What is PTSD/TBI?

Research by Gillett & Weldrick

Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder


Research on the use of service animals, and service dogs more specifically, is a quickly expanding field of inquiry. Interest at the intersection between human health care and animals is growing among policy makers, health care providers and various individuals with health problems. In a recent study of media coverage of service dog use among veterans, Taylor et al. (2013) found that this interest is translating into growing public acceptance of the contribution of animals, not only as a form of assistance for those with physical disabilities, but as a mental health treatment or intervention. A body of conceptual and empirical knowledge is emerging on the effectiveness of service dogs in a therapeutic context. This research provides the basis for future direction in research and policy development. This analytical review is organized around emergent and salient themes in research on PSD and PTSD among veterans. The themes are: Benefits (biomedical; psychological; emotional/mental; social); Safety Concerns; Cost Effectiveness; (Psychiatric Service Dogs PDS) PSD as a Treatment; Training, Placement and Regulation; and Challenges. With the limited research on this specific topic, each theme there is reference to broader literature on AAT and mental health that attends to effectiveness, broadly defined. The conclusion will address the most prevalent theme found in the literature – that there is a great need for more empirical evidence. This theme is discussed in the relation to potential studies that could be conducted in Canada, as well as how these potential studies may fit with current and future studies on the international stage.

Understanding the Complexity of Using PSD for Veterans with PTSD

The most appropriate means by which to understand and evaluate the effectiveness of animals as treatments in the area of health and mental health is a subject of debate. A trend toward evidenced-based medicine in health care has drawn attention to the need for rigorous, scientific studies that can be used to inform best practice guidelines. This approach uses randomized clinical control trials as a ‘gold standard’ for evidence of effective treatment (Guyatt et al., 1992). At the same time, there is also a growing recognition for the need to take into consideration interpretative research that, while still following a rigorous research design, explores the social, political, historical and cultural components of treatment effectiveness (Mykhalovskiy & Weir, 2004). Understanding the complexity of treatment effectiveness means, if possible, relying on both approaches to research.

The use of PSD in the treatment for post-traumatic stress disorder among veterans is a particular complex topic of research. As a mental health problem, post-traumatic stress disorder is itself multidimensional. PTSD is often difficult to diagnose, and is experienced with different severities and in different forms. The response to available treatments is difficult to predict with Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder certainty (Green et al., 1989). And, there are a range of psychological, personal, cultural and social factors that influence how it is both experienced and managed (Yehuda & McFarlane, 1995). Further to this, as Marmar (2009) notes, the mental health care needs of veterans involved in recent military action (specifically, Iraq and Afghanistan) are distinct from those experienced by veterans, for example, who participated in the Second World War. Yet, our understanding of how to respond to their needs is still routed through structures introduced 50 years ago. Meeting the treatment needs of veterans who serviced in Iraq and Afghanistan requires responding to their specific and distinct perspectives on trauma and mental health problems. Added to this issue is that the use of psychiatric service dogs is a relatively new treatment for trauma and mental health problems and is debated within the literature on animals-assisted interventions. In fact, many researchers disagree about whether to consider and define psychiatric service dogs as tools, devices, treatments or companions (Tedeschi et al., 2010; Fine, 2010)

The stance taken in this review is that, when available, it is valuable to take into consideration both scientific and interpretative research on the effectiveness of PSD in assisting veterans with PTSD. This broad approach to the literature allows for insight into complexity of the topic. It sets the foundation for an understanding not only of specific measures of effectiveness, but also the conditions – personal, interpersonal and social – that can facilitate effectiveness. We turn now to the key themes that emerged from a review of the literature. The themes pertain specifically to PSD and veterans with PTSD but also set the context for further research that can improve our understanding of mental health concerns for current veterans, and what animals may be able to contribute to treatment. The literature review is structured this way with the intention of informing research that can directly influence policy and program development.

