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. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Anthrozoos. 2021 Apr 23;34(3):393–406. doi: 10.1080/08927936.2021.1898219

The Effect of a PTSD Service Dog on Military Veterans’ Medication Regimens: A Cross-Sectional Pilot Study

Kerri E Rodriguez a, Lindsey M Anderson b, Carol A Ott b, Marguerite E O'Haire a
PMCID: PMC8204643  NIHMSID: NIHMS1701257  PMID: 34140755

Abstract

Recent research suggests that service dogs may have clinically-relevant benefits for military veterans with posttraumatic stress disorder (PTSD). However, the effects of PTSD service dogs on veterans’ medication use has been largely unexplored. The objective of this study was to quantify the effect of PTSD service dogs on medication use among a population of military veterans with PTSD. In a cross-sectional design, United States post-9/11 military veterans with PTSD were recruited from a single service dog provider including veterans living with a PTSD service dog (n = 52) and veterans on the waitlist (n = 44). Both populations of veterans received treatment as usual. Participants completed an online survey of self-reported medication regimens and medication changes. Regression models quantified the effect of having a service dog on physical health, mental health, pain, and sleep medications while controlling for confounding variables (age, sex, relationship status, traumatic brain injuries, and physical health). Results indicated that there were no significant effects of having a service dog on overall self-reported medication use nor any specific medication category (p’s > 0.06). However, veterans with a service dog were more likely than those on the waitlist to report that their doctor had decreased dosage or removed medications since getting their service dog. The results of this preliminary cross-sectional research should be interpreted with caution, as future within-subject and pharmacy-verified research is necessary to understand the causality of these findings.

Keywords: human–animal interaction, pharmacotherapy, posttraumatic stress disorder, PTSD, service dogs, veterans

Posttraumatic stress disorder (PTSD) is a trauma- and stressor-related disorder that impacts up to 23% of post-9/11 United States service members and veterans deployed to Afghanistan and Iraq (Fulton et al., 2015). Recommended treatments for military veterans with PTSD largely consist of pharmacotherapy and psychotherapy (US Department of Veterans Affairs/US Departent of Defense Management of Post-Traumatic Stress Disorders Working Group, 2017). However, many military members and veterans affected by PTSD do not seek mental health care (Hoge et al., 2014) and of the evidence-based pharmacotherapy and psychotherapy treatments available, high dropout and/or non-response rates are commonly observed (Hoge et al., 2014; Najavits, 2015; Zohar et al., 2002). Many individuals with PTSD who respond to evidence-based treatments in the short-term do not reach stable remission over time (Katz et al., 2011). In addition, common comorbid conditions such as depression, anxiety, traumatic brain injury, or substance use disorder can make treatment for military veteran with PTSD more difficult (McCauley et al., 2012; Richardson et al., 2017; Sayer et al., 2009). Thus, many alternative and complementary interventions for PTSD have emerged to assist military members and veterans in managing their daily PTSD symptoms (Libby et al., 2013).

One increasingly popular complementary intervention to supplement evidence-based treatment for PTSD are psychiatric service dogs that are specifically trained and placed with individuals with PTSD, called PTSD service dogs (Walther et al., 2017). These PTSD service dogs are specifically trained for tasks related to a PTSD disability, allowing them legal protection and public access under civil rights laws for individuals with disabilities in the United States and many other countries (e.g., Americans with Disabilities Act of 1990; Equality Act of 2010). In a public setting, PTSD service dogs are trained for a variety of positional commands that are thought to instill a sense of safety and decrease hypervigilance in crowds (Rodriguez et al., 2020). PTSD service dogs can also be trained to both alert to and distract an individual from anxiety or emotional distress (Rodriguez et al., 2020). Specifically, dogs are often trained to lick, nudge, or apply pressure with their body when an individual is in distress either during the day or at night when disrupting nightmares. These alert and response behaviors are intended to provide an individual with PTSD a sense of calming relief and an anchor to the present moment to distract from the experienced distress. In combination with standard PTSD treatments, PTSD service dogs may be a promising complementary intervention with low associated stigma among military veterans with PTSD (Lessard et al., 2018).

