After serving four years as a Marine including two deployments to Iraq, Brian Scott Ostrom, now 27, returned home to the U.S. in 2007 with a severe case of post-traumatic stress disorder. “The most important part of my life already happened. The most devastating. The chance to come home in a box. Nothing is ever going to compare to what I’ve done, so I’m struggling to be at peace with that,” Scott said.

Craig F. Walker / The Denver Post

Brian Scott Ostrom cups his hand over his mouth as he tries to calm a panic attack at his apartment in Boulder, Colo., May 2011.

Ostrom attributes his PTSD to his second deployment to Iraq, where he served seven months in Fallujah with the 2nd Reconnaissance Battalion. “It was the most brutal time of my life,” he said. “I didn’t realize it because I was living it. It was a part of me.”

Craig F. Walker / The Denver Post

Ostrom counts the stitches in his wrist while having a drink at a bar in Boulder, April 2011. He attempted suicide earlier in the week after he and his girlfriend had an argument. He said many times he should have died overseas, and during the fight with his girlfriend, she agreed.

Craig F. Walker / The Denver Post

Ostrom reacts to his apartment application being turned down in Westminster, Colo., May 2011. The leasing manager said he was sorry but couldn't allow him to move in because of an assault charge on his background check.

Since his discharge, Ostrom has struggled with daily life, from finding and keeping employment to getting an apartment to maintaining healthy relationships. But most of all, he’s struggled to overcome his brutal and haunting memories of Iraq.

Craig F. Walker / The Denver Post

A picture showing Ostrom holding his little brother after graduating boot camp at Paris Island, S.C., in June 2003 hangs on the refrigerator at Scott's new apartment in Broomfield, Colo., May 2011.

Craig F. Walker / The Denver Post

Ostram shakes hands and talks with fellow veteran Mike Butler at a restaurant in Broomfield on Veterans Day. Veterans drank for free, and Scott was happy to find someone to talk with.

Nearly five years later, Ostrom remains conflicted by the war. Though he is proud of his service and cares greatly for his fellow Marines, he still carries guilt for things he did — and didn’t do — fighting a war he no longer believes in.

Editor's note: Msnbc.com took note of this exceptional photo story done by Denver Post Pulitzer Prize winning photographer Craig F. Walker because of its intimate, in-depth look at living with PTSD.  You can see many more of Walker's images, view video and read more about Scott Ostrom's story at the Denver Post website.

Related Content:

• When the war comes home - From combat in Afghanistan to their return home to Ft. Drum in upstate New York, photojournalist Erin Trieb profiles one group of soldier’s battle with PTSD.
•  Ian Fisher: American Soldier - From high school to boot camp, photojournalist Craig F. Walker earned a Pulitzer Prize for his in-depth look at one Colorado teen's decision to enter the military.

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