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What Do We Really Know about Animal Interventions for Autism?

A photo of a boy on a horse and a boy with a therapy dog

Marina Sarris

Date Revised: January 27, 2023

Adam Lloyd experienced many of the usual autism therapies as a child, but in a most unusual place ─ sitting on a horse.

Adam, who is autistic and deaf, worked with physical, speech, and occupational therapists at The Shea Center for Therapeutic Riding in San Juan Capistrano, California.

During those sessions, and later during adaptive riding lessons, Adam improved his balance, coordination, sign language skills, sensory sensitivity, and self-confidence, says his mother, Kerrie Lloyd. “We used the horse to provide the sensory input so he would pay attention while we were signing to him,” she recalls.

Adam is leaving high school for a community college program this year. “He is a rockstar in his community,” his mother says. “And it began with the therapies he did while riding a horse.”

Lloyd does not need to be convinced that horses can help people with autism develop skills. But others do.

Some experts, including those who believe animal-assisted interventions show promise, acknowledge that research has not made the case for them, at least not yet. Simply put, there are not enough scientifically valid studies to prove that interventions involving animals work for people with autism.1, 2

Some researchers are hoping to change that. Leanne O. Nieforth, Ph.D., is one. She researches human-animal interactions at University of Arizona’s College of Veterinary Medicine. She has heard stories about people who have benefited from animal-assisted interventions, which include:

  • Hippotherapy ─an occupational, physical, or speech therapist uses the movement of a horse to help engage patients’ sensory, neuromuscular, or brain systems to improve their strength, balance, coordination, or language
  • Therapeutic or adaptive horseback riding ─ a riding instructor adapts recreational lessons for people with various conditions
  • Animal-assisted therapy ─ a health care provider uses a dog, horse, or other animal in their practice
  • Service dog ─ a trained dog that performs tasks that are related to a person’s disability.

“We have lots of anecdotal information about how animal-assisted interventions work for people, but a lot of time, people say, ‘It’s magic, it just works!’ Putting the hard data and hard science behind that is my goal as a researcher. I think most researchers would agree with that,” Nieforth says. She discusses her research on animal interventions in this recorded SPARK webinar.

From Anecdotes to Evidence About Animal Interventions for Autism

Some studies have pointed to the potential for animal-assisted interventions to reduce stress or improve social interaction, communication, or motor skills in autistic people.3, 4

Nieforth reviewed 43 published research studies of animal-assisted interventions for autism. Most involved horses or dogs.1 While the number of studies is growing, a positive sign in a small research field, many studies do not meet the requirements of science, she concludes. That means they cannot be used as evidence that the therapy works. “Evidence-based treatments are treatments that have been extensively researched with rigorous research studies,” she explains.

Some studies have too few participants, and others do not have enough information about the animals or therapy procedures that were used, she found. Some do not include a comparison group, which would show whether the animal therapy was better or worse than no therapy or standard therapy. Problems in how a study is designed could make the therapy being tested look more, or even less, effective than it really is.

Studies need to report enough information so that other researchers could repeat them to see if they get similar results, she says.

To complicate matters for researchers and families, animal-assisted interventions and activities may look different from place to place. That is because there is no requirement that providers undergo certain training and follow the same practices and standards, although many do so voluntarily.

Nonetheless, the interventions remain popular, especially within the autism community. That is not surprising given that animals may have a special appeal to many on the spectrum.

The Bond Between People and Animals

People have kept domesticated animals for work or companionship for ages. Today, an estimated 70 percent of U.S. households have a pet. Researchers are studying the “potential physical and mental health benefits” of having dogs, cats, guinea pigs, and more, according to the National Institutes of Health.

Autism advocate Temple Grandin, Ph.D., an animal scientist on the spectrum, has popularized the idea that some autistic people have a natural affinity for animals. She says that she relies heavily on sensory input when thinking, as animals do. “As a person with autism, it is easy for me to understand how animals think because my thinking processes are like an animal’s,” she writes in her essay, “Thinking the Way Animals Do.”5

People with autism often have an intense interest in a topic. Animals were a common interest in a study of almost 2,000 children in the SPARK autism research project.6

Of course, people differ. Some on the spectrum may dislike being around animals, especially if they are sensitive to loud barking or neighing, animal smells, or sudden movements.7

For those who are interested in animals, some researchers ask: could the potential power of the human-animal bond boost the effectiveness of conventional, or evidence-based, therapies?

A Therapy Dog or Therapy with a Dog?

