members in logistics or support jobs. But it did not compare the stress levels of the drone operators with those of traditional pilots.
The new study looked at the electronic health records of 709 drone pilots and 5,256 manned aircraft pilots between October 2003 and December 2011. Those records included information about clinical diagnoses by medical professionals and not just self-reported symptoms.
After analyzing diagnosis and treatment records, the researchers initially found that the drone pilots had higher incidence rates for 12 conditions, including anxiety disorder, depressive disorder, post-traumatic stress disorder, substance abuse and suicidal ideation.
But after the data were adjusted for age, number of deployments, time in service and history of previous mental health problems, the rates were similar, said Dr. Otto, who was scheduled to present her findings in Arizona on Saturday at a conference of the American College of Preventive Medicine.
The study also found that the incidence rates of mental heath problems among drone pilots spiked in 2009. Dr. Otto speculated that the increase might have been the result of intense pressure on pilots during the Iraq surge in the preceding years.
The study found that pilots of both manned and unmanned aircraft had lower rates of mental health problems than other Air Force personnel. But Dr. Otto conceded that her study might underestimate problems among both manned and unmanned aircraft pilots, who may feel pressure not to report mental health symptoms to doctors out of fears that they will be grounded.
She said she planned to conduct two follow-up studies: one that tries to compensate for possible underreporting of mental health problems by pilots and another that analyzes mental health issues among sensor operators, who control drone cameras while sitting next to the pilots.
“The increasing use of remotely piloted aircraft for war fighting as well as humanitarian relief should prompt increased surveillance,” she said.
