Although the majority of American households includes a pet, it is only recently that we have begun to explore the relationship between people and their pets and the possible physical and emotional benefits of that relationship.
Although the majority of American households includes a pet, it is only recently that we have begun to explore the relationship between people and their pets and the possible physical and emotional benefits of that relationship. Early surveys reported a strong psychological and emotional attachment between people and their pets, and the term human-animal bond emerged to represent this attachment. Studies revealed that most pet owners view their pets as both enhancing the quality of family life by minimizing tension between family members and enhancing their owner's compassion for living things (Barker, 1993; Pet Theories, 1984; Voith, 1985). Using a projective technique to investigate owners' closeness to their pet dogs, Barker and Barker (1988, 1990) found that dog owners were as emotionally close to their dogs as to their closest family member. They reported that more than one-third of the dog owners in their study were actually closer to their dogs than to any human family member.
With documentation of the strong human-companion animal bond came studies of how pet ownership may affect physical and mental health. Friedmann et al. (1980) conducted one of the first such studies, which compared the survival rates of pet owners and non-pet owners following a myocardial infarction (MI). Controlling for exercise, the investigators found a significantly higher survival rate, one year post-MI, for pet owners. Other studies supporting a cardiovascular benefit associated with pet ownership followed; they are summarized by Patronek and Glickman (1993). Perhaps the largest cardiovascular study of pet owners conducted to date involved over 5,700 participants taking part in a cardiovascular screening program in Australia (Anderson et al., 1992). The results showed that male pet owners had significantly lower systolic blood pressure, and triglyceride and cholesterol levels than males who did not own pets. The study also showed that, of females over the age of 40, those who owned pets had lower systolic blood pressure and triglyceride levels than those who did not.
Other researchers have examined the relationship between pet ownership and more general health factors. Serpell (1991) compared adults before and after they acquired a pet, and found a decrease in minor health problems for pet owners. Examining reported health and morale in older adults living in the community, Lago et al. (1989) found pet ownership and attitudes toward pets to be significant predictors of these variables. Siegel (1990) compared physician utilization of Medicare recipients experiencing stressful life events and found lower utilization among pet owners compared to those who did not own pets. Allen et al. (1991) reported that females had lowered stress levels when their dogs were present compared with the presence of a human best friend or control condition.
Professionals working with children have also written about the benefits of pet ownership. Erikson's (1963) stages of psychosocial development provide a useful framework for considering potential benefits. Pets may contribute to the development of 1) a child's basic sense of trust through the pet's constancy, security, reliability, love and affection, and ability to serve as a transitional object; 2) a sense of autonomy and initiative through the pet's serving as an active playmate and promoting exploration of the environment, and encouraging patience and self-control; 3) a sense of industry through the pet's trainability and response to the child's basic commands; and 4) a sense of identity through the pet's serving as a companion and confidant, and providing social and emotional support (Blue, 1986; Brown et al., 1996; Bryant, 1990; Robin and ten Bensel, 1990). Others have focused on specific qualities that may be enhanced in children growing up in pet-owning households. Some researchers have found that children with pets score higher on measures of empathy, self-esteem and self-concept than those who do not. (Poresky and Hendrix, 1990; Van Houtte and Jarvis, 1995).
Focusing on a clinical population, Barker et al. (1997) showed the strong supportive role of pets in the childhood of sexual abuse survivors. In this retrospective study, they found that, in some cases, the pet was the only reported supportive entity in the survivor's childhood. In sexual abuse survivors, Nebbe (1998) reports that survivors with a strong human-animal bond in childhood report less abusive behavior as adults, and lower anger levels than those lacking a strong bond.
Other researchers have investigated the effects of introducing previously unknown companion animals into health care settings. These activities have ranged from simple visitation by a pet and its owner, to the purposeful inclusion of animals in patient treatment. This animal-assisted therapy has been shown to facilitate the achievement of therapeutic goals.
Studies have found that simply having an animal present or visiting is beneficial to children and adults in some health care situations. Friedmann et al. (1983) observed reductions in children's blood pressure levels when a dog was present during a mildly stressful task. More recently, Wells (1998) found that the presence of a dog during potentially painful medical procedures reduced chronically ill children's physiological and psychological levels of distress. Similarly, Nagengast et al. (1993) found children's levels of distress during physical examinations were lower when a companion animal was present in the room.
Such findings have also been reported for adults. Katcher et al. (1984) reported reduced blood pressure levels for adults watching an aquarium. Others have addressed the positive influence of animals in acute care settings, nursing homes and rehabilitation settings, as well as in psychiatric settings (Barba, 1995; Brickel, 1980; Voelker, 1995). In nursing homes, residents have been found to be less depressed following animal visits (Francis et al., 1985). Patients hospitalized on a psychiatric service have been found to have better group attendance and fewer psychiatric symptoms when caged birds are present (Beck et al., 1986), and increased positive socialization has been found for Alzheimer's patients when a dog was present (Batson et al., 1995).
