The Science Behind Animal-Assisted Therapy


Animal-assisted therapy is a complementary medicine intervention, typically utilizing dogs trained to be obedient, calm, and comforting. Several studies have reported significant pain relief after participating in therapy dog visits. Objective reports of reduced pain and pain-related symptoms are supported by studies measuring decreased catecholamines and increased endorphins in humans receiving friendly dog visits. Mirror neuron activity and disease-perception through olfactory ability in dogs may also play important roles in helping dogs connect with humans during therapeutic encounters. This review will explore a variety of possible theories that may explain the therapeutic benefits that occur during therapy dog visits.

This is a preview of subscription content, access via your institution.

Fig. 1


Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

  1. 1.

    Muñoz Lasa G, Ferriero G, Brigatti E, Valero R, Franchignoni F. Animal-assisted interventions in internal and rehabilitation medicine: a review of the recent literature. Panminerva Med. 2011;53:129–36.

    PubMed  Google Scholar 

  2. 2.

    Kniseley JS, Barker SB, Barker RT. Research on benefits of canine-assisted therapy for adults in nonmilitary settings. US Army Med Dep J. 2012, Apr–Jun:30–37.

  3. 3.

    Lefebvre SL, Golab GC, Christensen E, et al. Guidelines for animal-assisted interventions in health care facilities. Am J Infect Control. 2008;36:78–85.

    PubMed  Article  Google Scholar 

  4. 4.

    • Marcus DA, Bernstein CD, Constantin JM, et al. Animal-assisted therapy at an outpatient pain management clinic. Pain Med. 2012;13:45–57. Prospective, controlled study investigating impact of a therapy dog on patients, visitors, and staff in an outpatient pain clinic.

    PubMed  Article  Google Scholar 

  5. 5.

    Halm MA. The healing power of the human–animal connection. Am J Crit Care. 2008;17:373–6.

    PubMed  Google Scholar 

  6. 6.

    Allen K, Shykoff BE, Izzo JL. Pet ownership, but not ACE inhibitor therapy, blunts home blood pressure responses to mental stress. Hypertension. 2001;38:815–20.

    PubMed  CAS  Google Scholar 

  7. 7.

    Allen K, Blascovich J, Mendes WB. Cardiovascular reactivity and the presence of pets, friends, and spouses: the truth about cats and dogs. Psychosom Med. 2002;64:727–39.

    PubMed  Article  Google Scholar 

  8. 8.

    Charnetski CJ, Riggers S, Brennan FX. Effect of petting a dog on immune system function. Psychol Rep. 2004;95:1087–91.

    PubMed  Google Scholar 

  9. 9.

    Baird AD, Scheffer IE, Wilson SJ. Mirror neuron system involvement in empathy: a critical look at the evidence. Soc Neurosci. 2011;6:327–35.

    PubMed  Article  Google Scholar 

  10. 10.

    Sobo EJ, Eng B, Kassity-Krich N. Canine visitation (pet) therapy: pilot data on decreases in child pain perception. J Holist Nurs. 2006;24:51–7.

    PubMed  Article  Google Scholar 

  11. 11.

    Lust E, Ryan-Haddad A, Coover K, Snell J. Measuring clinical outcomes of animal-assisted therapy: impact on resident medication usage. Consult Pharm. 2007;22:580–5.

    PubMed  Article  Google Scholar 

  12. 12.

    Coakley AB, Mahoney EK. Creating a therapeutic and healing environment with a pet therapy program. Complement Ther Clin Pract. 2009;15:141–6.

    PubMed  Article  Google Scholar 

  13. 13.

    Braun C, Stangler T, Narveson J, Pettingell S. Animal-assisted therapy as a pain relief intervention for children. Complement Ther Clin Pract. 2009;15:105–9.

    PubMed  Article  Google Scholar 

  14. 14.

    Marcus DA, Bernstein CD, Constantin JM, et al. Impact of animal-assisted therapy for outpatients with fibromyalgia. Pain Med. 2013;14:43–51.

