
Veterans and their service dogs —
Many U.S. veterans are struggling with invisible wounds such as post-traumatic stress disorder, anxiety and depression. But some of them are finding peace at home thanks to their canine companions. Click through the gallery to meet a few veterans and the service dogs who help them get through their daily lives.

Jeff Wilson and Lobo —
Lobo helps Jeff Wilson keep cool in public places. Wilson doesn't like being startled, so with a simple "watch my back" command, the border collie-German shepherd mix watches Wilson's 6 o'clock and gives him a little nudge if anyone walks up behind him at the grocery story or other public setting. If Wilson's anxiety kicks in, Lobo will jump and put his paws on Wilson's chest to give him something else to focus on.

Ana Sarver and Vito —
Before she met Vito, Ana Sarver would average about two hours of sleep a night. Like many veterans with PTSD, she would struggle with restlessness, nightmares and hypervigilance. With Vito, "as soon as he feels me restless, he wakes up and he wakes me up and brings me out of it. ... He keeps me from getting up in the middle of the night and pacing every which way." Vito also gives Sarver the ability to function during the day. With the dog at her side, Sarver feels more comfortable in social settings such as restaurants.

David Angel Leos and Shadow —
David Angel Leos returned from his second tour in Iraq and found his life falling apart: "I was drinking, family life was really tough. Nightmares, constantly. Flashbacks." He had lost many of his close friends in the war, and he was struggling with extreme PTSD. But after being matched up with Shadow, he has been able to find some peace. "Having him is like having a battle buddy with you, somebody who is going to watch your back -- knowing if you don't see it, he will."

James McQuoid and Iggie —
A trip to the grocery store used to send James McQuoid into a panic. When the Iraq War veteran heard a child crying, he remembered kids screaming in Falluja. Coins jingling in the register reminded him of ammunition carried around a soldier's neck. But Iggie calms McQuoid in public places, creating space between McQuoid and others. He also wakes McQuoid from nightmares and keeps his overall anxiety level down. "Without Iggie, I would still be in my house ... probably divorced from my wife and very estranged from my son," McQuoid said.

Jeremiah Gaches and Rocky —
When Jeremiah Gaches came back to the United States, he isolated himself a lot. But after he met Rocky, Gaches found it much easier to get out of the house. Rocky watches Gaches' surroundings so the veteran doesn't always have to be at high alert, and if Gaches is feeling uncomfortable, Rocky will calm him down. Now, Gaches said, he's comfortable talking to people in public, and he's helping to train other veterans and their service dogs.

Jennifer Haeffner and Shadow —
Shadow is the only reason Jennifer Haeffner goes out in public these days. Before she and the Labrador-Burmese mountain dog teamed up, she essentially had been housebound for five years, considering herself lucky if she got out once a month for grocery shopping. Now, she and Shadow go out several times a week, and he wakes her up from nightmares and picks things up so she doesn't stress her bad back and hips.

Nick Udall and Annie —
When Nick Udall returned from Vietnam, he found it very difficult to be in a crowd. He was always on alert, looking for exit strategies "if something happens." Annie is vigilant so he doesn't always have to be. She also helps remind him to take his medicine, running up to his chest and sticking her nose in his face. "I take anti-anxiety medicine, but I get the same effect by holding her," he said. "The reason I hold her up here like this is as soon as I do just -- whoosh -- I can feel the stress go away. It's amazing."

