Right. That's an excellent question.
Really, it comes down to a comparison of the impact of service dogs—psychiatric service dogs, in this case—versus emotional support dogs. The therapy dogs can be present during treatment, but they're not something that the veteran would have with him at all times. It comes down to those two categories, service dogs and emotional support dogs.
That was the main focus of the United States Veterans Affairs study. They paired 88 veterans with a service dog, and 65 veterans with an emotional support dog. That's the number of people who completed the study. It was a two-year study. What they found was that emotional support dogs showed similar impacts when compared to service dogs when measuring sleep quality, depression levels and mental aspects of the quality of life. However, they found specifically that psychiatric service dogs had a much greater impact in terms of improvement in PTSD symptoms and anger reaction, and to some extent in suicidality, compared to those with emotional support dogs.
Those are the findings of the study that were just released in the past couple of months.