We’ve all seen this film before: the grainy black-and-white shot with a crosshair on top. Dark blobs moving across the screen. Then, a pause, an explosion and dust. A few moments later you can make out the bodies. Sometimes you’ll see the injured, dragging themselves out of the wreckage.

Whatever your take on drone warfare, watching video of a strike is an upsetting experience. Now a documentary, National Bird, seeks to describe the traumatic effect that planning and executing these strikes has had on some military personnel.

Director Sonia Kennebeck’s first feature, National Bird brings us character studies of three former United States air force personnel, Lisa, Daniel and Heather, who wanted to share their experience of seeing people die, live. Executive produced by Wim Wenders and Errol Morris, and following on from the 2014 documentary, Drone, Kennebeck’s film explores how fighting a mechanised, remote war from a trailer in Nevada has affected her subjects. Lisa travels to Afghanistan to meet a family who lost children to an airstrike. Daniel has become an anti-war campaigner. Heather, a former drone imagery analyst, is diagnosed with post-traumatic stress disorder, and becomes the first veteran from the drone programme to receive state support for her treatment.

Kabul graffiti in a still from National Bird. Photograph: Torsten Lapp © Ten Forward Films

“They talk about how difficult it is to be in the US and be deployed and fighting, while still being at home in safety,” says Kennebeck. “I think the human mind has an issue dealing with that, because you go into this secret environment and you’re in a real warzone: you’re killing people. Then you go home and sit at the dinner table with your family. It’s schizophrenic in a way, to work like that. Your family doesn’t have a clue and you’re not allowed to talk to them about your experiences.”

Much of the detail of the US military’s drone programme is classified. During National Bird’s filming, the FBI raided Daniel’s home and searched for secret documents with a view to making him the 13th American ever to be charged with espionage. He’s one of the clients represented by Jesselyn Radack, a former ethics advisor to the US Department of Justice who appears in the film and now works as an attorney, often defending whistleblowers. Edward Snowden is also a client.

The term PTSD was originally associated with ground troops who had survived the Vietnam war. Because of this there is still some debate over whether drone operators and analysts do suffer PTSD in a traditional sense, but it’s clear that part of the problem in analysing any effect that drone warfare is having on servicemen and women is the secrecy around the programme. Demand for drone teams is soaring across all branches of the US military, yet, according to leaked documents, USAF drone pilots are quitting in record numbers.

“They’re having such a high burnout rate in the air force that they’re outsourcing it to private contractors,” says Radack. “Then there’s no way to keep track of them, as they’re not subject to freedom-of-information requests.”

A US neighbourhood seen from a drone in National Bird. Photograph: Torsten Lapp © Ten Forward Films

Heather, who has written for the Guardian on the euphemisms used to hide the true nature of modern war, brings National Bird a furious energy. The language of this new war – “surgical strike”, “precision kill” – infuriates her. They are political terms, part of a military lexicon that defines anyone killed in an attack (even those not targeted) as “enemies killed in action”, until posthumous evidence proves otherwise. The idea that drone strikes are precise is ridiculous, she says. The figures bear her opinion out. One leak revealed that in one operation nearly 90% of people killed were not the intended targets.

“I think the PTSD stems from being part of this dirty work,” says Radack. “There’s a lot of addiction issues, a lot of depression. My guys talk about drunk droning [akin to drunk driving], sniffing bath salts [US slang for various designer drugs] because they won’t be detected on drugs tests. They have to anaesthetise themselves in order to be able to do this.

“I asked them how many people in the trailer had addiction problems and they said: ‘Everybody. We had three domestic violence problems, we had two drink-driving problems, six people were alcoholics.’ And we’re talking about a group of 12 people in one trailer. And it’s typical, because you hear the same stories from clients in different trailers in different places. It’s the same story. Total dysfunction.”

In National Bird, Heather says three of her former colleagues have committed suicide. Psychiatric treatment for drone operators and analysts is not always readily available, partly because most therapists don’t have the security clearance necessary to talk to their patients about the job. Heather is, in a sense, at the vanguard of post-combat treatment, in that hers is an old condition stemming from a new type of war.

National Bird includes its own drone footage, a re-creation of the killing of more than a dozen innocent people by drone operatives who mistook them for insurgents. In the film, the pilot and the operating crew are voiced by actors. If they sound a little unconvincing, it’s partly because we are now worryingly familiar with the real thing.