Benefits of PSD for Veterans with PTSD

One of the rationales for using PSD in the treatment of PTSD stems from research on the use of service animals to treat psychiatric symptoms in conditions like severe anxiety (Barker & Dawson, 1998; Mason & Hagan, 1999). Clinicians working in the area of mental health began to notice that people with PTSD also relied on their animals for support and care. In a commentary for the Annals of Clinical Psychiatry, Altschuler (1999: 29) writes

In many cases PTSD can prove notoriously resistant to treatment by either medications or therapy. A patient with PTSD recently told me that his anxiety was much increased at times when he had to be separated from his pet. Reflection on the patient’s comment has caused me to consider the idea that pet facilitated therapy (PFT) might be a useful adjuvant for treatment of PTSD.

In this research, the potential benefits of animals in the treatment and/or management of mental health was seen to fall along two broad spectrums. First is the distinction between direct and indirect benefits, and the second is benefits across the bio/psycho/social continuum. Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder Literature suggests that animals as companions, such as in AAT and AAI, are seen to have both direct and indirect effects on the management of mental health. Direct effects refer to improved markers of health, like reduced feelings of anxiety or blood pressure that result from partnering with a service or therapy animal (Morrison, 2007). Indirect effects are benefits that resulted from participation with animals, in everyday life and social interaction that can lead to positive health outcomes (Whitmarsh, 2005). This indirect benefit can also result from the bond generated between human and animal (Zilcha-Mano et al., 2011). Given the complexity of mental health and its management for individuals it is valuable to attend to a broad range of effects from animals, both immediate and ancillary, as indicated in relevant literature.

Research on animals and mental health also addresses benefits on a spectrum across the biological, psychological and social. In recognition of the limitations of a purely biomedical perspective, studies in the field of health over the last thirty years have expanded their scope to include psychological and social perspectives, as well as the relationship between the ‘biopsychosocial’ (Engel, 1977). While the subject of criticism, this model is conventionally considered a comprehensive model of understanding effects and effectiveness in a broad context (Davidson & Strauss, 1995). Studies of effectiveness in the realm of animals and mental health, and the effects of animals on health generally, can be organized around these three different levels of effect. Few studies have taken into consider all three, although there is a greater attention to not limiting the scope solely to biomedical markers of effectiveness in the case of animal interventions in health care.

The remainder of this section on benefits examines research on effectiveness at each of the three levels: biomedical, psychological and social. With the lack of research directly on PSD and veterans with post-traumatic stress disorder, each subsection frames evidence on that specific issue within the context of broader research on effectiveness in studies of animals and mental health broadly.


With greater attention to the use of animals as treatments in health care, more attention is also being devoted to understanding the physiological and biological responses that occur in humans as a result of their interactions with dogs, horses, and other companion species. A number of studies have been conducted on the release of neurochemicals resulting from human and animal encounters in a variety of contexts (Johnson et al., 2002). In an interesting experiment, Odendaal & Lehmann (2000), for instance, found that the neurotransmitter phenylethylamine – which can improve mood – is released in both the animal and the human during positive encounters between species. Similar research has examined changes in blood pressure and other conventional physiological markers of health in human animal encounters (Baun et al., 1984; Allen et al., 1991). Inquiry into the physiological dynamics across species opened up a general interest in more thoroughly exploring the potential measureable health benefits of AAT and AAI Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder programs and activities. However, there is debate about whether there is an actual direct animal effect (Straatman et al., 1997; Herzog, 2011). Clinical trials of AAT are an example of research planned and/or ongoing that seeks to give evidence of an animal effect as it occurs physiologically in general and specifically for people managing illness or seeking to improve health.

In the specific case of psychiatric service dogs and veterans with post-traumatic stress disorder, media and community organizations have made particular note of the positive physiological effects of interactions with service animals. In 2012, for instance, an article in the Smithsonian Magazine began with the headline, “How Dogs Can Help Veterans Overcome PTSD.” In this piece Colin (2012) describes new research findings that claim to show that partnering with a psychiatric service dog can release the hormone oxytocin, which can counter some of the symptoms associated with posttraumatic stress disorder. The challenge with this kind of public discourse is that it makes reference to research that is currently ongoing rather than published in scientific journals and is preliminary at best. Similar yet more indirect claims are made in the literature on PSD and PTSD among veterans. In a study of training programs, Yount and colleagues (2012) make an association between the use of oxytocin in the treatment of PTSD and research by Odendaal & Meintjes (2003) that show the neurophysiological effect of the bond between human and animals. While possible, as Yount et al. (2012) point out themselves, it is premature to make such claims without published evidence from research studies examining this relationship. The connection between animal interactions and hormones like oxytocin are still the subject of scholarly debate in ongoing research (Beetz et al., 2012). Beyond hormone and neurophysiology effects, using evidence from personal accounts in the media, Taylor (2013) notes that veterans do express a change in physiological response to trauma and stress pre- and post-service dog ownership. With the kinds of symptoms associated with PTSD there are opportunities in empirical scientific research to explore biomedical markers of illness management and improved health as a result of animal interactions. There are indications that this research is underway at several sites in the United States (Yount et al., 2012).


