DESCRIPTION

• Animal-assisted interventions (AAIs) promote well-being and create a positive healing environment through interaction with an animal, either as an independent activity or integrated into another treatment modality.
• AAIs have been used in mental health care for centuries, with early reports of animal-assisted inpatient models in the 18th century.[1]

MECHANISM

A variety of mechanisms have been proposed:

Biological

• Studies suggest animal interaction can release bonding hormones (dopamine, oxytocin, endorphins), reduce stress hormones (cortisol, epinephrine, norepinephrine), lower heart rate and blood pressure, and modestly affect immune function.[2][3][3][4]
• Evidence is mixed however. The most robust and reliable biological effect is cortisol reduction, especially when stimulus is for a duration greater than 15 minutes.[5]

Psychosocial

• Animals act as catalysts for emotional expression and social engagement, to buffer stress, provide a nonjudgmental presence in the lives of individuals who may feel isolated, misunderstood, or insecure due to their illness.[6][6][7]
• In psychotherapy, animals may act as “social lubricants,” facilitating rapport, or as “mirrors,” providing immediate and unambiguous feedback on behavior.[6][7]

Cognitive

• Animals may promote relaxation by capturing and holding attention, though meta-analyses show no direct effects on cognition itself.[8][9]

Evolutionary

• Canines in particular have evolved to be sensitive to and discriminate among human affective expressions.[10]

INDICATIONS

• AAIs are used across the lifespan in both clinical and healthy populations. They are not first-line treatment but serve best as adjuncts, especially when standard care is poorly tolerated or ineffective.
• AAIs are appropriate for those with difficulty connecting with other people in a therapeutic setting (e.g., autism spectrum disorders, survivors of interpersonal trauma).

CONTRAINDICATIONS

• Contraindications for AAIs are centered around maintaining the safety of both human and animal counterparts during the therapeutic interaction.
• AAIs should not be utilized under the following conditions:
  • Fear, phobia, or traumatic history involving animals, unless exposure therapy is implemented in a controlled manner
  • Allergy to animal fur/dander
  • Individuals whose behavior is highly unpredictable, uninhibited, or agitated
  • Disinterest in animals
  • Immunocompromised patients or those with open wounds, unless proper infection precautions are enacted[11]

TECHNIQUE

• AAIs employ a spectrum of techniques to ameliorate suffering and improve well-being.
• Variability across AAIs includes:
  • Setting
  • Duration
  • Patient population
  • Group versus individual format
  • Content and procedure of the intervention
  • Type of animal
  • Frequency of contact with the animal
  • If the animal has received specialty training, completed a certification program, or was prescribed by a mental health professional
  • Role of human interventionist (e.g., handler, facilitator, therapist)
• Many AAIs are unstandardized, however the field is working toward a more unified framework through national organizations releasing standards of practice guidelines.[12]
• Common standards across the majority of AAIs are:
  • The animal must be under a veterinarian’s care, be compliant in vaccinations, have adequate hygiene, and be free of parasites, active infections, and major health problems.
  • The animal is of appropriate countenance: affectionate toward humans, seeks interaction, obedient, calm.
  • A plethora of animal varieties are acceptable, though mammals, specifically dogs, are the most common.
  • A trained handler is integral for safe and successful implementation of AAIs; handlers must be able to read animal body language, guide the interaction, and set boundaries with patients if necessary.

Several models have emerged as predominant in the field:

• Animal-assisted therapy (AAT)[1]
  • AATs have a formalized protocol with specific and evaluative goal-directed outcomes.
  • Involves credentialed health professionals integrating animals within the scope of their practice (e.g., animal-assisted cognitive-behavioral therapy)
  • Often employs a service model of subsequent sessions that allow for access to the animal
  • Equine-assisted therapy has a similar framework as AAT, though due to the additional skillset involved in handling equines, it is often considered an independent modality.
• Animal-assisted activities (AAAs)[1]
  • AAAs tend to be more spontaneous, less goal-directed in nature, and may not involve patient follow-up.
  • Animal/handler pairs are often required to receive certification.
  • An example is a canine visiting a medical unit to improve inpatients’ psychological status.
  • AAAs can even be as simple as a fish tank placed in a medical office waiting area.
• Emotional support animals
  • These animals are owned by and live with the person they support.
  • An emotional support animal’s close proximity, unconditional positive regard, companionship, and affection may help ameliorate mood symptoms.
  • Bona fide emotional support animals are “prescribed” by mental health professionals, though the animal is not required to receive specialty training or certification.
  • Many professionals consider this modality to be controversial and in a separate category from AAIs.
  • Scientific evidence for the effectiveness of emotional support animals is sparse and mixed, with some indication of iatrogenesis.[13]
• Service animals
  • The U.S. Department of Justice defines service animals as “dogs that are individually trained to do work or perform tasks for people with disabilities.”[14]
  • Certified service animals are covered under the Americans with Disabilities Act, and thus are permitted aboard public transportation, on airlines, and in facilities with otherwise strict policies.

EFFICACY

• The benefits of AAIs have demonstrated proof of concept with moderate effect sizes and show promise in a variety of patient populations.[15]
• Recent systematic reviews show the strongest evidence for reducing acute stress and anxiety, especially in educational and healthcare settings, with weaker evidence for long-term effects.[9]
• Findings are limited by methodological weaknesses including lack of standardized terminology, absence of consensus at a basic definitional level, small sample, limited work on long-term effects, and wide variability in outcome measures and technique.

SPECIAL POPULATIONS

While not a comprehensive list, the following neuropsychiatric populations have the most empirical evidence supporting AAIs:

Mood disorders

• A meta-analysis indicated that AAIs are associated with fewer depressive symptoms.[16]
• A randomized controlled trial of 90 adult psychiatric patients in a 12-week-long farm AAT program found anxiety and depression levels to be significantly lower at follow-up (6 months post-intervention) as compared to baseline.[17]

Dementia

• The majority of studies investigating the impact of AAIs on persons with dementia show a positive effect on social interaction and quality of life as well as lessening agitation and aggression.[18][19][20]
• Recent meta-analysis showed AAIs have notable effects on physical health—supporting greater functional ability and independence in daily self-care tasks—as well as on psychological well-being, including alleviating depressive symptoms and improving cognitive performance on the Mini-Mental State Examination in individuals with Alzheimer’s disease.[21]

Autism

• According to systematic reviews, a considerable number of studies report positive results for the impact of AAIs on autism,[22] though some do have mixed results.[23]
• Most AAIs for autism focus on increased social interaction, improved communication, and decreased problem behaviors (e.g., petting an animal can help teach appropriate social touch through cause and effect of one’s behavior).

ADVERSE REACTIONS

• AAIs can have adverse reactions similar to other psychotherapeutic interventions, such as emotional distress while processing difficult thoughts or memories.
• In a poorly managed program that lacks respect for animal welfare and does not appropriately monitor for warning signs, animals may negatively respond with unwanted behaviors.

References