Preliminary cross-sectional and short-duration longitudinal studies suggest a significant positive effect of PTSD service dogs on PTSD symptoms, mental health, social health, and quality of life as an complementary intervention to treatment as usual (Krause-Parello et al., 2016). Cross-sectional studies have found that after controlling for key confounding variables, military veterans with a PTSD service dog report significantly and clinically lower PTSD symptoms, less depression and anxiety, and less sleep disturbance than control groups on the waitlist to receive a service dog (e.g., O'Haire & Rodriguez, 2018; Rodriguez et al., 2018; Yarborough et al., 2017). Longitudinal studies accounting for veterans’ baseline functioning suggest clinically significant decreases in PTSD symptoms as well as improvements to mental health and social and relational functioning (e.g., Bergen-Cico et al., 2018; Whitworth et al., 2019). However, research suggests PTSD service dogs are not a standalone cure for military veterans’ PTSD, but rather a complementary intervention that may improve specific areas of functioning (Bergen-Cico et al., 2018; O'Haire & Rodriguez, 2018; Yarborough et al., 2017). Qualitative studies report that many veterans attribute their service dogs as a factor in reducing or discontinuing medications for daily mood, mental and physical health, or sleep (Krause-Parello & Morales, 2018; Lessard et al., 2018; Yarborough et al., 2018). Not only do veterans describe how the service dog’s calming behaviors contribute to less reliance on anxiety medications both at home and in public, but also report that the service dog’s comfort and nightmare disruption behaviors at night help reduce reliance on sleep medications (Krause-Parello & Morales, 2018; Lessard et al., 2018; Yarborough et al., 2018).

However, apart from qualitative reports, the effect of PTSD service dogs on veterans’ medication use has been largely unexplored. A 2020 exploratory case study tracked prescribed medication use among four veterans one year prior to and one year after their match with a service dog, finding that all four veterans either stabilized or decreased their use of prescription medications for anxiety, sleep, and mood stabilization post-service dog (Husband et al., 2020). However, the small sample size of this case study limits any strong conclusions. A 2017 study compared the self-reported use of psychiatric medications across 24 military veterans with a PTSD service dog and 54 on the waitlist to receive one, but did not find a significant group effect on medication use (Yarborough et al., 2017). However, the study did not look at use within sub-classes of medications and did not statistically control for key confounding demographics. There remains a critical need to assess the effect that a PTSD service dog can have on medication use across specific domains, including physical health, mental health, pain, and sleep. Continued empirical research on the clinically-relevant effects of PTSD service dogs for military veterans with PTSD is imperative to inform practicing clinicians and providers on what to expect from this increasingly popular complementary intervention option. Additionally, as research on the effects of PTSD service dogs reaches the rigor of randomized controlled trials (ClinicalTrials.gov, 2019a, 2019b), there is an increased need to understand the potential mechanisms by which PTSD service dogs may improve veterans’ health and wellbeing. These mechanisms may be partially informed by understanding changes to veterans’ medication regimens.

The objective of this cross-sectional pilot study was to evaluate the effect of the placement of a PTSD service dog on United States post 9/11 military veterans pharmacotherapies via self-reported medication regimens. The clinical importance of this study is to provide critically needed preliminary quantification of the effects of PTSD service dogs on anxiety, depression, and PTSD-related medications among military veterans with PTSD. The hypothesis of this study was that compared to a control group of veterans with PTSD who are on the waitlist to receive a service dog, veterans with a service dog will report taking overall less medication, including less medications for physical health, mental health, pain, and sleep.

Methods

Participants

Participants were recruited from a database of individuals who had applied for and been accepted to receive a service dog from United States service dog provider K9s For Warriors. Participants included both those who had previously received a service dog from the provider (service dog group) as well as those who had been approved to receive a service dog, but had not received one yet (waitlist group). Individuals on the waitlist were expected to receive a service dog in the future, unless they voluntarily withdrew from the program. Per the provider’s inclusion criteria for being approved to receive a service dog, all participants had military service after September 11, 2001 with honorable discharge or current honorable service, no current substance misuse or conviction of any crime against animals, and a confirmed diagnosis of PTSD at the time of applying for a service dog. PTSD diagnoses were confirmed by either a community diagnosis via a letter signed by a medical or mental health professional or receiving a self-reported score greater than 50 on the PTSD Checklist (PCL-C; Weathers et al., 1993) at the time of applying to receive a service dog. Both participants on the waitlist and with a service dog had unrestricted access to usual medical care of their choice and were not encouraged by the provider or the research team to engage in or discontinue any specific treatment or medication for their PTSD.

