The two men who targeted and murdered law enforcement officers in Dallas and Baton Rouge had at least one other thing in common: both had been members of the military deployed to the Middle East, service that has sent thousands of men and women home with post-traumatic stress and other mental health issues, including anger and aggression.

It is unknown if Micah Johnson and Gavin Long experienced post-traumatic stress symptoms or other difficulties adjusting to life as civilians, or if their experiences in Iraq and Afghanistan contributed to a violent mindset.

But PTSD is “one of the signature injuries of the U.S. conflicts in Afghanistan and Iraq,” concluded two National Academy of Science reports published in 2012 and 2013. As many as 20% of veterans of these wars have PTSD, researchers found. They cautioned the numbers may be an underestimate as they don’t account for people who don’t seek help because of stigma or whose symptoms don’t meet the threshold for diagnosis but still interfere with everyday life.

Irritable behavior, angry outbursts and reckless or self-destructive behavior are hallmarks of PTSD, according to the Diagnostic and Statistical Manual, which catalogues psychiatric illnesses, and studies have shown a clear link between combat deployments and problems with anger and physically aggressive behavior back home.

The safety net that awaits military veterans when they get home is also stretched and frayed.

The National Academies reports, as well as an Inspector General’s report about access to mental health care at the Veterans Affairs, chronicle an agency with many programs to address PTSD, but almost no tracking to determine which are effective, treatments that vary widely depending on which therapist or doctor one happens to see, and long waits for evaluation and treatment.

“The committee has serious misgivings about inadequate and untimely clinical follow-up and low rates of delivery of evidence-based treatments, especially therapies to treat PTSD, depression, and substance use disorder,” the report said.

“It is so easy to fall through the cracks,” said Mike McMichael, who deployed to Iraq several times between 2003 and 2005 as part of the North Carolina Army National Guard.

When McMichael was coming home, he filled out a PTSD screening checklist. “‘Did you see dead bodies?’” he recalls it asking. “Check. ‘Did you see dead soldiers?’ Check. ‘Did you see dead civilians?’ Check. ‘Did you see dead children?’ Check. If you said yes to any one of those you’re supposed to sit down with a counselor or chaplain. I said yes to every single one of them.” Yet he was never sent for a mental health evaluation. McMichael lost a string of jobs, contemplated suicide, and almost got divorced before he finally sought help, he said, and has since founded an organization called Outside the Wire to help veterans like him. “Our VA system is just overwhelmed,” he said.

The report also found that unemployment and underemployment are “acute problems for military veterans,” many of whom began returning home just as the 2008 recession hit.

“In the United States we valorize our vets with words and posters and signs, but we don’t give the what’s really important to Americans…jobs,” anthropologist Sharon Abramowitz told journalist Sebastian Junger for his new book, Tribe: On Homecoming and Belonging. “All the praise in the world doesn’t mean anything if you’re not recognized by society as someone who can contribute valuable labor.”

Junger identifies a sense of alienation among soldiers who leave the battlefield — where they sleep “shoulder-to-shoulder with other people that you would die for” — and arrive home to carpools, nuclear families, and individualism. This transition can lead to a sort of existential crisis that is often mistaken for PTSD, Junger argues.

What little is known about Johnson, who shot at police officers, sniper-style, during a Dallas protest on July 7, seems to indicate he suffered many of these issues.

Click here to read the full story at The Marshall Project.