New research has extended the growing body of evidence demonstrating the therapeutic value of nature and animals for sick and disabled people. Several studies and editorials, all published in the November 26 BMJ, examined the impacts of nature and animals on physical and mental health. The studies included a randomized controlled trial evaluating the facilitation of dolphins for the treatment of depression and a review of available evidence regarding the impact of pet ownership on health and well-being. The reports seem to support such concepts as "biophilia" and "ecotherapy," two theories that have been gaining more widespread attention in the medical community.

Biophilia was coined in 1984 by Edward O. Wilson, who defined the term as "the connection that human beings subconsciously seek and need with the rest of life." According to the theory of biophilia, human health and well-being are dependent on one’s relationships with the natural environment. The therapeutic implication of such a theory involves ecotherapy. This therapeutic modality is designed to help people find balance, connection, guidance, and healing through deepening their relationship with the natural environment.

DOLPHINS CAN ALLEVIATE DEPRESSION

Christian Antonioli, PhD, and Michael A. Reveley, MD, recruited participants for their dolphin study through announcements on the Internet and radio, as well as those in newspapers and hospitals. Participants were advised that they would be involved in a research study and that they should not expect any improvement in symptoms. Although 105 people responded, only 30 individuals with mild or moderate depressive disorder were ultimately included in the study. Patients were randomized to water therapy either with or without the presence of dolphins. The researchers asked the participants to discontinue antidepressant drugs or psychotherapy at least four weeks prior to enrollment and did not permit the use of antidepressant medication during the study period.

Individuals assigned to animal care therapy received information about dolphin behavior and instruction on water safety. After taking part in a short, structured session to familiarize themselves with the dolphins, the participants were asked to play and swim with and to care for the dolphins.

Participants in the control group were assigned to an outdoor nature program featuring the same water activities as those included in the animal care program but without the presence of dolphins. This was done "to control for the influence of water and other, nonspecific, environmental factors." Participants received information about water safety, the marine ecosystem, and the barrier coral reef. Both the animal care program and the outdoor nature program were run simultaneously for two weeks. To avoid disappointment, patients in the outdoor nature program also received a day session with the dolphins at the end of the study.

Participants in the control group were assigned to an outdoor nature program featuring the same water activities as those included in the animal care program but without the presence of dolphins. This was done "to control for the influence of water and other, nonspecific, environmental factors." Participants received information about water safety, the marine ecosystem, and the barrier coral reef. Both the animal care program and the outdoor nature program were run simultaneously for two weeks. To avoid disappointment, patients in the outdoor nature program also received a day session with the dolphins at the end of the study.

Drs. Antonioli and Reveley found that both water therapy modalities were effective in alleviating symptoms of depression. However, "the animal care program had a significantly higher effect in decreasing the depressive symptoms of the subjects than the outdoor nature program," they said. "The effects exerted by the animals were significantly greater than those of just the natural setting," explained the researchers.

Drs. Antonioli and Reveley found that depressive symptoms improved after only two weeks of treatment, compared with four weeks for conventional therapy (psychotherapy or drug therapy). Three months or longer after participating in the study, 10 patients in the animal care program and three patients in the outdoor nature program who had had a score of 7 or less on the Hamilton Depression Rating Scale at the end of the program provided a self-assessment of their mental health status. Nine of the 10 patients in the animal care program and all three patients in the outdoor nature program reported lasting improvement and did not require treatment during the following three months. The researchers said that "the echolocation system, the aesthetic value, and the emotions raised by the interaction with dolphins may explain the mammals’ healing properties."

They concluded that "the biophilic method of intervention represents a new emphasis in psychiatry and has the potential to bring alternative clinical strategies to the treatment of emotional disorders. Psychiatric rehabilitation occurs operating on the emotional, holistic, and psychophysical aspects of participants through the interaction with animals in nature and the stimulation of the nervous system though the senses."

PET OWNERSHIP FOR BETTER HEALTH?

In another study, June McNicholas and her colleagues found that owning a pet is associated with both positive and negative impacts on health and well-being. Their conclusions are based on a review of existing literature examining the link between pet ownership and health.

According to the researchers, three potential mechanisms have been proposed to explain the association between pet ownership and benefits to human health:

1. There is no real association between pet ownership and health. Cofactors such as personality traits, age, or economic or health status may impact the decision to own a pet, thus producing the appearance of a link between pet ownership and health.

2. Pets may enhance social interactions with other people, thus providing an indirect effect on well-being. Pets can act as social catalysts, leading to greater social contact and therefore to the alleviation of feelings of loneliness and social isolation.

3. The nature of the relationship between pets and humans may have a direct effect on health and well-being. For example, close human relationships have powerful influence on well-being by providing emotional support; they can reduce perceptions of stressful events, protect against anxiety-related illness, and enhance recovery from serious illness.

The researchers suggested that "support from pets may mirror some of the elements of human relationships known to contribute to health." They noted that pet ownership has been found to be of value in the early stages of bereavement and after breast cancer treatment. There is also evidence that pet ownership is associated with a reduced risk of heart disease, lower use of general practitioner services, a reduced risk of asthma and allergies in young children, less sickness-related absenteeism from school, a reduced risk of cardiovascular disease, and higher survival rates from myocardial infarction.

However, despite the purported health benefits of pet ownership, the researchers identified several negative impacts of pet ownership on health and well-being. According to the researchers, conflicts can arise between health interests and pet ownership, causing non-compliance with medical advice. "Up to 70% of pet owners would disregard advice to get rid of a pet owing to allergies, whereas reports abound of older people avoiding medical care through fear of being admitted to hospital or residential care as this often means giving up a pet," they explained.

Richard T. Mayon-White, in an accompanying commentary, noted that zoonoses are another negative health consequence of pet ownership. For example, puppies with diarrhea can be a source of Campylobacter, yet "many people will accept the risks of gastrointestinal infection in exchange for the pleasure of watching a young animal at play, and for the bond between pet and owner that grows with time." He noted that risks could be reduced through better awareness and proper hygiene.

In another editorial, Ambra Burls, RMN, CPN, and Woody Caan, DPhil, suggested that "extra benefits may come from the naturalness factor arising from connection with wildlife," compared with pet ownership. They noted that use of wildlife in some therapies is reported to improve quality of life. Such therapies commonly involve participation in conservation projects and usually address mental health needs. Examples include Ronan Berger’s work with endangered wolves and birds of prey in the Israeli wilderness, as well as Growing Together and Meanwhile Wildlife Garden, two projects in the United Kingdom. "People who take part in conservation projects report subjective health benefits, ascribed to being outdoors and to feeling part of a greater system connecting beyond the individual," they said.

According to Ms. Burls and Dr. Caan, stronger evidence of the association between health and nature are needed, "such as health impact assessments of wildlife projects to determine their objective therapeutic value. Public health, clinical, and educational services need to act to provide this evidence, allowing research and practice to grow together." They added that "partnerships between health care providers and nature organizations to share and exchange expertise could create new policies that recognize the interdependence between healthy people and healthy ecosystems."

—Karen L. Spittler

Suggested Reading
Antonioli C, Reveley MA. Randomised controlled trial of animal facilitated therapy with dolphins in the treatment of depression. BMJ. 2005;331:1231-1234.
Burls A, Caan W. Human health and nature conservation. BMJ. 2005;331:1221-1222.
Mayon-White R. Pets—pleasures and problems. BMJ. 2005;331:1254-1255.
McNicholas J, Gilbey A, Rennie A, et al. Pet ownership and human health: a brief review of evidence and issues. BMJ. 2005;331:1252-1254.

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