The study of service dogs for veterans with Post-Traumatic Stress Disorder: a scoping literature review

Can scent-detection dogs detect the stress associated with trauma cue exposure in people with trauma histories? A proof-of-concept study

Introduction

Post-traumatic stress disorder (PTSD) is an impairing mental health condition with high prevalence among military and general populations alike. PTSD service dogs are a complementary and alternative intervention needing scientific validation. We investigated whether dogs can detect putative stress-related volatile organic compounds (VOCs) in the breath of people with trauma histories (54% with PTSD) exposed to personalized trauma cues.

Methods

Breath samples were collected from 26 humans over 40 experimental sessions during a calm (control breath sample) and stressed state induced by trauma cue exposure (target breath sample). Two scent detection canines were presented with the samples in a two alternative forced choice (2AFC) discrimination and yes/no detection task. The 2AFC task assessed the dogs' ability to discriminate between the two states within the breath samples of one individual. The detection task determined their ability to generalize the target odour across different individuals and different stressful events of one individual. Signal Detection Theory was applied to assess dogs' sensitivity, specificity, precision, and response bias.

Results

The dogs performed at ∼90% accuracy across all sample sets in the discrimination experiment, and at 74% and 81% accuracy, respectively, in the detection experiment. Further analysis of dog olfactory performance in relation to human donor self-reported emotional responses to trauma cue exposure suggested the dogs may have been detecting distinct endocrine stress markers. One dog's performance correlated with the human donors' self-reported fear responses and the other dog's performance correlated with the human donors' self-reported shame responses. Based on these correlations between dog performance and donor self-report measures, we speculate that the VOCs each dog was detecting likely originated from the sympathetico-adreno-medullary axis (SAM; adrenaline, noradrenaline) in the case of the first dog and the hypothalamo-pituitary-adrenal axis (HPA; glucocorticoids) in the case of the second dog.

Conclusion

Our proof-of-concept study is the first to demonstrate that some dogs can detect putative VOCs emitted by people with trauma histories when experiencing distress theoretically associated with the intrusion and arousal/reactivity symptoms of PTSD. Results have potential to improve the effectiveness and training protocol of PTSD service dogs with a focus on enhancing their alert function.

A clinician's guide to the 2023 VA/DoD Clinical Practice Guideline for Management of Posttraumatic Stress Disorder and Acute Stress Disorder

A clinical practice guideline (CPG) is a rigorously established set of recommendations based on currently available evidence about the efficacy, safety, acceptability, and feasibility of interventions to assist with clinical decision-making. The 2023 Department of Veterans Affairs /Department of Defense Clinical Practice Guideline for Management of Posttraumatic Stress Disorder and Acute Stress Disorder is described herein. The CPG recommendations are accompanied by a clinical algorithm, which incorporates principles of evidence-based practice, shared decision-making, and functional and contextual assessments of goals and outcomes. An overview of the CPG recommendations is combined with a discussion of questions that clinicians and patients may face in implementing the CPG and suggestions for how to effectively work with the CPG.

Considerations for the Writing of Certification Letters Endorsing Use of Emotional Support Animals

Emotional support animals (ESAs) are different from service animals, therapy animals, and other disability-related assistance animals. Although pet ownership may confer psychological benefits, limited research has supported the use of ESAs to realize such benefits. If clinicians are asked to write a letter of support for use of an ESA, they need to be familiar with relevant federal, state, and local laws that regulate ESAs and with the essential components of an ESA evaluation. This article provides an overview of terminology; federal, state, and local laws related to ESAs; and clinical and ethical considerations for clinicians who decide to write these letters. The authors also review liability issues related to writing these letters, including those related to ESA aggression.