Taylor Chastain Griffin was a dog trainer who brought her own pets to visit people in places such as hospitals. She had registered with the nonprofit Pet Partners, which trains volunteers who bring their pets to assisted living facilities, hospitals, schools, and campuses. Their pets are called therapy animals, although they provide companionship and comfort to people, not therapy.

When Griffin became a mental health counselor, she wanted to incorporate her dog into actual therapy. She realized that many of her fellow counselors had no background in animal training and no place to learn about bringing their animals into their practices. Organizations like Pet Partners provide services to volunteers, not health care providers.

“I witnessed well-intentioned professionals not knowing how to bring their animals into their practice, and I had concerns. I wanted to prevent any animal who doesn’t want to be doing this job from doing it, for the sake of their welfare and for the safety of the patient,” says Griffin, who has a Ph.D. in psychology with a focus on human-animal interaction.

She helped launch the Association of Animal-Assisted Intervention Professionals to educate and certify therapists, doctors, dentists, and others who want to involve animals in their practices. That group is affiliated with Pet Partners, and Griffin works for both.

Some health insurance plans cover therapies by a licensed physical or occupational therapist or psychologist, for example, who incorporates a horse or dog into their sessions, providers and parents say.

As a counselor, Griffin says, she could even use clients’ interest in an animal in therapy without that animal being present. “If I have a client who really loves snakes ─ I don’t have a snake ─ I can incorporate information about snakes in what I do, and I can unlock the power of the human-animal interaction without having to oversee the interaction face to face.”

The Human-Horse Relationship, “as Old as Time”

One of the more popular animal-assisted interventions is therapeutic horseback riding. Despite the name, therapeutic horseback riding is generally considered to be recreation, not therapy. An instructor teaches riding and horsemanship skills to people, with adaptations for their disability or diagnosis. For example, assistants often lead the horse and walk alongside it to keep the rider safe and steady.

One clinical trial of therapeutic riding found that youth with autism who rode horses showed improvements in their speech, social skills, hyperactivity, and irritability, compared with similar youth who did not ride.4

Researchers do not know why that may occur. It may have something to do with the nonverbal communication that occurs when a rider and a horse respond to each other’s movements. Researchers suspect that the riding experience may be calming or may help people to regulate their emotions and sensory systems.

Any barn can offer its version of adaptive riding, but researchers for that study used a riding center affiliated with Professional Association of Therapeutic Horsemanship International, or PATH Intl., a U.S.-based nonprofit that certifies instructors and accredits centers that meet its standards.

People with autism make up the largest portion of therapeutic riders, says PATH Intl. spokesperson Kaye Marks. Therapeutic riding may not be therapy, in the medical sense. Still, “we strongly believe there are therapeutic benefits in horseback riding,” Marks says.

Physical therapist Randi Shannahan agrees that experiencing the movement of a horse, whether in hippotherapy or as a recreational rider, can help people improve motor and other skills. Shannahan is the therapy services manager at The Shea Center for Therapeutic Riding, where Adam Lloyd rode. The Shea Center, a PATH Intl. premier accredited center, has participated in research of physical therapy performed while children are on a horse.

“The human-horse relationship is as old as time, and there’s something there. It’s hard to put scientific, objective measures on it, but all of us can attest to the benefits we have received,” Shannahan says.

Advice for Families Interested in Animal Interventions for Autism

While researchers like Nieforth push for better studies of animal-assisted interventions, many families do not want to wait for the final scientific word.

Researchers and providers alike advise parents who are considering an animal-assisted intervention to ask questions. For example:

“You want to make sure that anyone incorporating a live animal in a session has the competencies to do so,” Griffin says.

Photos provided by Kerrie Lloyd and Melissa Evans.



  1. Nieforth L.O. et al. Rev. J. Autism Dev. Disord. Epub ahead of print (2021) Abstract
  2. National Autism Center. Findings and conclusions: National standards project, phase 2. Randolph, MA (2015) Report
  3. O’Haire M. Appl. Dev. Sci. 21, 200-216 (2017) PubMed
  4. Gabriels R.L. et al. J. Am. Acad. Child Adolesc. Psychiatry 54, 541-549 (2015) PubMed
  5. Grandin T. Accessed Nov. 30, 2022
  6. Nowell K.P. et al. J. Autism Dev. Disord. 51, 2711-2724 (2021) PubMed
  7. Grandin T. et al. Handbook on Animal-Assisted Therapy. chapter 16, 225-236. Academic Press (2015)