The couple were dealing with behavioral problems in their children and, on top of that, getting a divorce. "The split was not entirely amicable, and there were very hurt and angry feelings all around,” Winston says. “The parents struggled to have a civil conversation and it often escalated into yelling, and then tears, on both sides."

During the sessions, the couple would sit on complete opposite sides of the couch. Sasha would hop in the middle, curl up and fall asleep. Both partners would stroke Sasha at particularly emotional moments, and it helped them calm down. Still, they continued to get agitated, often letting therapy sessions intensify into screaming matches. When that happened, Sasha would quickly get up and walk to the door. Winston used those moments as teaching points.

"We [discussed] that if this is how they interact regularly, their children were likely also picking up on their moods and acting out as a result. This was one of the first times they realized that their children may be impacted by the parents own relationship."

Winston's sessions are one of the ways animal-assisted therapy is changing. Animal-assisted therapy is different from service animals who accompany someone dealing with anxiety or depression. Those are certified as emotional-support animals (ESA), who are daily companions and covered under the Americans With Disabilities Act. Therapy animals, on the other hand, are meant to be used in counseling, whether a professional session or an informal one. Although the American Psychological Association and the American Psychiatric Association have no formal position on animal-assisted therapy, there’s evidence that small practices and individuals are exploring it. Animals are appearing in all sorts of places: in emergency rooms, prisons, juvenile-detention centers, nursing homes and, increasingly, your therapist's office. There are no official numbers yet, but Pet Partners, a nonprofit that registers animals for animal-assisted therapy use (the largest organization to do so in the U.S.), says there were more than 1 million reported interactions between registered animals and patients last year. This number includes everything from nursing-home visits to therapy sessions.

Kathryn Kimbley, director of HumAnima CIC, an animal-assisted therapy service in West Midlands, England, brings her therapy dog Flossie to individual sessions with clients, as well as to larger groups, to comfort patients with depression, behavioral problems or even mental-health issues like PTSD. "Dogs can act very much like a social catalyst. In various settings they will encourage people to interact with one another,” Kimbley says. “It lifts the mood and makes people feel better."

Kimbley has found that her clients feel more at ease talking to her when they're physically distracted. "If someone is talking, they might sort of tap their foot or fidget. They have this energy they want to redirect somewhere, and they have no outlet for it. So if Flossie is in this situation, it is much easier for them."

A therapy pet can also modulate a relationship between a client and his or her counselor. "You are dealing with powerful and overwhelming emotions, but you can't hug a client," says Kimbley. "With a dog present, that need is therefore met."

Emerging research confirms the benefits of pets on people. A 2009 study found that preschool kids with special needs were better able to follow directions during assigned tasks if they were with a trained poodle than when they were alone, with another human or with a stuffed animal dog. Other research has shown that animals are social facilitators: people tend to be viewed as more trustworthy if they have a pet, and pets are known to instigate more conversations among strangers. Animals can also lower a person's anxiety level. "You can see some of the same changes in physiological response from looking at a fish tank as you do with petting a dog, cat or a horse," says Sheryl Pipe, an adjunct professor of anthrozoology (the study of human-animal interaction) at Canisius College in Buffalo, N.Y. "But in terms of social facilitation, that is better suited for mammals."

Of course, there are certain people who don’t respond well to animals in their sessions, and therapists need to distinguish between those who will benefit and those who need pet-free space. And not just any animal will work. Therapy animals are most successful when they’re a bit older and have more experience. There are no set guidelines for training animals used in therapy, and many groups use their own rubrics. Kimbley makes sure her animals are properly socialized and can react normally in a variety of situations.

But, Pipe warns, a therapy animal should be considered a partner rather than a tool. "We tend to have a greater willingness to consider the impact on our partner than our tools. We have to make sure an animal is happy participating and still has adequate time to behave like the animal that they are," says Pipe.

"The field is still relatively in its infancy, but the data that's beginning to come in is really encouraging in terms of how impactful this work can be." Man’s best friend, it seems, can also be man’s best medicine.