Service dogs were trained for tasks that address PTSD symptomology, including alerting to anxiety, providing distraction from an intrusion episode, and waking from nightmares. Dogs also are taught positional commands in public in which the dog stands in front of the veteran to help provide personal space from others (“block”) and stands behind the veteran to look the other direction and provide a sense of safety (“cover”). Service dogs were primarily Labrador Retrievers, Golden Retrievers, and Mixes and were primarily sourced from local shelters.

Procedures

The study was approved by the Purdue University Human Research Protection Program Institutional Review Board (IRB Protocol #1504015973). No interactions occurred between the research team and service dogs, thus a waiver was obtained from the Purdue University Animal Care and Use Committee. Participants were recruited between November 2015 and February 2016. After obtaining demographic information from the service dog provider, researchers sent all potential participants a study packet in the mail which consisted of participation materials and $20 cash as remuneration for time spent reviewing materials. Following voluntary informed consent, participants completed an online or mail-in survey consisting of a battery of standardized, self-report measures. Upon completion of the survey, participants received an additional $20 for survey participation. Data from the remainder of the online survey has been previously published (O’Haire & Rodriguez, 2018).

Measures

By consenting to participate in the cross-sectional survey, participants allowed researchers access to their files on record with the service dog provider, which contained demographic variables such as date of birth and sex. The cross-sectional survey collected further demographic and clinical information on current relationship and employment status as well as if participants were currently receiving treatment for PTSD at the time of the study (independent of having a service dog) and the frequency in which they engage in treatment.

PTSD symptom severity was assessed with the PTSD Checklist (PCL-C; Weathers et al., 1993) based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed; DSM–IV). Respondents were asked to self-rate 17 PTSD symptoms from 1 (“not at all”) to 5 (“extremely”) to indicate the degree to which they have been bothered by each symptom over the past month. Scores range from 17 to 85, with higher scores indicative of greater PTSD symptom severity and a score above 50 indicating a positive screening for PTSD (Forbes et al., 2001). As a covariate, physical health was measured with the Veterans RAND 12-item health survey (VR-12; Iqbal et al., 2007) physical component score (PCS), which is a measure of general health, physical functioning and role playing, and bodily pain. PCS summary scores were standardized using a t-score transformation which is normed to a US population score of 39.82 and a standard deviation of 12.20 (Selim et al., 2009).

To assess current medication use, participants were asked: “Since getting a service dog/getting on the waitlist, has your doctor made any changes to your medications? Select all that apply” with checkboxes for the following categories: No, no changes; Yes, increased dose; Yes, added a medication; Yes, decreased dose; Yes, removed a medication. Participants were also asked to: “Please list all medications you currently take and the reason for their use (Format- Medication: Use)” with a blank list for up to 25 entries.

Medication Coding

A member of the research team quantified and coded each listed medication per the veteran’s stated use for the medication. Many medications veterans listed were versatile in that they were used for differing off-label uses according to an individual veteran’s needs, as is common in pharmacotherapy for PTSD (Berger et al., 2009; Raskind, 2009). Thus, the same medication could be coded into different sub-categories depending on each participant’s self-reported reason for taking it (e.g., one veteran may report taking Clonidine for hypertension, while another veteran may report taking Clonidine as a sedative for falling asleep). If a veteran stated two reasons for taking a medication that overlapped in more than one sub-category (e.g., Topiramate for sleep and migraines; Duloxetine for depression and neuropathic pain), the medication was coded into both relevant sub-categories (total of n = 19 medication entries).

Final coded data was organized into four categories, each with subcategories. Participants received either a 0 (absence) or 1 (presence) of taking a medication in each medication sub-category and category. Physical health included hypertension medications (e.g., alpha and beta blockers, central alpha agonist, angiotensin converting enzyme inhibitors, diuretics, angiotensin receptor blockers) and medications for migraines/headaches (e.g., Midrin®, Excedrin®, triptans, anticonvulsants, non-steroidal anti-inflammatory drugs (NSAIDs). The mental health category included short-acting anxiety medications (e.g., benzodiazepines, beta blockers, azapirones), antidepressants (e.g., selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, norepinephrine–dopamine reuptake inhibitors, tetracyclic/tricyclic antidepressants, novel antidepressants) and antipsychotics (atypical antipsychotics, mood stabilizers). The pain category included narcotic pain medications, non-narcotic prescription pain medications (e.g., nerve blockers, muscle relaxers, anticonvulsants, prescription NSAIDs), and non-narcotic over-the-counter (OTC) pain medications (e.g., acetaminophen, OTC NSAIDs, topical pain relievers). The sleep category included general sleep medications (e.g., sedative-hypnotics, melatonin receptor agonists, antidepressants, antihistamines, anticonvulsants used at night for sleep) and medication for nightmares (prazosin).

