Quantifying the Efficacy and Role of Service Dogs for Military Veterans With PTSD
Phase: NA
Conditions: Post Traumatic Stress Disorder
Sponsor: University of Arizona

Study Title: Quantifying the Efficacy and Role of Service 
Dogs for Military Veterans With PTSD 
 
Sponsor: Dr. Marguerite E. O’Haire 
 
ClinicalTrials.gov ID: NCT03245814 
 
Document date: July 20, 2023 
 
 
 

Brief Summary 
The purpose of this study is to quantify the therapeutic efficacy and role of trained service dogs on socio-
emotional functioning among military veterans with posttraumatic stress disorder (PTSD). 
 
Detailed Description 
The long-term research goal is to evaluate the safety and efficacy of service dogs as a complementary 
intervention to enhance biopsychosocial functioning in special populations. The objective is to conduct a 
methodologically rigorous trial to quantify the therapeutic efficacy of service dogs on clinically important outcomes 
for veterans with PTSD. Based on preliminary findings and qualitative reports, the central hypothesis is that military 
veterans with PTSD who are provided service dogs will experience reduced PTSD symptoms related to socio-
emotional functioning and arousal modulation. The rationale for this research is that its successful completion will 
provide an evidence-based demonstration of the efficacy and role of an increasingly used yet poorly tested 
complementary intervention. The completion of this project is expected to establish an initial demonstration of the 
therapeutic efficacy of service dogs in this population, as well as possible mechanisms of action via specific biological 
pathways and human-canine interaction profiles. 
Conditions: Posttraumatic Stress Disorder (PTSD) 
Intervention / Treatment: Behavioral: Service Dog 
 
Funding 
This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human 
Development (NICHD) and the National Center for Complementary and Integrative Health (NCCIH) of the National 
Institutes of Health (NIH) under award number R21HD091896, Merrick PetCare and the Dogtopia Foundation. The 
content is solely the responsibility of the authors and does not necessarily represent the oﬃcial views of the National 
Institutes of Health. 
 
Participant Criteria 
Eligibility Criteria 
Inclusion criteria for veterans into the study will include: 
• 
Applied for and approved to receive a dog from K9s For Warriors 
• 
Military service on or after September 11, 2001 
• 
Honorable discharge or current honorable service 
• 
Diagnosis of PTSD 
• 
No conviction of any crimes against animals. 
• 
18 Years and older  
 
Study Plan 
Study Design 
Primary Purpose: Supportive Care 
Allocation: Non-Randomized 
Interventional Model: Parallel Assignment 
Masking: Single (Outcomes Assessor) 
Masking Description: Clinician Administered PTSD Scale for DSM-V (CAPS-5) assessments will be completed via 
telephone by a trained CAPS-5 rater who will be masked to the intervention and treatment arm of each participant. 
Arms and Interventions 
Participant / Group Arm 
Intervention / Treatment 
Experimental: Service Dog 
Participants in the service dog arm will receive unrestricted, 
non-study usual care, in addition to a trained service dog. 
Behavioral: Service Dog 
A service dog trained to perform tasks that are 
specific to PTSD 
No Intervention: Waitlist Control 
Participants in the control arm will receive unrestricted, non-
study usual care, while on the waitlist for a service dog. 
 
 
Outcome Measures 
 

Primary 
 
Outcome Measure 
Measure Description 
Time Frame 
PTSD severity 
and symptoms via 
self-report 
Posttraumatic Stress Disorder Checklist for DSM-V (PCL-5) 
3 months 
PTSD severity 
and symptoms via 
clinician rating 
Clinician-Administered PTSD Assessment for the Diagnostic and 
Statistical Manual of Mental Disorders, Fifth Edition DSM-V (CAPS-5) 
3 months 
Depression 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v1.0 - Emotional Distress - Depression 8a 
3 months 
Anxiety 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v1.0 - Emotional Distress - Anxiety 8a 
3 months 
 
Secondary 
 
Outcome Measure 
Measure Description 
Time Frame 
Social isolation 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v2.0 - Social Isolation 8a 
3 months 
Companionship 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v2.0 - Companionship 6a 
3 months 
Ability to 
participate in 
social activities 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v2.0 - Ability to Participate in Social Roles and 
Activities 8a 
3 months 
Mental health 
quality of life 
Veterans Rand 12-item Health Survey (VR-12) - Mental Health 
Component 
3 months 
Psychological  
well-being 
Bradburn Scale of Psychological Wellbeing (BSPW) 
3 months 
Life satisfaction 
Satisfaction with Life Scale (SLS) 
3 months 
Resilience 
Connor-Davidson Resilience Scale (CDRS) 
3 months 
Anger 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v1.1 - Emotional Distress - Anger 5a 
3 months 
Daily socio-
emotional 
experiences 
Ecological momentary assessment (EMA) 
3 months 
 