    PubMed  Article  Google Scholar 

  15. 15.

    Celiker R, Borman P, Oktem F, Gökçe-Kutsal Y, Başgöze O. Psychological disturbance in fibromyalgia: relation to pain severity. Clin Rheumatol. 1997;16:179–84.

    PubMed  Article  CAS  Google Scholar 

  16. 16.

    Bair MJ, Robinson RL, Katon W, Kroenke K. Depression and pain comorbidity: a literature review. Arch Intern Med. 2003;163:2433–45.

    PubMed  Article  Google Scholar 

  17. 17.

    Kroenke K, Wu J, Bair MJ, et al. Reciprocal relationship between pain and depression: a 12-month longitudinal analysis in primary care. J Pain. 2011;12:964–73.

    PubMed  Article  Google Scholar 

  18. 18.

    Consoli G, Marazziti D, Ciapparelli A, et al. The impact of mood, anxiety, and sleep disorders on fibromyalgia. Compr Psychiatry. 2012;53:962–7.

    PubMed  Article  Google Scholar 

  19. 19.

    Banks MR, Banks WA. The effects of animal-assisted therapy on loneliness in an elderly population in long-term care facilities. J Gerontol A Biol Sci Med Sci. 2002;57:M428–32.

    PubMed  Article  Google Scholar 

  20. 20.

    Kawamura N, Niiyama M, Niiyama H. Long-term evaluation of animal-assisted therapy for institutionalized elderly people: a preliminary result. Psychogeriatrics. 2007;7:8–13.

    Article  Google Scholar 

  21. 21.

    Odendaal JJ, Meintjes RA. Neurophysiological correlates of affiliative behaviour between humans and dogs. Vet J. 2003;165:296–301.

    PubMed  Article  CAS  Google Scholar 

  22. 22.

    Barker SB, Knisely JS, McCain NL, Best AM. Measuring stress and immune response in healthcare professionals following interaction with a therapy dog: a pilot study. Psychol Rep. 2005;96:713–29.

    PubMed  Article  Google Scholar 

  23. 23.

    Beetz A, Uvnäs-Moberg K, Julius H, Kotrschal K. Psychosocial and psychophysiological effects of human-animal interactions: the possible role of oxytocin. Front Psychol. 2012;3:234.

    PubMed  Google Scholar 

  24. 24.

    Miller SC, Kennedy C, Devoe D, et al. An examination of changes in oxytocin levels in men and women before and after interaction with a bonded dog. Anthrozoös. 2009;22:31–42.

    Article  Google Scholar 

  25. 25.

    Handlin L, Hydbring-Sandberg E, Nilsson A, et al. Short-term interaction between dogs and their owners—effects on oxytocin, cortisol, insulin and heart rate—an exploratory study. Anthrozoös. 2011;24:301–16.

    Article  Google Scholar 

  26. 26.

    Kanamori M, Suzuki M, Yamamoto K, Kanda M, et al. A day care program and evaluation of animal-assisted therapy (AAT) for the elderly with senile dementia. Am J Alzheimers Dis Other Dement. 2001;16:234–9.

    Article  CAS  Google Scholar 

  27. 27.

    Haubenhofer DK, Kirchengast S. Physiological arousal for companion dogs working with their owners in animal-assisted activities and animal-assisted therapy. J Appl Anim Welf Sci. 2006;9:165–72.

    PubMed  Article  CAS  Google Scholar 

  28. 28.

    Zamir T. The moral basis of animal-assisted therapy. Soc Anim. 2006;14:179–99.

    PubMed  Article  Google Scholar 

  29. 29.

    Fabbri-Destro M, Rizzolatti G. Mirror neurons and mirror systems in monkeys and human. Physiology. 2008;23:171–9.

    PubMed  Article  Google Scholar 

  30. 30.

    • Oztop E, Kawato M, Arbib MA. Mirror neurons: functions, mechanism and models. Neurosci Lett. In press. Recent review describing mirror neurons and the models that may utilize them.

