Until recently, Sgt. Bill Campbell's horrifying memories from his tour of duty in Iraq left him unable to leave his house.
Constantly fearing he would be attacked from behind — a paranoia stemming from his violent tour of duty — Campbell says his post traumatic stress disorder symptoms made everyday life virtually unbearable.
That is, until he met Pax, a now 17-month-old yellow Labrador, specially trained to help him cope with PTSD, doing everything from reminding him to take his medication to coaxing him out of his house.
"Pax forces me to go out," Campbell told ABCNEWS.com. "He has to go for walks."
Pax was donated to Campbell by the N.Y.-based non-profit organization Puppies Behind Bars, an organization that has provided service dogs to individuals with disabilities since 1997, but just recently expanded their program to include war veterans, too.
And when Campbell, 46, returned from Iraq in 2005, help was exactly what he needed. In addition to being diagnosed with PTSD, car bombs had sprayed shrapnel in his hand and head, causing nerve damage and traumatic brain injury.
"I have anxiety, depression and really exaggerated start response," said Campbell, who spent several weeks in a veteran's hospital near his hometown in Shelton, Wash., about 60 miles west of Seattle. "And memory problems."
Pax, who is the first dog to be deployed by Puppies Behind Bar's new initiative "Dog Tags: Service Dogs for Those Who've Served Us," knows more than 50 different commands. He warns Campbell of strangers or possible dangers, clears crowded areas and provides a reality check when Campbell gets lost in hallucinations or nightmares.
"It does help that he can protect my back," said Campbell, of Pax's training to always keep an eye on his back. "If I go places and tell him to sit, he faces the opposite direction and it's comforting."
"Pax will lie down, and if someone is coming up from behind me, he'll sit up and warn me," said Campbell. "Then I'll know someone's coming."
Puppies Behind Bars incurs all the costs of Pax's care, said company president and founder Gloria Gilbert Stoga, who told ABCNEWS.com that two more veterans are slated to get dogs this coming May.
Costs include the extensive training that the puppies receive, said Stoga, who receives the puppies when they are 12 weeks old and then places them with inmates at seven different prisons.
Both the inmates and the puppies learn discipline through the arrangement, and after about a year and a half, the dogs graduate to what Stoga refers to as "dog finishing school," which includes taking the dogs to get "socialized" at West Point, where they are able to interact with injured soldiers.
"The inmates love it, a number of the men are veterans themselves, and they absolutely love that they're doing something to help a fellow service member," said Stoga. "And several of the women in prison suffer from depression of PTSD and appreciate the difference the dog will be able to make to someone who is suffering."
According to Marty Becker, a veterinarian and author of "The Healing Power of Pets," people often underestimate the unique power dogs have to help individuals heal, even from the most severe injuries.