A total of 16 people were wounded in the shooting rampage at Fort Hood in Killeen Wednesday. Their conditions range from stable to critical. Four people were killed, including the shooter, 34-year old Army Specialist Ivan Lopez.

Lopez served in Iraq and moved to Fort Hood just a few months ago from Fort Bliss. According to investigators, he had no record of violence, but showed signs of emotional distress. He was also being evaluated for post-traumatic stress disorder, or PTSD.

"He was undergoing a variety of treatment and diagnoses for mental health conditions, ranging from depression to anxiety," U.S. Army Secretary John McHugh said.

PTSD is something that affects many serviceman and women when they return home from a war zone. It can often be a debilitating condition. On Thursday, Kiii News Reporter Michael Gibson spoke with one local veteran who has been diagnosed with PTSD, and is working to help others.

Philip Davila is going to college to become a teacher. He also works part-time at the Nueces County Veteran's Center, a place where he oftentimes is able to help fellow veterans get the medical care they need when it comes to PTSD.

Davila knows something about that, because he's suffering from the psychiatric disorder himself.

"I understand PTSD and the severity, and how it can push a person overboard," Davila said. "Because we're taught from day one how to survive -- how to go from zero to 100 at the first gun shot, and they want us to just turn it off when we come home, and you just can't do that."

Davila joined the U.S. Navy in 2004. He was a corpsman and served in Iraq and Afghanistan with the 2nd Battalion 8th Marines. In that infantry unit, he worked to not only save lives, but was often armed and in the middle of constant battles with the Taliban.

He said he was taught to be hyper vigilant because he could end up being under fire at any time of the day or night. That training stays with him to this day.

"There's certain things that set me off," Davila said. "Congestion. Lots of people around me anytime I walk into new areas. I've got to check the exits. I've got to look for my choke points, my sniper nests. Trash on the roads is a big one. Just trash in parking lots around a lot of vehicles."

The trash is a problem because he said the Taliban would place bombs in the trash, or even in dead animals. So even simple things he may see or hear can trigger a much different reaction in him than the rest of us.

However, Davila said he usually recognizes the signs of stress and goes to a quiet place to calm down. As far as treatment, he does speak with a doctor from time to time. He said that veterans have to wait sometimes to get treatment, and he wishes that wasn't the case.

Still, Davila urges all vets to get help, because as he found out, PTSD is a real disorder and something he may live with for the rest of his life.