Data Analysis

Statistical analyses were performed using SPSS Version 22. To examine group differences in changes to medications, independent t-tests were conducted. To examine the effect of having a service dog on medication use in each sub-category, a series of logistic regression models were performed. The independent variables were each sub-category and predictor variables consisted of having a service dog or not (1 = service dog, 0 = waitlist) as well as the demographic variables of age (continuous), sex (1 = male, 0 = female), relationship status (1 = married or cohabitating, 0 = not married or cohabitating), presence of a comorbid traumatic brain injury (TBI) diagnosis (1 = yes, 0 = no), and physical health (VR-12 physical component score; continuous). Each of these covariates were chosen due to both their theoretical value of impacting medication use as well as their statistical value in explaining at least one sub-category medication at a level of p < 0.10.

Results

Of the 304 individuals contacted, 141 completed at least 50% of the online survey, of which 129 completed the medication portion of the survey (including 67 placed with a service dog and 62 on the waitlist to receive one). Participants with a service dog had their dogs an average of 1.64 ± 1.09 years (range of 1 month to 4 years) at the time of surveying while those on the waitlist had been waiting an average of 0.64 +/− 0.36 years. Participants were 38.99 ± 8.47 years old, mostly male (101/129, 78%), unemployed (92/129, 71%), and had received some college education (86/129, 67%). Groups did not differ in any demographic characteristics (all p’s > .230), with the exception that participants with a service dog were more likely to be married or cohabitating with a romantic partner (service dog: 59/67, 88%, waitlist: 44/62, 71%; χ2 = 5.846, p = 0.016; relationship status was included as a covariate in all models). There was no group difference in physical health (PCS service dog M = 36.09 ± 10.53; waitlist M = 35.62 ± 13.59; t = 0.220, p = 0.826). Groups did not statistically differ in whether participants were currently receiving treatment for PTSD (service dog: 55/67, 82%, waitlist: 51/62, 82%), nor did they differ in the frequency in which they engaged in evidence-based, complementary, or alternative treatments (service dog: M = 41.47 ± 79.27 sessions per year, waitlist: M = 38.10 ± 37.49 sessions per year). Participants with a service dog self-reported significantly less PTSD symptom severity on the PCL-C than those on the waitlist (service dog M = 66.32 ± 11.69; waitlist M = 58.33 ± 12.97; t = −3.667, p < 0.001), with both groups reporting average scores above the clinical cutoff of 50.

Table 1 displays results from the question “Since getting a service dog or getting on the waitlist, has your doctor made any changes to your medications? Select all that apply.” Participants on the waitlist were more likely to report that they had experienced no changes (p = 0.012) or an increased dose (p = 0.013) in their medications than those with a service dog. There was no significant group difference (p = 0.905) in the frequency of those reporting a new medication had been added to their regimen. Finally, participants with a service dog were more likely to report that they had experienced a decreased dose or removed a medication (p’s < 0.001) than those on the waitlist.

Table 1.

Descriptives statistics and group-level analyses on responses to the question “Since getting a service dog/getting on the waitlist, has your doctor made any changes to your medications? Select all that apply.”

