Effectiveness of animal-assisted therapy: A systematic review of randomized controlled trials

doi:10.1016/j.ctim.2013.12.016

Complementary Therapies in Medicine

Volume 22, Issue 2, April 2014, Pages 371-390

https://doi.org/10.1016/j.ctim.2013.12.016 Get rights and content

Summary

The objectives of this review were to summarize the evidence from randomized controlled trials (RCTs) on the effects of animal-assisted therapy (AAT). Studies were eligible if they were RCTs. Studies included one treatment group in which AAT was applied. We searched the following databases from 1990 up to October 31, 2012: MEDLINE via PubMed, CINAHL, Web of Science, Ichushi Web, GHL, WPRIM, and PsycINFO. We also searched all Cochrane Database up to October 31, 2012. Eleven RCTs were identified, and seven studies were about “Mental and behavioral disorders”. Types of animal intervention were dog, cat, dolphin, bird, cow, rabbit, ferret, and guinea pig. The RCTs conducted have been of relatively low quality. We could not perform meta-analysis because of heterogeneity.

In a study environment limited to the people who like animals, AAT may be an effective treatment for mental and behavioral disorders such as depression, schizophrenia, and alcohol/drug addictions, and is based on a holistic approach through interaction with animals in nature.

To most effectively assess the potential benefits for AAT, it will be important for further research to utilize and describe (1) RCT methodology when appropriate, (2) reasons for non-participation, (3) intervention dose, (4) adverse effects and withdrawals, and (5) cost.

Introduction

Animals have been our companions since ancient times, and we are well aware of the many ways that some of them have aided us throughout history.¹ Animals are used to help humans in ways; for example, serving as working shire horses and guide dogs for the blind.² The modalities that use animals as tools for improving physical, mental and social functions, and educational and welfare aspects of humans are called animal-assisted interventions (AAI).

To understand the different types of AAI and integrate some useful definitions, we accepted the classification of the American Veterinary Medical Association (AVMA).³ The AVMA classifies AAI into three category: (i) animal-assisted activities (AAA) that utilize companion animals, (ii) animal assisted-therapy (AAT) that utilizes therapy animals, and (iii) service animal programs (SAP) that utilize service animal. Especially, AAT is a goal-directed intervention in which an animal that meets specific criteria is an integral part of the treatment process. These programs are usually directed and delivered by human health or human services professionals with specialized expertise and within the scope of practice of their profession.

A pioneer systematic review (SR) of AAT showed that overall it was associated with moderate effects in improving outcomes in four areas: autism-spectrum symptoms, medical difficulties, behavioral problems, and emotional well-being.⁴ However, contrary to expectations, characteristics of the SR participants and studies did not produce differential outcomes. Some limitations of the SR were that it only included articles published prior to 2004, and it did not include randomized controlled trials (RCTs).

It is well known in research design that evidence grading is highest for a SR with meta-analysis of RCTs. Although many studies have reported the effects of AAT,1, 4, 5 there is no SR of the evidence based on RCTs. Therefore, the objective of this review was to summarize the evidence from RCTs on the effects of AAT.

Section snippets

Types of studies

Studies were eligible if they were RCTs.

Types of participants

There was no restriction on participants.

Types of intervention and language

Studies included at least one treatment group in which AAT was applied. The definition of AAT in this study was based on the classification of the AVMA.³ Type of animal was not a restriction but we excluded robotic animals (e.g., robotic dog). There was no restriction on the basis of language.

Types of outcome measures

We focused on all cure and rehabilitation effects using the International Classification of Diseases-10 (ICD-10).

Bibliographic database

We searched

Study selection

The literature searches based on databases included potentially relevant articles (Fig. 1). Abstracts from those articles were assessed, and 57 papers were retrieved for further evaluation (checks for relevant literature). Forty-six publications were excluded because they did not meet the eligibility criteria (see Appendix). Eleven studies12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 met all inclusion criteria (Table 1).

Study characteristics

The language of all eligible publications was English. Target diseases and/or

Discussion

This is the first SR of the cure effectiveness of ATT based on RCTs. Our study is unique because it summarized the evidence for each target disease according to ICD-10 classification. We assume that this study will be helpful to researchers who want to understand the effect of ATT comprehensively, and it could provide indispensable information for the organization that is going to make the guidelines according to each disease.

Among the 11 RCTs that were identified, target diseases and/or

Conclusion

To most effectively assess the potential benefits of AAT, it will be important for further research to utilize and describe (1) RCT methodology when appropriate, (2) the reasons for non-participation, (3) intervention dose,

Contributors

TH, JK, SP, SO, HO, SH, HP, TO, and TA conceived the study and take responsibility for the summary of included studies and data extraction. KT and YM are the guarantors. HK and SO designed the study. HO, SP, TH and HK assessed the quality of articles. All authors critically described the manuscript for important intellectual content.

Funding

This study was supported by the Health and Labour Sciences Research Grants (Research on Health Security Control: ID No. H24-021; representative; Dr. Tsutani K) from the Japanese Ministry of Health, Labour and Welfare of Japan in 2012.

Conflict of interest statement

None declared.

Ethical approval

Not required.

Data sharing

No additional data available.

Acknowledgements

We would like to express our appreciation to Ms. Rie Higashino and Ms. Rinako Kai (paperwork), and Ms. Satoko Sayama (all searches of studies) for their assistance in this study.

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