PTSD service dogs foster resilience among veterans and military families

Military deployment and reintegration challenges permeate the lives and relationships of Veterans, their spouses, and their families. Among these challenges, 23% of post-9/11 Veterans have been diagnosed with posttraumatic stress disorder (PTSD). Psychiatric service dogs have been found to help clinically alleviate PTSD symptoms when used as a complementary intervention. However, minimal research exists that explores the role of the service dog as a mechanism for cultivating resilience within the military family system. Researchers utilized a qualitative, constant comparative approach to analyze self-reported experiences of 101 individuals, including Veterans (n = 67) and their spouses (n = 34). Analyzed through the framework of the Theory of Resilience and Relational Load (Afifi et al., 2016), findings suggest complex communication processes that facilitate relational and family adaptation. These processes encompassed (a) the role of the service dog in building emotional reserves, (b) relational load introduced when caring for the service dog, and (c) the service dog's facilitation of relational maintenance behaviors among family members that contributed to communal orientation. Based on the results of this qualitative analysis, researchers suggest educational interventions where service dog trainers and mental health practitioners can incorporate relational maintenance strategies and family-focused approaches to integrating service dogs as military family members.

Effectiveness of Operation K9 Assistance Dogs on Suicidality in Australian Veterans with PTSD: A 12-Month Mixed-Methods Follow-Up Study

Post-traumatic stress disorder (PTSD) is a pervasive disorder among both current and ex-serving Australian Defence Force (ADF) members. Studies have shown current psychological and pharmacological treatments for PTSD are suboptimal in veterans, with high dropout rates and poor adherence to treatment protocols. Therefore, evaluating complementary interventions, such as assistance dogs, is needed for veterans who may not receive the ultimate benefit from traditional therapies. The present longitudinal mixed-method study examined the effectiveness of Operation K9 assistance dogs among sixteen veterans with PTSD, specifically, their effects on suicidality, PTSD, depression, and anxiety from baseline to 12 months post-matching. Self-reported measures were completed prior to receiving their dog (baseline) and at three time points (3, 6, and 12 months) following matching. The Clinician-Administered PTSD Scale for DSM-5 was used to assess the severity of every PTSD case. Veterans participated in a semi-structured interview 3 months post-matching. Whilst there was a reduction in the proportion of veterans reporting any suicidality, there was no significant change in the probability of veterans reporting suicidality between time points. There was a significant effect of time on PTSD, depression, and anxiety symptoms. Three major themes emerged from qualitative data analysis: life changer, constant companion, and social engagement. Qualitative data suggest assistance dogs can have a positive impact on important areas of daily life and support veterans in achieving some of the prerequisites for health, including access to services, transport, education, employment, and development of new and diverse social and community connections. Connections were key in improving health and wellbeing. This study exemplifies the power of human-animal relationships and adds emphasis to the need to take these seriously and create supportive healthy environments for veterans with PTSD. Our findings could be used to inform public health policy and service delivery, in line with the Ottawa Charter action areas and indicate that for veterans with PTSD, assistance dogs may be a feasible adjunct intervention.

The Impact of Service Dogs on Military Veterans and (Ex) First Aid Responders With Post-traumatic Stress Disorder

Due to its novelty and lack of empirical study it remains unclear if a service dog truly mitigates the burden of post-traumatic stress disorder (PTSD) symptoms. To cross sectionally investigate the effect of service dogs on veterans and first aid responders with PTSD, we studied subjective and physiological parameters in 65 individuals divided over four groups. These groups were: veterans and first aid responders with PTSD and a service dog (n = 20), with PTSD and a companion dog (n = 10), with PTSD without a dog (n = 12) and a group without PTSD (n = 23). We found that veterans and first aid responders with PTSD who had a service dog showed significantly less PTSD related symptoms, better sleep quality, and better wellbeing experience, than those with a companion dog. Those with a service dog additionally experienced fewer PTSD related symptoms than those without a service dog and tended to walk more than individuals without PTSD. No differences were found in cortisol levels between groups though and changes in both salivary cortisol and activity were not linked to improved welfare experience. Though the use of physiological measurement methods thus warrants more research, our study indicates that the subjective experience of wellbeing, sleep quality and PTSD related symptoms is improved by the presence of a service dog.