While receiving heightened media attention in recent years, AAT can be traced back to at least the 18th century when hippotherapy, or therapeutic horseback riding, was used as a medical intervention for improving postural control, joint disturbance, coordination and basic balance (Depauw, 1983). In addition to these physical benefits, hippotherapy has also been noted to improve feelings of self-worth and power as patients are freed from the mechanical supports of wheelchairs and crutches, and are able to move about on a powerful animal (Blue, 1986). Today, horses are also used in psychotherapy to assist patients in improving ego strength, self-confidence and social competence (Schneidhacker, 1994).
An early report of the potential of AAT in mental health care was provided by Boris Levinson, M.D., a Canadian child psychiatrist who included his dog in therapy sessions (1962). Based on his observations of the interaction between his child patients and the dog during therapy sessions, he reported that the dog served as a communication link, provided the child with a sense of security in the therapy setting and quickened the therapy process. Levinson found that AAT worked well with children who were nonverbal, inhibited, autistic, schizophrenic, withdrawn, obsessive-compulsive or culturally disadvantaged. He found the dog particularly beneficial in helping to strengthen autistic children's contact with reality. A more recent and controlled study of autistic children and AAT reported increased social response by children to both animal and therapist (Campbell and Katcher, 1992).
An AAT/nature education program was found to be therapeutic for children in residential treatment for attention-deficit/hyperactive and conduct disorders (Katcher and Wilkins, 1994). The results of this controlled study indicated the AAT program was effective in decreasing agitated and aggressive behavior, improving cooperation with instructors, engaging students in learning, and in improving behavioral control in regular classrooms.
Others have also addressed the potential therapeutic role of companion animals with other psychiatric populations such as those with dissociative disorders, Alzheimer's disease, dementia and other chronic mental illnesses (Arnold, 1995; Corson and Corson, 1978; Fritz et al., 1995; Hundley, 1991). The role of companion animals in psychotherapy, and their ability to serve as a clinical bridge, has also been described by Barker et al. (1997), Draper et al. (1990) and Mallon (1992). Based on clinical observations, such authors assert the ability of companion animals to demonstrate acceptance by allowing themselves to be petted, to reduce the threat of the therapy setting by their presence, and to serve as a distraction while patients discuss painful material.
A recent study documented the anxiolytic effect of animal-assisted therapy with hospitalized psychiatry patients (Barker and Dawson, 1998). Using a controlled, cross-over design, the researchers compared patients' anxiety levels following AAT and following traditional therapeutic recreation (TR) activities. Results revealed significant reductions in anxiety following AAT for patients with mood disorders, psychotic disorders and other disorders. For the comparison group, only patients with mood disorders showed significant reductions in anxiety. Interestingly, the reduction in anxiety levels for the psychotic patients following AAT was twice as great as that found following TR. The researchers speculate that AAT may be less threatening than traditional group activities, that the physical contact such as hugging and petting the dog may result in the same physiological and psychological reductions in stress that have been reported for nonclinical populations, and that the dog may serve as an entertaining distraction.
Although the majority of published studies of AAT involve dogs, other species have been noted to have beneficial effects as well. Several studies have noted the positive effect for mentally challenged children interacting with marine animals. Benefits of interacting with rehabilitated dolphins, sea turtles and fish were reported by Klingel (1993) to include progress toward, and attainment of, treatment goals and improved self-concept, as well as enjoyable recreational experiences. Nathanson and de Faria (1991) studied the orienting nonverbal and verbal responses of children with mental disabilities interacting in water with dolphins or in water with favorite toys away from dolphins. They report more significant improvements in hierarchical cognitive responses when children interacted with the dolphin. They also note the dolphin interaction produced both a greater number and higher level of responses than the interactions without the dolphins.
As with any new field of inquiry, initial reports of the benefits of interacting with companion animals were primarily anecdotal or case reports. Based on such reports, studies of efficacy that often involved small sample sizes and a lack of controls were undertaken. As evidence has continued to accumulate, more rigorous controlled studies are being conducted, resulting in the emergence of a significant body of literature supporting the therapeutic value of the human-companion animal interaction in specific circumstances. However, more research is needed-particularly well-designed outcome studies of AAT programs and longitudinal studies of pet ownership-in order to increase our understanding of the human-companion animal interaction and the potential benefits to quality of life.
Dr. Barker is an associate professor of psychiatry, internal medicine, and anesthesiology at the Medical College of Virginia at Virginia Commonwealth University and an adjunct professor of small animal clinical sciences at Virginia-Maryland Regional College of Veterinary Medicine. She has published numerous papers on the human-companion animal interaction.
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