  31. 31.

    •• Molenberghs P, Cunnington R, Mattingley JB. Brain regions with mirror properties: a meta-analysis of 125 human fMRI studies. Neurosci Biobehav Rev. 2012;36:341–9. Meta-analysis of human fMRI studies investigating mirror neurons for motor and non-motor stimuli.

    PubMed  Article  Google Scholar 

  32. 32.

    Hennenlotter A, Schroeder U, Erhard P, et al. A common neural basis for receptive and expressive communication of pleasant facial affect. NeuroImage. 2005;26:581–91.

    PubMed  Article  Google Scholar 

  33. 33.

    Buccino G, Lui F, Canessa N, et al. Neural circuits involved in the recognition of actions performed by nonconspecifics: an fMRI study. J Cogn Neurosci. 2004;16:114–26.

    PubMed  Article  Google Scholar 

  34. 34.

    Wells DL. Dogs as a diagnostic tool for ill health in humans. Altern Ther Health Med. 2012;18:12–7.

    PubMed  Google Scholar 

  35. 35.

    Wells DL, Lawson SW, Siriwardena AN. Canine responses to hypoglycemia in patients with type 1 diabetes. J Altern Complement Med. 2008;14:1235–41.

    PubMed  Article  Google Scholar 

  36. 36.

    Marcus DA, Bhowmick A. Survey of migraine sufferers with dogs to evaluate for canine migraine-alerting behaviors. J Altern Complement Med. In press.

  37. 37.

    Marcus DA. The power of wagging tails: a doctor’s guide to dog therapy and healing. New York: Demos Health; 2011.

    Google Scholar 

  38. 38.

    Lippi G, Cervellin G. Canine olfactory detection of cancer versus laboratory testing: myth or opportunity? Clin Chem Lab Med. 2012;50:435–9.

    PubMed  CAS  Google Scholar 

  39. 39.

    Alabama A&M and Auburn Universities. The dog’s sense of smell. Available at Accessed January 2013.

  40. 40.

    • Wilson AD, Baietto M. Advances in electronic-nose technologies developed for biomedical applications. Sensors. 2011;11:1105–76. Comprehensive review of the development and application of electronic nose technology toward detecting and analyzing a broad range of medical conditions.

    PubMed  Article  CAS  Google Scholar 

  41. 41.

    Miller DB, O’Callaghan JP. Neuroendocrine aspects of the response to stress. Metabolism. 2002;6 suppl 1:5–10.

    Article  Google Scholar 

  42. 42.

    Anisman H, Hayley S. Inflammatory factors contribute to depression and its comorbid conditions. Sci Signal. 2012;5:pe45.

    PubMed  Article  Google Scholar 

  43. 43.

    Åsberg M, Nugren A, Leopardi R, et al. Novel biomarkers of psychosocial stress in women. PLoS One. 2009;4:e3590.

    PubMed  Article  Google Scholar 

  44. 44.

    Johnson RA, Meadows RL, Haubner JS, Sevedge K. Human-animal interaction: a complementary/alternative medical (CAM) intervention for cancer patients. Am Behav Sci. 2003;47:55–69.

    Article  Google Scholar 

  45. 45.

    Cole KM, Gawlinski A, Steers N, Kotlerman J. Animal-assisted therapy in patients hospitalized with heart failure. Am J Crit Care. 2007;16:575–85.

    PubMed  Google Scholar 

Download references


Dr. Dawn Marcus reported no potential conflicts of interest relevant to this article.

Author information



Corresponding author

Correspondence to Dawn A. Marcus.

Additional information

This article is part of the Topical Collection on Cancer Pain

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Marcus, D.A. The Science Behind Animal-Assisted Therapy. Curr Pain Headache Rep 17, 322 (2013).

Download citation


  • Catecholamines
  • Electronic nose
  • Empathy
  • Endorphin
  • Mirror neurons
  • Therapy dog