by Michael D. Anestis, M.S.
I've had an interesting back-and-forth discussion recently regarding the empirical evidence for equine-assisted psychotherapy. As PBB readers no doubt know, I'm not particularly impressed by the evidence-base for this approach and have been openly critical about its frequent use by clinicians in the treatment of mental illnesses. Today, I came across a blog post on PsychCentral made by the individual with whom I have been having this back-and-forth in which a number of citations were listed as evidence of empirical research on the utility of EAP in the treatment of mental illness. My goal here in this post is not to incite a confrontation, but to instead critically review those citations. I will not be linking to the post because I feel as though it will be hard to do this without this article coming across as an attempt to attack the author of the blog, which truly is not my intention. The point in doing this is to demonstrate that simply because something gets published does not mean that it is scientifically rigorous and, even if the scientific rigor is strong, it does not mean that the results support the claims of the authors themselves or those citing the article. We have a way of (often unintentionally) discussing results in a manner that far exceeds what the data actually tell us and, unfortunately, I believe this is demonstrated quite well here. What follows is a list of citations with a description of each and a critique of the evidence they provide for EAP as an efficacious and/or effective treatment for any mental illnesses.
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Schultz, P., Remick-Barlow, G., & Robbins, L. (2007). Equine-assisted psychotherapy: A mental health promotion/intervention modality for children who have experience intra-family violence. Health & Social Care in the Community, 15, 265-271.
In this article, 63 children who had been subjected to intra-family violence received anywhere from 1 to 116 sessions of EAP. The authors found that global assessment of functioning (GAF) scores improved significantly over the course of treatment. On the whole, that is a positive result; however, there are a few significant issues with this study. First, there was no comparison group. In other words, to what degree did common factors account for any improvement. This is particularly notable because the authors found a significant association between number of sessions and level of improvement, a red flag that, without a comparison group, points towards the simple passage of time as a major contributor to improvements. In other words, without a comparison group, it's unclear that people who received EAP improved to any greater degree or at a quicker rate than would people who received no treatment at all. After all, in general, regression to the mean indicates that extreme scores eventually become less extreme - people improve from severe states over time. Evidence of improvement in the abesence of a comparison group confirms that a treatment is not iatrogenic, but it does nothing to support the notion that it is a useful form of treatment.
Also, no psychometrically tested measures of psychopathology were utilized, precluding any analysis of the degree to which individuals saw improvement in their specific diagnoses.
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Trotter, K., Chandler, C., Goodwin-Bond, D., & Casey, J. (2008). A comparative study of the efficacy of group equine assisted counseling with at-risk children and adolescents. Journal of Creativity in Mental Health, 3, 254-284.
In this study, the authors compared EAP and classroom counseling in the treatment of problematic behaviors amongst children perceived as being at risk for poor academic outcomes. Unfortunately, there was no random assignment. Instead, participants chose which treatment they wanted, resulting in 126 participants in the EAP group and 38 in the classroom group. The importance of random assignment in treatment research is paramount. Given that the authors did not report on any between groups differences, this is a serious issue. That being said, even if we decide to overlook that, the important point to consider here is that no participants in this study were diagnosed with a mental illness and no components of the analyses in this paper demonstrated that EAP was useful in the treatment of mental illness.
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Frewin, K. & Gardiner, B. (2005). New age or old sage? A review of equine assisted psychotherapy. The Australian Journal of Counselling Psychology, 6, 13-17.
I have reviewed this paper at length in an earlier PBB article, so I will merely point out that the only empirical data cited in this paper come from a website that gives no information about the study itself and from an unpublished manuscript from a different study conducted more than a decade ago that nonetheless has yet to be published.
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Kaiser, L., Spence, L.J., Lavergne, A.G., & Bosch, K.L. (2004). Can a week of therapeutic riding make a difference? A pilot study. Anthrozoos, 17, 63-72.
This study examined 16 children, all of whom were judged to be physically healthy and without any mental illness and found that, after 5 days of therapeutic riding, self-reported levels of anger and frustration were decreased. Here again, there were no comparison groups and no evidence was provided that EAP is useful in the treatment of mental illness.
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Klontz, B.T., Bivens, A., Leinart, D. & Klontz, T. (2007). The effectiveness of equine-assisted experiential therapy: Results of an open clinical trial. Society and Animals, 15, 257-267.
In this study, 49 individuals at an EAP treatment facility agreed to take part. Only 31 completed the 6-month follow-up portion and the authors failed to report on any results for individuals who did not respond to that final component. This is an issue as individuals who are lost to attrition are often the ones who fail to respond to treatment and, in this case, nearly 40% of the sample fit into that group. Taking this a step further, again there was no comparison group, meaning we're looking at the 60% of the sample that decided to continue participating and examining whether their symptoms improved without any consideration of the internal validity (e.g., did the treatment have any impact or did the passage of time or other common factors drive any significant effects?). On the one hand, there is some preliminary evidence for symptom improvement, but on the other hand, it would be a significant stretch to view this as support for the efficacy of EAP in the treatment of mental illness (again, no documentation of diagnoses, remission rates, etc...).
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Scheidhacker, M., Friedrich, D., & Bender, W. (2002). About the treatment of anxiety disorders by psychotherapeutic riding: Long term observations and results of an experimental clinical study. Krankenhauspsychiatrie, 13, 145-152.
I was unable to find this citation. If anyone has information on this study, I would love to hear about it.
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Zugich, M., Klontz, T., & Leinart, D. (2002). The miracle of equine therapy. Counselor Magazine, 3, 22-27.
This is not an empirical study. It is an opinion piece published in a magazine. Click here to read the article itself, which is available for free.
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So...what is my point here? I am not saying EAP does not work, although I am not a believer in this particular treatment approach. I am saying that there is no evidence that EAP is efficacious and/or effective in the treatment of mental illnesses. This is not an opinion of mine, but rather a statement of fact. Perhaps evidence will emerge indicating that EAP has empirical support for a particular set of mental illnesses, but as of yet this has not happened.
Unfortunately, most individuals do not have training in empirical research and statistical analyses, which makes interpreting published journal articles difficult. On top of this, few people have access to these articles, so even if they wanted to read the source material themselves, they would be unable to do so. Because of this, when we cite articles online and write about them, it is important to make sure that we are accurately representing the nature of the results, otherwise the potential for misinformation to become widespread is problematically high.
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Mike Anestis is a psychology resident at the University of Mississippi Medical Center and a doctoral candidate in the clinical psychology department at Florida State University.
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