Airman Mena also returned from war a drastically changed man.

He had deployed to Iraq in 2005 but saw little action and wanted to go back. He got the chance in late 2006, when sectarian violence was hitting a peak.

After coming home, he spoke repeatedly of feeling guilty about missing patrols where a sergeant was killed and where several platoon mates were seriously wounded. Had he been driving on those missions, he told therapists, he would have avoided the attacks.

“On my first day, I saw a total of 12 bodies,” he said in one psychological assessment. “Over there, I lost faith in God, because how can God allow all these dead bodies?”

By the summer of 2008, he was on half a dozen medications for depression, anxiety, insomnia and pain. His back and neck pain worsened, but Air Force doctors could not pinpoint a cause. Once gregarious and carefree, Airman Mena had become perpetually irritable. At times he seemed to have hallucinations, his mother and friends said, and was often full of rage while driving.

In February 2009, he received an honorable discharge and was given a 100 percent disability rating by the Department of Veterans Affairs, meaning he was considered unable to work. He abandoned plans to become a police officer.

Now a veteran, his steady medication regimen continued  but did not seem to make him better. His mother, Pat Mena, recalls him being unable to sleep yet also listless, his face a constant shade of pale. Shocked by the piles of pills in his Albuquerque apartment, she once flushed dozens of old prescriptions down the toilet.

Yet for all his troubles, he seemed hopeful when she visited him in early July 2009. He was making plans to open a cigar store, which he planned to call Fumar. His mother would be in charge of decorating it.