By Pat McGonigle
St. Louis (KSDK) -- If you see Dave "Moose" McArthur around town, or at one of his father's area bakeries, chances are, he'll be smiling. But behind closed doors, it's a different story.
"When I'm not smiling, I'm angry. I'm crying. I'm lost," McArthur says.
Moose was a standout football player at Fox High School.
He could have played at the college level.
But this Arnold, Missouri native always dreamed of becoming a US Marine.
"It's kind of like something you're born to do. You know, like my whole life I was playing military, in my yard and with my friends," McArthur says with a wide smile. "I was gung ho. I had my car covered with Marine stickers."
But in May of 2010 , Lance Corporal Dave McArthur's dream of military service turned into a nightmare. His armored vehicle went over a roadside bomb in Afghanistan. McArthur walked away from the explosion without any injuries-that you could see.
"I was told to sleep on it. Told to go to sleep. You know, if you have a concussion you don't go to sleep. But, we were told to sleep on it," McArthur recalls.
It wasn't until months of sleepless nights later that doctors discovered Moose McArthur suffered a traumatic brain injury from the explosion.
After looking at high resolution scans of McArthur's brain, doctors decided "one more blast will kill him".
McArthur is far from alone.
The US Department of Defense is funding a $5.3 million study on traumatic brain injuries at Saint Louis University.
"A term that's been out there, in the media and in the literature, is 'invisible injuries'," said Dr. Tyler Roskos, one of the lead SLU researchers.
Last week, the Department of Defense extended the study for another year.
"If we can better identify what's wrong, what's not working properly in the brain, we can then tailor our treatments to address those problems more carefully and more closely," Roskos said.
In the meantime, the 22-year-old combat veteran continues the battle at home. He's a married man with a daughter and a second baby on the way.
Even so, Moose often slips into a deep depression.
"I'm not suicidal, I don't have suicidal plans, but a lot of times, I'll go to bed and pray that I don't wake up," said McArthur.
Moose can't work because of his injuries, but he has no regrets.
His purple heart license plate tells his story: OEF-TBI. Operation Enduring Freedom. Traumatic Brain Injury.
"I'd do it all over again. Even the injury, the experience, I'd do it all over again," said Moose.
On Saturday you're invited to a ceremony to honor veterans like Dave McArthur. It's from 10 a.m. to 11:30 a.m. at the Four Seasons shopping plaza on Olive Boulevard and Woods Mill Road in Chesterfield.
The Knights of Columbus are also hosting a barbecue at the same location from 11 am until 7 pm on Friday and Saturday.
Saint Louis University is also looking for volunteers to further its research into traumatic brain injuries. If you'd like to learn more, you can call 314-977-8560 or go to www.slu.edu/tbi.