"Not all wounds are visible," he said. "That's how I explain it to people."
Hernandez received a service dog in 2010 through Project HEAL, part of ECAD, an organization that trains and breeds assistance dogs. Project HEAL sets up veterans with PTSD with service dogs. Hernandez still volunteers with Project HEAL.
"He knows if something is wrong, and I can't figure it out," Hernandez said of Valor. "The dog has the extra Spider-Man sense." Hernandez still takes medication for PTSD.
Paul Aragon, a 29-year-old retired veteran, also has PTSD, but his only treatment is his service dog. Aragon got his service dog, Zoey, in October after his medication stopped working. Zoey "keeps me calm," he says.
Aragon, who studies motorcycle mechanics at Universal Technical Institute in Orlando, takes Zoey everywhere: dinner, movies, plane trips, even sometimes to school.
But not everyone recognizes the dogs as legitimate. Hernandez and Aragon have had incidents where people have questioned their bringing a dog into a public place. Hernandez even filed a lawsuit last year, alleging that he was kicked out of a fast-food restaurant because of his dog. It was later settled out of court.
The legal side
Part of the reason that psychiatric service dogs present a tricky situation is that different federal agencies implement different regulations with respect to them.
The Department of Justice, in its guidelines for implementing the Americans with Disabilities Act, defines "service animals" as "dogs that are individually trained to do work or perform tasks for people with disabilities." This can include "alerting and protecting a person who is having a seizure, reminding a person with mental illness to take prescribed medications, calming a person with Post Traumatic Stress Disorder (PTSD) during an anxiety attack, or performing other duties."
The guidelines state that dogs whose "sole function is to provide comfort or emotional support do not qualify as service animals under the ADA."
But service animals are required to be allowed in establishments that sell or prepare food, for example. And "allergies and fear of dogs are not valid reasons for denying access or refusing service to people using service animals," according to the guidelines.
In a situation such as a school classroom or a homeless shelter, the allergic person and the person with the service dog should be assigned to different locations if possible, the guidelines say.
The Department of Transportation, on the other hand, makes reference to animals that "assist persons with disabilities by providing emotional support." Its guidelines allow airlines to require documentation of a person's disability and say that the medical necessity of having the animal while traveling is understood.
The Department of Housing and Urban Development talks about assistance animals, which can include "providing emotional support to persons who have a disability related need for such support."
There's room for fraud and shady maneuvering here, Ensminger said. There have been cases where patients have written their own letters that psychiatrists have signed to recommend certifying a psychiatric dog. That's not how prescribing a treatment is supposed to work. There are also fake certification websites, Herzog said.
And it's not just a letter that turns a dog into a psychiatric service dog. There's a rigorous training procedure, and the whole process can cost as much as $38,000, Ensminger estimates.
Although some people try to train dogs themselves, this approach often fails because it takes a lot of expertise to choose the right dog, train it, and develop a relationship between a person and a service dog, said Darcie Boltz, executive director of Heeling Allies.
It takes a dog with a unique temperament to be properly suited for this work, and there can be animal welfare issues when improperly selected or trained dogs become mental health service dogs, Boltz said.
Although the system for psychiatric service dogs and emotional support animals can be abused, Lieberman says it's rare.
"If it isn't really important to you psychologically, there's so much hassle that you have to go through, you wouldn't necessarily ask for it," she said. "The solace of having your dog there to comfort you needs to be more important than the hassle you have to go through."