Interestingly, not all therapeutic animal research is focused on humans. Studies have found that animals may also benefit from the exchange. Researchers reported that shelter dogs involved in therapeutic programs, like those helping veterans readjust to being at home, are significantly more likely to be adopted, likely due to the additional exercise and socialization.

As the scientific foundation supporting the benefits of animal-human interactions grows, there are four ways that animals are increasingly involved in psychiatric support:

1. Service Animals

Service animals, also referred to as assistance animals, are specially trained to work with or perform tasks for people with disabilities. A psychiatric service dog, for example, might be responsible for stopping someone from engaging in self-mutilating behavior, reminding someone to take his or her medication, or turning the lights on in an empty room for someone with anxiety. Service animals are protected under the Americans with Disabilities Act (ADA), and have the right to accompany their owners in any public space.

2. Emotional Support Animals

Although many use the terms “service animal” and “emotional support animal” interchangeably, there are important legal differences. Emotional support animals (ESAs) provide therapeutic support to people with mental illness; however, they are not specially trained and thus, are not covered under the ADA. Instead, ESAs have fewer legal protections. Under the Air Carrier Access Act, they are required to fly in airplanes for free and under the Fair Housing Act, they are allowed in otherwise pet-free housing, including dorms.

Although the U.S. lacks a centralized registry of emotional support dogs, a study from the University of California at Davis reported the number of ESAs registered by animal control facilities in California increased 1,000% between 2002 and 2012. This recent, dramatic rise of emotional support animals and the accompanying surge of certifying letter requests, has led some therapists to call for a strict, standardized evaluation model.

3. Animal Assisted Activities

Animal assisted activities (AAAs) provide motivational, educational or recreational opportunities to enhance quality of life. AAAs are delivered in a variety of environments, often by paraprofessionals or volunteers. Visits can be brief and spontaneous; often animal assisted activities involve meet-and-greet sessions of pets in hospitals or long-term care centers.

4. Animal Assisted Therapy

Animal assisted therapy (AAT) in counseling involves an intentional intervention, implemented by a licensed mental health professional, that is part of the client’s treatment process. Generally, AAT is a structured and goal-directed process led by a health provider with expertise about the clinical applications of human-animal interactions. Animal-assisted therapy is designed to promote improvement in human physical, social, emotional or cognitive function. AAT may be group or individual in nature and may be provided in a variety of settings.