The Effect of Human-Horse Interactions on Equine Behaviour, Physiology, and Welfare: A Scoping Review

Simple Summary

Human–horse interactions (HHIs) are an important aspect of society, especially in the equine industry. HHIs are diverse and can be focused on horses as an economic means, pleasure, or companionship for humans. As a result, the welfare of horses during these interactions, including their mental and physical health, is an important consideration. Although the physical health of horses can be readily measured during equestrian activities, their mental health is more difficult to assess. This review was conducted to evaluate what is known about the horse’s mental state during common HHI in an attempt to better understand the welfare of the horse.

Abstract

Human–horse interactions (HHIs) are diverse and prominent in the equine industry. Stakeholders have an invested interest in making sure that HHIs are humane. Assessment of equine welfare goes beyond physical health and includes assessment of the emotional state of the animal. HHIs can have a permanent effect on human–horse relationships, thereby influencing welfare. Therefore, an understanding of the horse’s affective state during HHIs is necessary. A scoping review was conducted to: (1) map current practices related to the measurement of HHIs; (2) explore the known effects of HHIs on horse behaviour and physiology; and (3) clarify the connection between HHIs and equine welfare. A total of 45 articles were included in this review. Studies that used both physiological and behavioural measures of equine response to human interactions accounted for 42% of the included studies. A further 31% exclusively used physiological measures and 27% used behavioural observation. Current evidence of equine welfare during HHIs is minimal and largely based on the absence of a negative affective state during imposed interactions. Broadening the scope of methods to evaluate a positive affective state and standardization of methodology to assess these states would improve the overall understanding of the horse’s welfare during HHIs.

Do Service Dogs for Veterans with PTSD Mount a Cortisol Response in Response to Training?

Simple Summary

A growing number of people are supported by specialized service dogs. These dogs are highly trained to improve human welfare, yet not much is known about their own welfare. One of the ways in which welfare can be measured is through the expression of stress via the hormone cortisol. In this study, we investigated the level of cortisol in saliva, a measure for physiological stress, in 19 service dogs. We measured cortisol in the dogs’ saliva 15 min after arrival at a training ground, before partaking in a training session for service dogs, after participation in the training session, and after a 45-min free play period. We found no elevated levels of cortisol after the training session. Instead, we found that cortisol had lowered when compared to before the training. Additionally, we found that cortisol was highest 15 min after arriving at the training round and after 45 min of free play. This led to the conclusion that dogs in our study did not seem to have a stress response in response to participation in the training.

Abstract

Only a few studies have investigated the welfare of animals participating in animal-assisted interventions (AAIs). Most of these studies focus on dogs in therapeutic settings. There are, however, also dogs—service dogs—that are employed to continuously support a single human. Because the welfare of these service dogs is important for the sustainability of their role, the aim of this study was to investigate their stress response to service dog training sessions. To do this, we took repeated salivary cortisol samples from dogs who participated in a training session (n = 19). Samples were taken just after arrival at the training ground, before training, after training, and after a period of free play. Our results showed that mean cortisol levels in all samples were relatively low (between 1.55 ± 1.10 and 2.73 ± 1.47 nmol/L) compared to similar studies. Analysis further showed that samples taken before and after participation in the training’s session did not differ from one another. Mean cortisol levels in both situations were additionally lower than those upon arrival at the training site and after a period of free play. This led to the conclusion that the dogs in our study did not seem to experience training as stressful.

Effectiveness of animal-assisted interventions for children and adults with post-traumatic stress disorder symptoms: a systematic review and meta-analysis

