Animal Assisted Therapy Research Papers

Animal-Assisted Therapy Research Findings

Animal Assisted Therapy & What Science Says

For Mental Health:

  • The simple act of petting animals releases an automatic relaxation response.
    • Humans interacting with animals have found that petting the animal promoted the release of serotonin, prolactin and oxytocin- all hormones that can play a part in elevating moods.
  • Lowers anxiety and helps people relax.
  • Provides comfort.
  • Reduces loneliness.
  • Increases mental stimulation.
    • Assist in recall of memories and help sequence temporal events in patients with head injuries or chronic diseases such as Alzheimer’s disease.
  • Can provide an escape or happy distraction.
  • Can act as catalysts in the therapy process.
    • May help break the ice.
    • May reduce the initial resistance that might accompany therapy.

For Physical Health:

  • Lowers blood pressure and improves cardiovascular health.
  • Reduces the amount of medications some people need.
  • Breathing slows in those who are anxious.
  • Releases many hormones such as Phenylethylamine which has the same effect as chocolate.
  • Diminishes overall physical pain.
  • Relax more during exercise.
    • Participants were motivated, enjoyed the therapy sessions more, and felt the atmosphere of the session was less stressful during Animal-Assisted therapy.
  • For Children with Autism
    • Many children with autism feel a deep bond with animals and feel that they are able to relate better than humans.
    • Children with autism were engaged in significantly greater use of language as well as social interaction win their therapy sessions that incorporated animals compared to standard therapy sessions without them.

Animal-Assisted Therapy Research Findings

Animal-assisted therapy in patients hospitalized with heart failure

American Journal of Critical Care, 2007 (

Health benefits of animal-assisted interventions

Complementary Health Practice Review, 2007 (Download PDF)

Children with autism and therapy dogs in social interaction

Journal of the Society for Psychological Anthropology, 2010 (Download PDF)

Dementia and animal-assisted therapy

American Journal of Alzheimer's Disease and Other Dementias, 2003 (Download PDF)

Dogs ease anxiety, improve health status of hospitalized heart failure patients

American Heart Association Abstract 2513 (Download PDF)

Benefits of animal-assisted therapy in hosptial ICUs

John Hopkins University, 2018 (Download PDF)

DALLAS, Nov. 15 - When it comes to health care, "going to the dogs" is a good thing, according to new research reported at the American Heart Association's Scientific Sessions 2005.

Researchers discovered that a 12-minute visit with man's best friend helped heart and lung function by lowering pressures, diminishing release of harmful hormones and decreasing anxiety among hospitalized heart failure patients. Benefits exceeded those that resulted from a visit with a human volunteer or from being left alone.

Animal-assisted therapy (AAT) has been shown to reduce blood pressure in healthy and hypertensive patients. It reduces anxiety in hospitalized patients, too.

Still, the therapeutic approach of using dogs to soothe people's minds and improve health has been considered more a "nicety" than credible science, said Kathie M. Cole, R.N., M.N., C.C.R.N., lead author of the study and a clinical nurse III at the UCLA Medical Center in Los Angeles.

To determine the potential benefits of animal-assisted therapy on health, the researchers studied 76 hospitalized heart failure patients and their reactions to a visit from either a human volunteer and dog team, a human volunteer only or no visit (the at-rest group). Patients were randomly assigned to one of these three approaches.

"We looked at the dogs' effects on variables that characterize heart failure, including changes in cardiac function, neuroendocrine (stress hormone) activation and psychological changes in mood," Cole said.

The intervention lasted 12 minutes. In the volunteer-dog team group, specially trained dogs (of 12 different breeds) would lie on patients' beds, so patients could touch them while interacting with the volunteer-dog team.

Researchers monitored patients' hemodynamics - the collective system of measurement for blood volume, heart function and resistance of the blood vessels. They measured hemodynamic pressures just before the 12-minute intervention, eight minutes into the intervention and four minutes after the intervention. Investigators also measured epinephrine and norepinephrine levels at these three time points, and administered an anxiety test before and after the intervention.

Researchers found that anxiety scores dropped 24 percent for participants who received a visit from the volunteer-dog team. Scores for the volunteer-only group dropped 10 percent and the at-rest group's score did not change. Researchers measured anxiety with the Spielberger's self report state anxiety inventory.

Levels of the stress hormone epinephrine dropped an average 14.1 picograms/mL or 17 percent in the volunteer-dog team group; 2 percent in the volunteer-only group; and rose an average of 7 percent in the at-rest group.

Pulmonary capillary wedge, the measurement of left atrial pressure, dropped an average 2.1 mmHg, or 10 percent, at the end of the intervention for those receiving volunteer-dog team therapy. However, it increased 3 percent for the volunteer-only group and increased 5 percent for the at-rest group.

Systolic pulmonary artery pressure, a measure of pressure in the lungs, dropped in the volunteer-dog team group 5 percent during and 5 percent after therapy. It rose during and after therapy in the other two groups.

The volunteer-dog team group showed more improvement than the volunteer-only group in right atrial pressure, norepinephrine level and heart rate.

"This study demonstrates that even a short-term exposure to dogs has beneficial physiological and psychosocial effects on patients who want it," Cole said. "This therapy warrants serious consideration as an adjunct to medical therapy in hospitalized heart failure patients. Dogs are a great comfort. They make people happier, calmer and feel more loved. That is huge when you are scared and not feeling well."

Co-authors are Anna Gawlinski, R.N., D.N.Sc., and Neil Steers, Ph.D.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.

Notes: This study is the first randomized Animal-assisted therapy trial to look at subjects with severe heart failure in the critical care setting. Norepinephrine and epinephrine catecholamines have not been looked at before in addition to the cardiopulmonary measurements utilzing a pulmonary artery catheter.

Twelve different breeds participated which helps to add external validity to that portion of the study. The breeds happened to include two golden retrievers, 1 Great Pyrenese, 1 Std poodle, 1 German shephard, 1 dachshund, 2 labrador retrievers, 1 irish setter, 1 Bernese Mountain dog, 1 border collie, 1 miniature schnauzer.

No incidents or negative encounters have occurred with the dogs certified in the People Aninmal Connection Program at UCLA Medical Center.



Animal-assisted therapy is defined as the positive interaction between an animal and a patient within a therapeutic framework. Previous studies have reported on the beneficial effects of animal-assisted therapy with patients suffering from anxiety, a major challenge for professionals caring for patients with intellectual disability. The presence of psychiatric comorbidities such as depression or anxiety within this population is two to four times higher than in the general population. Finding new treatment options for such anxiety disorders is important. The aim of this observational study was to explore whether the level of anxiety decreased when a dog was present during therapy for people with learning disability.


This was an observational study which involved 53 adult patients with mild learning disabilities (26 men) average age, 36.5 ± 11.2 years.

The State-Trait Anxiety Inventory (STAI) was completed by participants with the therapist, before and after two 30-min therapeutic sessions, one in the presence of a dog and the other with only the therapist.


The STAI score significantly decreased after the session with the dog, which was not the case after the session without the dog). After the animal-assisted session, the STAI score was significantly lower (Z = −4.654; p < 0.0001), which was not the case for the session without the dog (Z = −1.054; p = 0.295). There was a significant difference in anxiety between men and women.


Results suggest that there are positive benefits of animal-assisted therapy for individuals with learning disabilities which require confirmation in a randomized controlled trial.

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