Literature on the psychological benefits of animals to human health is as expansive as it is extensive. In a review of literature on dogs, Wells (2007) discusses the range of research attesting to the contributions of canines to psychological well-being in addressing problems like anxiety and depression (Folse et al., 1994), and bolstering psychological resilience (Walsh, 2009; Beck & Katcher, 1983). These findings may contribute indirectly to positive psychological states in the form of, for instance, encouraging social interaction through physical activity (Toohey & Rock, 2011). The evidence for psychological benefits extends to the area animal assisted interventions and mental health concerns (Cirulli et al., 2011). Research on service dogs for instance shows they improve a range of psychological function and attitude indicators for people with physical and mental disabilities (Allen & Blascovich, 1996). There continues to be Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder questions regarding the methodological rigor of many studies on psychological well-being. However, whether benefits are defined narrowly in the reduction of specific symptoms or behavior or more generally in promoting a positive outlook, there is a growing body of evidence suggesting that dogs and animals generally contribute positively to managing mental health problems (Herzog, 2011; Fine, 2010).

The development of psychiatric service dogs emerged, in part, out of this recognition that animals in an assistance or therapeutic capacity can contribute to the psychological well-being of their human companions. Research on psychiatric service animals is sparse and constitutes a significant gap in the literature on the contribution of animals to managing illness and promoting health. An exception, in describing their role in psychiatric service, Tedeschi and colleagues (2010) set out broad parameters for the domain of psychiatric service animals. Drawing on work from Froling (2003) they identify the tasks of PSDs as, beyond emotional and psychological support (Lane et al., 1998), providing assistance in medical crises and with treatments, and also providing security. Additionally, drawing on Esnayra & Love (2008), they also identify the work done in engaging the human companion in cognitive behavior skills, in areas related to the dog’s natural ability, and in prompting strategies for self-regulation. In distinguishing between an emotional support animal, which do not receive specialized training, Tedeschi and colleagues (2010) emphasize that psychiatric service dogs do not simply help their human companions cope or provide them with support, but play a specified series of functions and forms of assistance that are attuned to the management of mental health. Further to this, Vredenburgh & Zackowitz (2012) make the point that unlike emotional support dogs, PSDs are recognized legally and given special rights to accompany their human companion and provide assistance and care.

Interestingly, similar to the physiological benefits that abound in public discourse, there are wide ranging claims in the media as to the psychological benefits of PSDs for veterans with PTSD, yet there exist few studies that confirm or refute such claims. Veterans who use a PSD to manage their PTSD reported that their psychological symptoms decreased as result of the assistance and support from their service animal (Esnyra & Love, 2008). Similarly, in a media analysis of self-reporting veterans, Taylor et al (2013) identified psychological benefits of PSD use on several levels: improvements in maladaptive emotional states; a greater ability to bond and trust; and a reduction of psychological symptoms overall. A study of PSD training programs by Yount et al., (2012) identified similar self-reporting benefits from veterans who were diagnosed with PTSD and were using a service animal as a means of managing their condition.

Stern and colleagues (2013) recently published findings from study they conducted on the benefits of companion animals for veterans with PTSD. While not about PSD directly, this research provides evidence that dogs do assist veterans in managing their mental health at a psychological level. The study indicates that veterans who adopted dogs experienced a decrease in symptoms associated with PTSD like anxiety, depression, isolation and concerns about security. Stern et al. (2013:568) conclude that their “results suggest that living with a companion Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder dog may help relieve some of the psychological distress associated with PTSD in some veterans.” Extrapolating from the study, it is very likely that PSD would play a similar function in the lives of veterans as did the adopted dogs.

