CAT, Dogs, and Science

photos of dogs
A selection of PHCoE’s furry friends
By Chris Crowe, Ph.D., and Brad Belsher, Ph.D.
November 6, 2017

CAT, or canine assisted therapy, is an intuitive treatment for potentially many mental health disorders. And, most of us love dogs. Folklore has even designated these canine companions mankind’s best friend. Their appeal is strong and clear, yet their connection to mental health treatment is a bit less evolved.

Unlike many other areas of scientific inquiry, it is difficult to approach questions related to canine involvement in therapeutic activities in a dispassionate way. With our strong attachments to dogs, we may be prone to see the therapeutic benefits of these creatures based on our gut feelings, testimonials, and personal beliefs. After all, before we had science, we relied on these personal forms of information to identify potential treatments. Unfortunately, these sources of subjective information can potentially mislead us to draw premature conclusions about what actually works. For this very reason, we need to keep an open mind and maintain focus on how science works and trust the process.

The scientific method provides a more objective process to build a testable body of knowledge that is equally open to rejection or confirmation. Although sometimes imperfect, the scientific method is our best way of determining whether there is a signal among all the noise (i.e., the hype and the data). Not relying on the scientific framework risks sending us down the slippery slope back to a time when we used ineffective and often harmful treatments, in our distant (e.g., bloodletting, animal magnetism) and not so distant (e.g., eugenics, lobotomy, rebirthing therapy) past.

Recently, there has been increasing interest in using dogs to treat posttraumatic stress disorder (PTSD). Anecdotal reports abound on the therapeutic benefits of dogs to treat PTSD and other mental health conditions. As providers and patients consider the potential benefits and possible harms of canines in treating PTSD, it’s important to return to this scientific framework that has advanced health care in incredible ways and helped us separate the wheat from the chafe. Regardless of the gut feeling we have for any particular treatment, the systematic process for understanding the benefits and harms of a treatment are the same.   

Despite the growing number of advocates for canine assisted therapy (just google “dogs and PTSD”), the evidence base is very limited. Clearly, the scientific findings are not the driver of this enthusiasm. As of this writing, there is no randomized controlled research evaluating the therapeutic effect of canines on reducing PTSD symptoms among symptomatic patients. Although multiple reviews have been published summarizing the research regarding the mental health benefits derived from multiple forms of contact with animals, findings repeatedly indicate that the research in this area is characterized by pervasive methodological limitations that make it impossible to conclude that there are either clearly positive or negative effects (e.g., Herzog, 2011; Marino, 2012; Palley, O’Rourke, & Niemi, 2010). Thus, as stated in our recently published Psych Health Evidence Brief, CAT for PTSD is not considered an evidence-based treatment.  

Some may argue that veterans and service members love their dogs so why not allow them to use CAT for treatment. In fact, some veterans may rightly claim that they’re able to go more places and feel calmer in the presence of their dog. But there are several important counter-arguments to these positions. First, we have greater confidence in front-line treatments that have demonstrated effectiveness in treating PTSD. Offering canine therapy in replacement of effective treatments does a disservice to our service members and is ethically inconsistent with our duties as providers. Second, our current models of effective treatment for PTSD focus on overcoming avoidance associated with the trauma. Thus, while at the beginning of treatment a dog could hypothetically be used as a “prop” to help patients encounter avoided thoughts/feelings/behaviors, the ultimate goal is for the patient to develop greater functioning independently and without the need of relying on anything or anybody – research repeatedly demonstrates this. Third, there are considerable differences in the training backgrounds and professional vocabulary of advocates for CAT. CAT has not been defined as one specific treatment, but is rather a general movement that has not been standardized or manualized. Finally, the significant resources that would need to be invested in approving and providing canine therapy across the Department of Defense and Department of Veterans Affairs health systems, despite the lack of evidence, would take away resources aimed at providing and improving upon validated services and treatments for service members and veterans.

There are important considerations to keep in mind when thinking about emerging therapies, especially those characterized by enthusiasm and limited evidence.

  • Be wary of touted breakthroughs that are based on an oversimplification of the problem and the solution. Advocates often push information out through the media and public interest stories while the more objective, empirical literature is less accessible.
  • Basic and preliminary research is an important step in identifying effective treatments. However, anecdotes, psychophysiological data, and uncontrolled empirical findings alone do not meet the scientific burden required to demonstrate an evidence-based treatment.
  • The scientific method is an open system. This means that as new research emerges, it becomes incorporated into our understanding of what is and is not effective. Specifically, if a high quality randomized controlled trial on CAT for PTSD does emerge, it will undoubtedly become incorporated into our broader understanding of the evidence and become reflected in practice guidelines.

Visit the Evidence Synthesis and Dissemination section to read or download our full set of Psych Health Evidence Briefs.

Dr. Chris Crowe works for the Veterans Health Administration Office of Mental Health and Suicide Prevention and also serves as a senior mental health consultant/liaison to the Psychological Health Center of Excellence. His primary areas of focus include DoD/VA mental health collaborations, VA mental health policy initiatives, advancing evidence-based mental health practice in VA, and VA clinician training programs in evidence-based psychotherapies and psychosocial interventions.

Dr. Brad Belsher is the chief of research translation and integration at the Psychological Health Center of Excellence and directs the Evidence Synthesis and Dissemination (ES&D) effort. He has been actively involved in clinical practice, program development, and psychological health research in the VA and DoD over the past decade. His primary areas of focus include deployment-related mental health, systematic review methodologies, health services research, dissemination of evidence-based mental health practice, and collaborative care.

The views expressed in Clinician's Corner blogs are solely those of the author and do not necessarily reflect the opinion of the Psychological Health Center of Excellence or Department of Defense.


  • Strong work!

  • Dogs are family members, and like human family, can be either helpful or harmful, depending on a variety of factors which are probably beyond the scope of research. I am happy to see leadership stepping back and asking good questions, especially since my VA is currently struggling with untrained "service dogs" whose bad behavior is becoming more problematic for everyone. A potentially disastrous mix involved a "service chicken" in the room with untrained "service dogs." Additionally, one of the problems we have in mental health is the idea that our goal is to make people feel better. I would argue that having better function is actually a better goal, and does not necessarily mean feeling less distress. Additionally, if an untrained "emotional support animal" helps the designated patient but negatively affects other people, how do we account for that in our research? (By the way, I am an animal lover.)

    Thanks for asking some very good questions.

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