Background: Animal-assisted interventions (AAI) are increasingly applied for people with post-traumatic stress disorder (PTSD) symptoms albeit its effectiveness is unclear.Objectives: To examine the effectiveness of AAI for treating PTSD symptoms.Method: We searched 11 major electronic databases for studies reporting quantitative data on effects of AAI for children and adults with PTSD symptoms. Of 22'211 records identified, we included 41 studies with 1111 participants in the systematic review comprising eight controlled studies with 469 participants in the meta-analysis. We conducted random-effects meta-analyses with all controlled studies based on standardized mean differences (SMD), and calculated standardized mean change (SMC) as effect sizes for studies with a pre-post one-group design. Two independent researchers assessed the quality of the included studies using the NIH Study Quality Assessment Tools. The primary outcome was PTSD or depression symptom severity measured via a standardized measurement at pre- and post-intervention assessments.Results: There was a small but not statistically significant superiority of AAI over standard PTSD psychotherapy (SMD = -0.26, 95% CI: -0.56 to 0.04) in reducing PTSD symptom severity while AAI was superior to waitlist (SMD = -0.82, 95% CI: -1.56 to 0.08). Getting a service dog was superior to waiting for a service dog (SMD = -0.58, 95% CI: -0.88 to -0.28). AAI led to comparable effects in reducing depression as standard PTSD psychotherapy (SMD = -0.03, CI: -0.88 to 0.83). Pre-post comparisons showed large variation for the reduction in PTSD symptom severity, with SMCs ranging from -0.38 to -1.64, and for depression symptom severity, ranging from 0.01 to -2.76. Getting a service dog lowered PTSD symptoms between -0.43 and -1.10 and depression with medium effect size of -0.74.Conclusions: The results indicate that AAI are efficacious in reducing PTSD symptomatology and depression. Future studies with robust study designs and large samples are needed for valid conclusions.

Service Dogs for Veterans and Military Members With Posttraumatic Stress Disorder: Replication With the PTSD Checklist for DSM-5

Psychiatric service dogs are an emerging complementary intervention for veterans and military members with posttraumatic stress disorder (PTSD). Recent cross-sectional studies have documented significant, clinically relevant effects regarding service dogs and PTSD symptom severity. However, these studies were conducted using the PTSD Checklist (PCL) for the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). The present study aimed to replicate and advance these findings using the latest version of the PCL for the fifth edition of the DSM (PCL-5). Participants included 186 military members and veterans who had received a PTSD service dog (n = 112) or who were on the waitlist to receive one in the future (n = 74). A cross-sectional design was used to investigate the association between having a service dog and PCL-5 total and symptom cluster scores. After controlling for demographic variables, there was a significant association between having a service dog and lower PTSD symptom severity both in total, B = -14.52, p < .001, d = -0.96, and with regard to each symptom cluster, ps < .001, ds = -0.78 to -0.94. The results replicated existing findings using the largest sample size to date and the most recent version of the PCL. These findings provide additional preliminary evidence for the efficacy of service dogs as a complementary intervention for military members and veterans with PTSD and add to a growing body of foundational research serving to rationalize investment in the further clinical evaluation of this emerging practice.

A One Health Perspective on the Human-Companion Animal Relationship with Emphasis on Zoonotic Aspects

Over time the human-animal bond has been changed. For instance, the role of pets has changed from work animals (protecting houses, catching mice) to animals with a social function, giving companionship. Pets can be important for the physical and mental health of their owners but may also transmit zoonotic infections. The One Health initiative is a worldwide strategy for expanding collaborations in all aspects of health care for humans, animals, and the environment. However, in One Health communications the role of particularly dogs and cats is often underestimated.

OBJECTIVE

Evaluation of positive and negative One Health issues of the human-companion animal relationship with a focus on zoonotic aspects of cats and dogs in industrialized countries.

METHOD

Literature review.

RESULTS

Pets undoubtedly have a positive effect on human health, while owners are increasing aware of pet's health and welfare. The changing attitude of humans with regard to pets and their environment can also lead to negative effects such as changes in feeding practices, extreme breeding, and behavioral problems, and anthropozoonoses. For the human, there may be a higher risk of the transmission of zoonotic infections due to trends such as sleeping with pets, allowing pets to lick the face or wounds, bite accidents, keeping exotic animals, the importation of rescue dogs, and soil contact.

CONCLUSIONS

One Health issues need frequently re-evaluated as the close human-animal relationship with pet animals can totally differ compared to decennia ago. Because of the changed human-companion animal bond, recommendations regarding responsible pet-ownership, including normal hygienic practices, responsible breeding, feeding, housing, and mental and physical challenges conforming the biology of the animal are required. Education can be performed by vets and physicians as part of the One Health concept.