Waitlist
(n = 62)		 Service dog
(n = 67)		 Group
difference
n (%) n (%) χ2 p
No changes 31 (50%) 19 (28%) 6.354 0.012
Increased dose 22 (36%) 11 (16%) 6.149 0.013
Added a medication 17 (27%) 19 (28%) 0.014 0.905
Decreased dose 1 (2%) 25 (37%) 25.503 < 0.001
Removed a medication 7 (11%) 30 (45%) 17.652 < 0.001
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A total of 44/67 (66%) participants with a service dog and 52/62 (84%) participants on the waitlist listed at least one medication they were currently taking; the remaining participants did not list any medications (n = 33). Veterans on the waitlist were significantly more likely to provide at least one medication they were taking (χ2 = 5.602, p = 0.018), but there were no differences in demographic variables, physical health, or PTSD severity among those who provided information versus those who did not (all p’s > 0.070). Of the participants who reported at least one medication (n = 96), participants listed an average of 6.87 medications (SD = 4.42) including both prescription and over-the-counter medications. Groups did not significantly differ in the total number of medications reported (service dog M = 6.59, SD = 4.03; waitlist M = 7.11 SD = 4.76; t = −0.577, p = 0.565). There was no significant relationship between PTSD symptom severity and total medications reported across the full sample (r = 0.068, p = 0.508) nor within the service dog (r = −0.07, p = 0.647) or waitlist groups (r = 0.154, p = 0.275).

Table 2 displays both the frequencies of coded medication by group as well as logistic regression results examining the effect of having a service dog on reporting. In the physical health category, roughly 44% of the sample reported taking medications for blood pressure and/or migraines. There was no significant effect of having a service dog on the reporting of taking blood pressure or migraine medication (p’s > .234). Regarding mental health medications, a majority of the sample (92%) reported taking antipsychotic, short-acting anxiety, and/or antidepressant medications. After controlling for covariates, there was no significant effect of having a service dog on any of these medication categories (p’s > 0.425). More participants on the waitlist reported taking sleep medications for general sleep and/or nightmares than those with a service dog (77% vs 59%). However, after controlling for covariates there was no significant effect of having a service dog on either general sleep or nightmare medication, although both significance values were low (p < 0.061 and p < 0.067, respectively). Regarding pain medications, roughly half the sample reported taking narcotic, non-narcotic, and/or over-the-counter pain medications. After controlling for covariates, there was no relationship between having a service dog and narcotic, non-narcotic, and/or over-the-counter pain medications (p’s > 0.591).

Table 2.

Descriptive statistics and group-level analyses on self-reported medication use across categories.

Waitlist
(n = 52)		 Service dog
(n = 44)		 Group
difference
n (%) n (%) B p
Physical Health 23 (44%) 19 (43%)
 Blood pressure 14 (27%) 9 (20%) −0.588 0.274
 Migraines 14 (27%) 13 (30%) 0.245 0.609
Mental Health 48 (92%) 40 (91%)
 Antipsychotics 13 (25%) 8 (18%) −0.462 0.373
 Short-acting anxiety 25 (48%) 22 (50%) 0.013 0.975
 Antidepressants 45 (87%) 37 (84%) −0.505 0.425
Sleep 40 (77%) 26 (59%)
 General sleep 36 (69%) 22 (50%) −0.818 0.061
 Nightmares 19 (37%) 9 (21%) −0.914 0.067
Pain 28 (54%) 26 (59%)
 Pain (narcotic) 14 (27%) 9 (21%) −0.286 0.591
 Pain (non-narcotic) 19 (37%) 16 (36%) 0.134 0.781
 Pain (over the counter) 9 (17%) 9 (21%) 0.300 0.596
Other 26 (50%) 23 (52%)
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Note: B, unstandardized regression coefficient (reference category: waitlist) controlling for age, sex, relationship status, traumatic brain injury comorbidity, and physical health.

Discussion

The objective of this study was to examine the association between having a PTSD service dog and self-reported medication use among a population of military veterans with PTSD with and without a service dog. Although veterans with a service dog were more likely than those on the waitlist to report that their doctor had decreased dosage or removed medications since getting their dog, there were no significant differences from the waitlist when they were asked to write out the names of the medications they took. Specifically, after controlling for covariates, there was no effect of having a service dog on whether veterans reported taking physical health, mental health, sleep, or pain medications. The results of this preliminary cross-sectional study should be interpreted with caution, as future within-subject and pharmacy-verified research is necessary to fully understand the potential effect of service dogs on pharmacotherapy among military veterans with PTSD.

