A medic helps a Palestinian in the Shejaia neighborhood, which was heavily shelled by Israel during fighting, in Gaza City, July 20, 2014. (Finbarr O’Reilly/Reuters)

A dust storm blows through Outpost Kunjak, in Southern Afghanistan’s Helmand Province, October 28, 2010. (Finbarr O’Reilly/Reuters)

I wish I could pinpoint a defining moment, or a shutter click that marked the instant when I’d had enough of covering war. But I can’t. Maybe there was one hidden amid the dust and rubble and broken bodies I’d left behind when I walked out of Gaza after the 2014 war there. But rather than a sudden change of heart, my appetite for covering conflict faded gradually, a light waning until there was nothing left to see.

The conflicts and crises I’d covered over 15 years — in Congo, Sudan, Chad, Afghanistan, Libya and elsewhere — began to merge into an unending blur. I grew increasingly uncomfortable with photographing people at their most vulnerable while being able to do little to help. And my sense of purpose wavered as friends and colleagues were injured and killed on the job. In the end, I burned out.

Since stepping back from the front lines, I’ve spent the past two years collaborating on a book, “Shooting Ghosts,” with former U.S. Marine Corps sergeant Thomas James Brennan. I met Brennan at a remote outpost in Afghanistan in 2010 while embedded with his squad. We were out on a patrol when an explosion from a rocket-propelled grenade wounded him during a Taliban ambush. He survived, and we remained in touch after returning home. And just as I was grappling with the emotional fallout from various wars, Brennan, a veteran of both Iraq and Afghanistan, was struggling with post-traumatic stress, a traumatic brain injury from the explosion, and the moral implications of having killed during combat.

Although typically resilient, journalists who cover conflict experience rates of post-traumatic stress and depression up to five times higher than the general population, and at rates similar to combat veterans (about one in four, according to experts).

We didn’t want to write a book that glorifies war. “Shooting Ghosts” is about how and why war changes people, and what happened as we came to terms with the things we’ve seen and done. Trauma untethers us from a world that was once familiar. After war, we struggled to find again the purpose, the bonds and — in truth — a weird kind of love that exists on the battlefield. We drifted and came undone. The journey back was a lonely one, but we couldn’t have made it alone. Friendship, family, and a sense of belonging helped us find our way again.

Brennan has turned to investigative journalism and earlier this year broke the Marines United nude photo-sharing scandal, prompting Pentagon and congressional inquiries that have changed codes of conduct across the military.

I’ve turned my focus toward mentoring, writing and photographing personal projects. I’ve returned the last two years to Senegal, where I was based for eight years as a Reuters photographer covering Africa, to document the visual splendor of Dakar Fashion Week. There, amid the models and make-up and music, I’ve rediscovered the joy of creating pictures far from the destructive forces of war.

Sgt. Thomas James Brennan smokes a cigarette in his bunk surrounded by photographs of his wife Melinda and their daughter Madison, 2, after a night of rain at the remote outpost of Kunjak in southern Afghanistan’s Helmand province, October 29, 2010. (Finbarr O’Reilly/Reuters)

A Canadian soldier from the NATO-led coalition (C) moves under fire as an Afghan machine gunner shoots his weapon after their position was hit by Taliban shells during an ambush in Zhari district of Kandahar province, southern Afghanistan, October 23, 2007. (Finbarr O’Reilly/Reuters)

A wounded Canadian soldier from the NATO-led coalition crawls for cover seconds after his position was hit by a Taliban shell during an ambush in Zhari district of Kandahar province, southern Afghanistan, October 23, 2007. (Finbarr O’Reilly/Reuters)

A prisoner screams while being beaten by government troops just outside Goma in eastern Congo, November 23, 2008. (Finbarr O’Reilly/Reuters)

A mother and child at a feeding center in Tahoua, Niger, August 1, 2005. (Finbarr O’Reilly/Reuters)

Designer Oumar Dicko of Mali and Belgium, laces up a model in one of his creations backstage during Dakar Fashion Week in the Senegalese capital, Saturday July 1, 2017. (Photo by Finbarr O’Reilly)

Model Nafissatou Gningue waits backstage during Dakar Fashion Week, June 5, 2016. (Finbarr O’Reilly)

Finbarr photographing Congolese government soldiers along the front line near Goma, November 12, 2008, (Marcus Bleasdale)

Finbarr O’Reilly is co-author with Thomas James Brennan of “Shooting Ghosts, A US Marine, a Combat Photographer and their Journey Back From War,” published today by Viking. Follow him on Instagram and Twitter

More In Sight:

In service to the magic of the devious, a visual ode to the punks of San Francisco

‘He is being pressured to find a wife and his need to rent a girlfriend is real’

A photographer hung out with the KKK in Tennessee and Maryland. Here’s what he saw.

About In Sight:

In Sight is The Washington Post photography blog for visual narrative. This platform showcases compelling and diverse imagery from staff and freelance photographers, news agencies and archives. If you are interested in submitting a story to In Sight, please complete this form.