The findings of research to date on PSD and PTSD are limited and rely entirely on self-reporting data from a small sample of veterans. However, studies on the contribution of animals in managing mental health indicate that there is evidence to suggest that service animals can make a contribution to the management of mental health problems at the level of alleviating psychological symptoms and increasing psychological resilience and capacity. Knisely & Barker (2012), for instance, show that there is evidence of psychological improvements among veterans who use AAI in non-military settings. Similarly, using data from survey and interviews, Wisdom et al. (2009) found that their use of service animals contributed to the capacity in recovering from mental illness and managing symptoms like anxiety (Barker & Dawson, 1998). The few studies cited here are examples of a much broader literature on service animals and the management of psychiatric and psychological symptoms resulting from mental illnesses like PTSD. This research helps to frame the limited evidence on PSD and the treatment of PTSD among veterans in a broader context and points to ways of moving forward with future research.


Literature on the social benefits of interactions with animals for human health is extensive (Serpell, 1991). Even within this field, studies specifically on the positive social effects of animals for the elderly, as an example, are far reaching in number. Companion species have been found to mitigate loneness and isolation (Garrity et al., 1989), help negotiate and facilitate interactions with care providers (Siegel, 1993) and improve overall quality of life (Siegel, 1990) among older adults. In much of this literature on social benefits locates the positive effect of animals as the indirect consequence of assistance and companionship (Edney, 1995). When exploring social phenomena, the parameters of the indirect influence on health can vary widely (Collis & McNicholas, 1998). In some instances the benefit is located at the level of everyday routines, as in the case of dog walking or the patterns and obligations of caring for animals (Knight & Edwards, 2008). Beyond the everyday, social benefits can extend to creating a bridge between the individual and broader public sphere, again in the case of a dog being a catalyst for social interactions at the park or in social settings (Cutt et al., 2007).

Studies that explore social benefits take a more interpretative research design when compared with research on the biomedical and psychological. While questioned as being less rigorous or empirically valid, research of this kind provide important insight in the social, cultural political and historical dimensions of effectiveness with regards to companion and service animals.

Attention to social benefits is evident in the limited published research on PSD and veterans with PSTD. The effects at the social level – community participation, destigmatization, and social Psychiatric Service Dogs and Veterans Living with Post-traumatic Stress Disorder interaction and membership – are substantiated in studies on the animals and their influence on managing mental health. Most prominent of social benefits of PSD was the bridge that was created to social arenas hence helping to counter feelings of isolation and seclusion. Psychiatric service dogs assisted in helping people leave their homes and enter into the public in a safe and secure manner (Yount, et al., 2012). This community participation is a resounding theme in studies of service dogs and their human partners, and is generally seen to foster a sense of social integration (Camp, 2001; Rintala et al., 2002). A related but distinct benefit from PSD was their contribution to improving social interaction and social membership. A good example of this is findings showing that the introduction of a dog or PSD improved social relations within family structures (Yount, et al., 2012; Beck et al., 2012). While at the level of personal testimonial in studies of veterans with PTSD, the positive influence of service dogs and pets on family relationships well documented in the literature (Lane, et al., 1998; Collins et al., 2006). A third social benefit of PSD was its perception as a non-stigmatizing therapeutic intervention (Taylor et al., 2013). It was seen by veterans, in addition to the public, as an acceptable form of therapy and therefore did not need to be hidden and had the potential to be discussed openly. As discussed by Taylor and colleagues (2013), there is a need for non-stigmatizing therapies for veterans with PTSD (McNally, 2012). The non-stigmatizing, and potentially de-stigmatizing qualities of animal-assisted interventions have been documented in the field, and are considered to be a key advantage of this approach (Velde et al., 2005).

Overall, taking into consideration the literature on the biological, psychological and social benefits there is evidence of effectiveness for animal assisted interventions in the area of managing mental health. The lack of research on PSD and posttraumatic stress disorder specifically poses limits on the whether it is also the case with veterans. When examining the intersections between the levels of effectiveness the ideas of improved well-being and quality of life are used to capture the benefit of companion animals, or service animals, in the lives of people who are managing mental health problems (Nordgren & Engstrom, 2014). While not easily quantifiable, in the case of conditions as complex and dynamic as PTSD, the operationalizing of concepts like well-being may be useful to identify and measure the intersecting benefits of animals as therapeutic modalities across the biological, psychological and social.