Compared to the waitlist, veterans with a service dog were more likely to report that their doctor had decreased a dose or removed a medication from their regimens. In contrast, veterans on the waitlist were more likely to report no changes or an increased dosage to their medication regimen. Qualitative reports have similarly suggested after getting a service dog, veterans report decreases in both the frequency of intake or the dosage of many of their medications (Husband et al., 2020; Krause-Parello & Morales, 2018; Lessard et al., 2018; Yarborough et al., 2018). For example, in a series of ten case studies, five veterans reported that since receiving a service dog they had either decreased or stabilized their intake of medications in the categories of mood stabilizers, sleep quality/inductors, and antidepressant medications (Lessard et al., 2018). Other qualitative reports from veterans suggest that having a PTSD service dog can lead to reduced or discontinued medications for mental and physical health (Yarborough et al., 2018) as well psychotropic medications needed for anxiety and depression (Krause-Parello & Morales, 2018). Future research is warranted to further explore the potential changes in medication dosages and intake over time using longitudinal designs, pharmacy record verification, and larger sample sizes.

There was no significant effect of having a dog on physical health medications including those for blood pressure and migraines. Previous research on human–canine interactions has suggested potential short-term and long-term positive physiological effects of dog interactions. For example, short-term interactions with a friendly dog have been found to decrease blood pressure and stress-related neurohormones (Odendaal & Meintjes, 2003). In addition, some cross-sectional studies have found associations between pet ownership and lower blood pressure (e.g., Anderson et al., 1992). However, other studies have failed to replicate these findings and have argued for the need for longitudinal analyses to truly understand the relationship between pet ownership and cardiovascular health (Parslow & Jorm, 2003). In addition to the lack of baseline data in this pilot study, the long-term physiological effects of PTSD service dogs may be clouded by the variable times of service dog partnership in the sample (ranging from 1 month to 4 years). Null findings regarding migraine medications may also be due to the co-occurring TBIs in this population. Specifically, the migraine and tension-type headaches associated with TBIs may be chronic and not likely to improve with the addition of a service dog (Lahz & Bryant, 1996; Lucas et al., 2014).

Results also found no observed group differences in psychiatric medication use, including antidepressants, antipsychotics, and anxiolytic medications. Previous qualitative reports have suggested a decreased reliance on some psychiatric medications after receiving a PTSD service dog (Husband et al., 2020; Krause-Parello & Morales, 2018; Lessard et al., 2018; Yarborough et al., 2018). Results from this same study population have also suggested a significant effect of having a service dog on PTSD symptoms, anxiety/depression, and psychological wellbeing (O'Haire & Rodriguez, 2018). It is of note that this study did not quantify antidepressant dosage nor consider the frequency of use of as needed anxiolytic medications. It is possible that if these aspects of medication use were considered, results may have identified group differences. However, it is important to note that decreased use of some medications such as antipsychotics or antidepressants may be positive for those who desire to reduce their reliance on medications or have experienced negative side effects, but can also be a hindrance to remission, recovery, or stability if medications are stopped too early or too abruptly (Batelaan et al., 2017). While this pilot study is unable to draw conclusions regarding veterans’ readiness for discontinuing medication, future research can more closely examine this consideration.

There was no association between service dog ownership and pain medication use. Specifically, those with and without a service dog did not differ in their use of narcotics, non-narcotic, or over-the-counter pain medications. While human–animal interaction research has previously found that short interactions with dogs are associated with less perceived pain (Marcus et al., 2013) and that pet dogs may be potentially helpful as an adjunct in managing chronic pain (Bradley & Bennett, 2015), future research is warranted to examine specific instances in which animals may help alleviate subjective pain and consequently influence medication use. For example, it may be that animal interaction can reduce subjective pain severity in some contexts (e.g., post-operative pain), but may not influence the chronic musculoskeletal pain commonly experienced by military veterans (Runnals et al., 2013).

More participants on the waitlist reported taking sleep and nightmare medications than those with a service dog (77% vs 59%). However, the effect of having a service dog on reported medications for sleep or nightmares was not significant (p’s < 0.067). Trauma-related nightmares and sleep disturbances are common symptoms of PTSD, and the medication prazosin is often prescribed to those with PTSD to aid with the prevalence of nightmares (Krystal & Davidson, 2007). Although more veterans on the waitlist reported taking this medication for nightmares compared to veterans with a service dog (37% vs 21%), after controlling for covariates the effect of having a dog on this prevalence did not reach significance. Many PTSD service dogs, including those from our study population, are trained to wake up their owners from a nightmare if the dog observes physical signs of distress (Krause-Parello & Morales, 2018; Yarborough et al., 2018). However, while this behavior may be helpful and comforting to veterans, it may not be eliminating veterans’ reliance on medication to treat the severity of these nightmares. Qualitative interviews also have suggested a service dog may help veterans feel less hypervigilant when falling asleep (e.g., Krause-Parello & Morales, 2018). However, research with this same study population found a significant effect of having a service dog on sleep disturbances, but not overall sleep quality (Rodriguez et al., 2018). Research with pet dog owners has found that people who sleep with their dog in their bed have significantly worse sleep quality than those who do not (Patel et al., 2017). Further research using an objective form of sleep assessment will be helpful to determine the specific aspects and potential mechanisms in which a service dog may affect sleep, as well as the potential individual differences in bed arrangement and sleep habits that may affect these outcomes.

