"You can also use them as an excuse to get out of things or leave early," Hudson said.
Case in point
Shadow is one pooch accustomed to being used for such occasions.
The 2-year-old Labrador-Bernese mountain dog mix is the inseparable pal of Jennifer Haeffner, a seven-year Army veteran who had been housebound for about five years before meeting Shadow in the summer.
"He's a very active dog. It makes me do things. I don't have the option of hiding in the house. I have to go out," said the 41-year-old Ripon, California, resident.
During Operation Desert Storm, where she served for about nine months between 1991 and 1992, she was sexually assaulted on multiple occasions by other service members, she said. It's a fairly common occurrence that befalls about one in four women in the military, according to the VA.
It left her feeling alone in the world. She wanted to disappear. She forgot how to deal with people and eventually became a recluse, considering it a "good month" if she got out just once to shop for groceries.
She didn't attend any of her large family's gatherings. Too many people and too much noise, she said. It terrified her.
"For years after that, I would go out and wander the streets late at night, just hoping someone would kill me because I wasn't brave enough to kill myself," she said.
About five months ago, her therapist recommended that she meet Cortani.
Cortani recalls Haeffner wouldn't look her in the eye when they met. Her leg bounced when she spoke, and she pressed her fingernails into her arm. Her boyfriend was constantly by her side.
"You could just tell the pain and the anguish that even meeting me for the first time was causing," said Cortani, an Army veteran herself.
Operation Freedom Paws teaches participants to train their own dogs, to customize their behavior. First, the dogs learn to sit, then heel -- the basic stuff.
Shadow now knows how to pick things up for Haeffner so she doesn't put stress on her bad back and hips. He acts as a barrier, physically putting himself between her and any new people she meets.
When she wakes up feeling gloomy, he lets her stay in bed and pet him until she's ready to face the day. If she hears a sound during the night, he stays by her side as she checks it out, and Shadow is quick to snap her out of nightmares.
"He'll breathe on me or lay his head across mine to wake me up," she said of her 55-pound companion. "If I'm in a bad mood, he'll come over and insist I play with his toy or lay his lead in my lap or lick my feet -- cheer me up."
Cortani said the difference between the Haeffner of five months ago and the Haeffner of today is like "night and day."
She builds friendships. She's been to the aquarium. She's gone horseback riding. She goes places without her boyfriend.
"She's creating her own new normal," Cortani said.
Added Haeffner: "I'm much better now. I'm happier."