Using PSD as a Treatment

Animals are being used in a therapeutic capacity in increasingly diverse ways. The types of service animal used are increasing in number, as are their roles in managing illness and improving health. An issue raised by this trend is how to define the parameters for psychiatric dogs as a form of treatment. This theme was one that emerged in the literature on PSD and veterans with PTSD and in broader related studies. As a relatively new phenomenon, the concept of PSD as a treatment, like treatment modalities in general, is contested on several levels as this new practice is taken up by veterans with PTSD, their care givers and health care providers.

A key component of this issue is classifying what it is that PSD do for a person who is living with and managing a mental health problem. In the case of PTSD and veterans, Taylor et al., (2013) describe PSD as serving a number of functions: practical tasks usually associated with service dogs (turning on lights, finding keys), psychological and emotional support in stressful situations, and companionship at home and in social settings (Morris & Esnayra, 2011). Love and Esnayra (2009) go in more detail when describing their proposed study of symptom relief through PSD among veterans with PTSD. The role of PSD in their study includes physical tasks directed at both assisting veterans remember scheduled activities and accompany them in public spaces to helping them to manage emotional stressors and responses including suicide prevention. The conceptualization of PSD offered in initial studies moves the definition of a service dog beyond that of a device; moreover, the PSD becomes a means of alleviating symptoms, managing mental health problems and preventing future occurrences of responses and situations related to ongoing trauma, stress and anxiety. A PSD is a hybrid of device/treatment/companion/caregiver.

The assumption that PSD operate not only as a form of assistance but also as a treatment for psychological and mental health problems is reinforced in the broader literature. Studies of PSD among mental health patients in general claim that dogs do play a therapeutic role in a capacity akin to that of dogs and animals used in AAT (Esnayra & Love, 2008; reference). This finding is consistent with studies on the benefits of companion animals in general (Huss, 2009) and in the case of mental health specifically (Peacock, 2012). In studies of self-reported benefits, companion animals are found to be effective; however, more recent studies using a more narrow definition of health have found less evidence of actual changes in human health, as in lowering the risk of disease or decreasing the use of health care services (McNnicholas et al., 2005). The overall consensus to this point, if there is one at all, is that while there appears to be an ‘animal effect’ it can only be substantiated scientifically as a concept to be tested in further research rather than a fact in all cases (Herzog, 2011; Wells, 2009).

The issue of actual improvements in health versus perceived or indirect improvements in health as a result of companion animals or AAT continues to be a contentious issue (McNicholas, et al., 2005). Regardless of the debate on the relative merits (direct or indirect), animals are being increasingly medicalized and taken up as treatments or interventions or therapies in a variety of care and health care contexts (Willens, 2013). In the case of autism and childhood cancer there are efforts in place to conduct more rigorous clinical trials to advance the scientific evidence on the animal effect in different modalities and in different contexts (O’Haire, 2013). An interest in clinical studies as a means of further assessing the value of animals in human health is advancing particularly as a means of addressing mental health problems like anxiety, dementia, schizophrenia and trauma including PTSD (Peacock et al., 2012). This research will further position animals as treatments and also provide guidance as to their potential purpose in managing illness and promoting health. Evidence of this nature will be important to legitimating the use of animals in care, potentially, and serve to shift policy and resource allocation regarding their integration in formal forms of care giving and health care.

This research raises a number of important questions for the use PSD in the treatment of PTSD among veterans. First is whether the locus of therapeutic value for veterans is primarily in: companionship and its social effect; the therapeutic program surrounding the use of dogs (and equines) as in the case of AAT; or the assistance that is result of extensive training and expertise that are a feature of service dogs (Collins et al., 2006). In the case of PSD it is possible that, as treatment for PTSD, there is an effect from all three levels; this is a question that can only be answered through further empirical research (Huss, 2010). If the benefits of canines are primarily at the level of companionship it elevates the role of emotional support dogs as an alternative less expensive form of treatment at least for veterans who have less severe or debilitating symptoms from PTSD.

