Talking it out is usually the best therapy. And reaching out to others often is a signal that you're on your way out of the darkness.

So say mental health experts who work with those who've experienced terrible things that continue to haunt them in myriad ways.

According to the National Center for PTSD, an arm of the U.S. Department of Veterans Affairs, between 11 and 20 percent of military veterans since the Vietnam War are living with post-traumatic stress disorder. Including the man who calls himself "The Real Forrest Gump."

Our Eric Peterson covered a visit to St. Viator High School in Arlington Heights by retired Army Sgt. Sammy L. Davis, which was a prelude to Veterans Day on Saturday. Davis, whose Vietnam War heroism parallels that of the fictional Tom Hanks character, actually was awarded the Medal of Honor in 1968 by President Lyndon Johnson. Footage from that ceremony was used in the 1994 film. But Davis' life beyond Vietnam is quite a different story.

The students were shown a video that described how the severely wounded Davis rescued three wounded American soldiers during a battle with the Viet Cong. Davis told students that as a result of that battle, he's suffered post-traumatic stress.

It was Gen. William Westmoreland, the commander of U.S. forces in Vietnam, who urged Davis to speak about his experiences. And speak about them he does. It's a form of therapy for him. When a sophomore at the school thanked Davis for showing her how successful and honored a fellow PTSD sufferer could be, he responded, "That could very well be the reason I was able to make it here today."

That exchange should resonate with us all. It takes courage to talk about your nightmares. But in doing so, you might help others as well as yourself. Just last year, Davis and his wife traveled to Vietnam, where they met with a group of people who fought on the other side. They discussed how neither had felt hatred toward the other -- that they were doing what their nations expected of them. Davis left Vietnam this time having taken another step toward recovery.

Not everyone with PTSD has a 4-star general looking after them or a platform like Davis does. Many people who suffer with PTSD do so quietly. What's in their heads and hearts often is hard to hear, but it is so much harder for them to bear alone. If you know people with PTSD, talk to them. Gently ask about their experiences.

And listen.

Above all, listen.