There were notable limitations within this study. First, of the 33 participants (26% of sample) that did not list any medications, it was not possible to determine if these veterans did not currently take medications or if these veterans did not want to report their medications (or felt may have been too burdensome to report). Second, among those who did report medications, we chose to dually code medications that were taken for more than one use (e.g., migraines and sleep) which may have introduced non-independence in the data. Additionally, this data relied on self-report rather than verification from a pharmacy which may have introduced bias by veterans inaccurately reporting their medications. However, in comparing reported medication use from this population to other veteran populations, it seems that medication reporting was not under- or over-exaggerated. The high prevalence of antidepressant medication use in this population (84% of veterans with a service dog and 87% of those on the waitlist) is in line with similar surveys of military veterans with PTSD; in a 2008 study, 85% of military veterans diagnosed with PTSD at a VA hospital (n = 274,297) were found to be prescribed SSRIs (Mohamed & Rosenheck, 2008). SSRIs including Sertraline and Paroxetine are also recommended as first-line treatment options for PTSD (US Department of Veterans Affairs/US Departent of Defense Management of Post-Traumatic Stress Disorders Working Group, 2017). Psychiatric and pain medication use also roughly aligns with data from Woodward and colleagues (2017); of n = 23 veterans with chronic military-related PTSD that had a PTSD service dog, 74% reported taking SSRIs (vs. current sample 85%), 17% antipsychotics (vs. current sample 22%), 17% opioids/narcotics (vs. current sample 24%). However, future research with larger sample sizes and pharmacy verification is needed to be able to compare the medication use of those with a PTSD service dog to the general population of military veterans receiving PTSD treatment.

A notable limitation of this cross-sectional research is that we cannot account for baseline medication use before obtaining a service dog. This pilot study was cross-sectional such that only preliminary causational conclusions can be drawn. Future longitudinal research will be beneficial to follow participants’ medication regimens, adjustments, and changes to dosage over the course of obtaining a service dog or remaining on the waitlist. Additionally, although we quantified whether and how frequently participants were engaging in PTSD treatment other than having a service dog, the types of PTSD treatment (e.g., evidence-based or complementary) that veterans were engaging in were not quantified. Thus, we are unable to determine or control for the potential effects of other treatments on medication outcomes besides having a service dog. Finally, the sample contained only United States post-9/11 veterans recruited from a single service dog provider; it is unknown how these results may generalize to other veteran populations and/or service dog providers.

In conclusion, this preliminary, cross-sectional data suggests that although veterans report that their doctor has made reductions in the number and dosage of their medications since receiving a service dog, an analysis of their self-reported list of medications indicates no significant differences in medication numbers or types between those with a service dog and those on the waitlist to receive one. These findings provide a foundation to continue investigating the effects of PTSD service dogs and canine-assisted interventions on pharmacotherapy of veterans with PTSD. Longitudinal, randomized designs with pharmacy verification are necessary to determine the effect of service dogs on medication use within-participants while accounting for baseline medication use. As this practice continues to increase in popularity, future research is warranted to understand how the addition of a PTSD service dog integrates into both PTSD treatment and medication regimens in this population.

Acknowledgements

We also acknowledge the participation of our collaborators at K9s For Warriors for their assistance in completing this research.

Funding

This study was funded by the Human–Animal Bond Research Institute (HABRI; Grant D15HA-031) and Bayer Animal Health. Its publication was made possible with support from Grants KL2TR001106 and UL1TR001108 (A. Shekhar, PI) from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award.

Footnotes

Disclosure Statement

The authors declare no conflicts of interest.

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