With regards to symptom management, a second question in considering PSD as a treatment is whether they serve as an adjunct treatment for conventional modalities, like counseling and medications, creating the conditions by which conventional treatments can be effective for a patient (Esnayra & Love, 2008). Or, whether it is possible, as has been suggested anecdotally at this point, that the PSD can be a treatment itself for PTSD; the dog serving to provide veterans with the assistance and support necessary for them to manage their illness without being reliant, partially or fully, on pharmaceuticals or other conventional treatments (Taylor et al., 2013). In a survey of veterans with PTSD, 40% reported having to use medications less often as a treatment as result of their partnering with a psychiatric service dog (Esnayra & Love, 2008). Each type of classification of canines as fulfilling a therapeutic function has wide reaching policy, legal ramifications for the use animals in health care generally and the use of PSD as a treatment for PTSD among veterans (Vredenburgh & Zackowitz, 2012).

Training, Placement and Regulation

Of the prominent themes emerging from literature on the use of animals in managing health, training, placement and regulation is treated seriously as an important component of effectiveness but is not in the foreground of many studies (Duncan, 1998). There are numerous issues raised about training and placement including, though not limited to, the selection process (Weiss, 1997) consistency in temperament (Svartberg et al., 2005) the ethical considerations of appropriately matching dogs with humans (Burrows et al., 2008) and ongoing training and education (Taylor et al., 2013). A related concern raised is the consistency of training across different contexts and the regulation or standardization of training and expertise among dogs (Danziel, 2003). Yet, despite this work, there does appear to be a disconnection between research on the use of animals in health care and research on the ongoing processes involved in their training and placement (Walsh & Merton, 1994).

Training and placement is taken up in the literature on PSD and the management of PTSD by veterans. A recurring theme is the importance of placement between an animal and a person in the effectiveness of the intervention in managing PTSD and mental health in general (Taylor, 2013; Zapf & Rough, 2002). Another prominent theme was on the nature of training programs and their organizations and development. Yount and colleagues (2012) analyze the development of PSD training program in the United States associated with a nonprofit organization. This description gives insight into the amount of work, effort and funds go into the training and placement process. As in this case, the training of psychiatric service dogs in general is a thorough process that can be very time-consuming (Furst, 2006). The entire procedure can take up to two years for animals with specific service assets (Dalziel et al, 2003). The cost of training PSDs is also high, and can cost up to USD $24,000 (Dalziel et al, 2003). In the United States or Canada, the training of these dogs is also a highly varied process, as there are currently no accreditation bodies to set standards for training (Modlin, 2012). Individual handlers and owners can also choose to train their own dogs (Modlin, 2012; Wisdom et al., 2009; Tedeschi, et al., 2010). Furthermore, the American Disabilities Act does not require individuals with service animals to carry training documentation with them (Modlin, 2012). This means that in some cases, individuals may successfully handle personal pets as service animals and not immediately be denied access. PSDs can also be trained to do very specific tasks, and are often trained specifically to assist with the unique needs of the individual (Esnayra & Love, 2008). In order to cut down on some of the costs that may be associated with carefully training dogs for specific tasks, some trainers have begun to train dogs from animal shelters and pounds (Weiss & Greenberg, 1997). There are also many prison-based animal programs (PAPs) in existence that involve inmates in the training of service animals (Furst, 2006). Although there are many clear advantages to using psychiatric service dogs, there are several challenges that must be addressed at the level of training, placement and regulation. In the United States, access laws pertaining to service animals exist at both local and state levels, creating a potential for conflicting regulations (Modlin, 2012). Additionally, under the American Disabilities Act, handlers and owners of service animals are not required to outfit their animals in vests or tags for identification (Modlin, 2012). While this provides owners with a certain level of choice and freedom concerning their animals, it may be difficult for business owners and law enforcement to decipher between service animals and pets. The cost of training and maintaining service animals is another challenge faced by handlers and trainers (Weiss & Greenberg, 1997). As mentioned above, some trainers have begun acquiring and working with dogs from shelters, but the costs may still be quite high (Weiss & Greenberg, 1997). Longitudinal studies assessing the cost-effectiveness of psychiatric service dogs appear to be lacking. The lack of accreditation and regulatory bodies may also create a challenge for those involved in the training process.