Other Pre-specified 
 
Outcome Measure 
Measure Description 
Time Frame 
Work and activity 
participation 
Work Productivity and Activity Impairment Questionnaire (WPAIQ) 
3 months 
Suicidal ideation 
Columbia Suicide Severity Rating Scale (CSSRS) 
3 months 
Sleep quality 
Pittsburgh Sleep Quality Assessment (PSQI) 
3 months 
Sleep disturbance 
Patient Reported Outcome Measurement Information System (PROMIS) 
Adult Short Form (SF) v1.0 - Sleep Disturbance 8a 
3 months 
Sleep actigraphy 
Actiwatch 2 (Philips Respironics) 
3 months 
Salivary cortisol 
awakening 
response 
Passive drool method (Salimetrics) 
3 months 
Electrodermal 
activity (skin 
conductance) 
Embrace wristband (Empatica, Inc.) 
3 months 
 

Collaborators and Investigators 
Sponsor: Marguerite O'Haire 
 
Collaborators  
• 
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) 
• 
National Center for Complementary and Integrative Health (NCCIH) 
 
Investigators  
• 
Principal Investigator: Marguerite O'Haire, Ph.D.,Purdue University 
 
Statistical Analysis Plan 
Since all the outcome measures are ordinal in nature (based on questionnaire scores), cumulative probability 
models will be used for all outcomes. While many of these outcomes have been modeled with linear regression in past 
studies, statisticians have cautioned that treating ordinal data as though they were continuous could potentially lead to 
misleading results, and that even continuous data can be modeled with cumulative probability models to avoid 
assumptions about the conditional distribution of the outcome (1,2). Cumulative probability models enable estimation 
of effect ratios (e.g., veterans allocated service dogs had a lower odds of greater CAPS-5 score compared to veterans 
on the waiting list), exceedance probabilities (e.g. Prob[PHQ-9 ≥ 10 | X=service dog]), and differences in exceedance 
probabilities (e.g. absolute risk reduction between veterans allocated a service dog vs control). 
In addition to a binary variable for intervention (1=service dog, 0=control), covariates will include the baseline 
value of the modeled outcome, age, gender/sex, concurrent evidence-based treatment for PTSD, pet ownership, 
military sexual trauma, and traumatic brain injury. 
We will conduct sensitivity analyses, modeling the primary outcomes with ordinary least squares regression to 
see if our conclusions are sensitive to the model choice, by comparing the estimated conditional means and 95% 
confidence intervals. 
In exploratory analyses, we will consider a potential interaction between treatment and baseline PTSD severity, 
as baseline severity could modify the effect of service dog. 
Multiple imputation will be used for missing covariate data and missing data at the 3-month follow-up visit. 
 
Software 
R package rms (orm function) or rmsb package (blrm function) 
 
Reporting 
1. Estimated conditional median (or mean) (e.g., conditional mean PCL-5 given service dog, and given no 
service dog), with nonparametric bootstrap 95% confidence intervals; adjusted for pre-specified covariates. 
2. Estimated parameter comparing service dog group to no service dog group (e.g. odds ratio for logit link) with 
nonparametric bootstrap 95% confidence interval; adjusted for pre-specified covariates. 
3. For established clinically important cutoffs, exceedance probabilities (Prob[Y ≥ y | X]) will be reported (e.g., 
Prob[PHQ-9 ≥ 10 | X=service dog]), and differences in exceedance probabilities with nonparametric 
bootstrap 95% confidence intervals; adjusted for pre-specified covariates. 
 
References 
1. Liddell, T. M., & Kruschke, J. K. (2018). Analyzing ordinal data with metric models: What could possibly 
go wrong?. Journal of Experimental Social Psychology, 79, 328-348. 
2. Liu, Q., Shepherd, B. E., Li, C., & Harrell Jr, F. E. (2017). Modeling continuous response variables using 
ordinal regression. Statistics in medicine, 36(27), 4316-4335.