Military families—a service member or veteran of the armed forces and their immediate family members—may be at risk for a multitude of concerns both inter- and intra-personally. The training and subsequent military service of the service member or veteran (hereafter, veteran) may each lead to significant emotional and mental health changes and challenges for both the veteran and their families (1, 2). As a result, family-focused interventions may be particularly effective in promoting mental and physical wellbeing and resilience in the context of military families (3). One category of complementary intervention that shows promise for military families is animal-assisted interventions (AAIs).

AAIs are defined as “any intervention that intentionally includes or incorporates animals as part of a therapeutic or ameliorative process” (4, p. 25). According to prior research, the human-animal bond that may develop during AAIs shares similarities with attachment bonds, potentially contributing to the effectiveness of these interventions (5, 6). This bond may serve as a crucial component of the therapeutic process (7). While a wide variety of literature has explored the impact of AAI for veterans [see recent reviews; (8–10)], much of the literature that has included measures of family-wide impacts has done so solely from the perspective of the veteran. The veteran’s experience may or may not align with the experiences of other family members; therefore, there is a need for studies that are designed and powered to collect data directly from military family members other than (or in addition to) the veterans themselves.

We conducted a systematic literature review in accordance with PRISMA guidelines. A total of five databases were searched from their inception date to 1 March 2023 (ERIC, ProQuest Research Library, ProQuest Dissertations and Theses, PsycINFO, PubMed, and Scopus). In addition, the Human-Animal Bond Research Institute (HABRI) Central Database and the Journal of Veteran Studies were hand-searched for relevant articles. Search terms included a term for military families and a term for animal-assisted or pet. The terms for military families included: military and/or veteran families/spouses/partners/children/couples. The terms for animal-assisted/pet were adapted from a previous AAI literature review (34), and included: animal intervention, animal therapy, animal assisted, animal facilitated, anthrozoology, assistance animal(s), assistance dog(s), assistance horse(s), canine therapy, canine assisted, canine facilitated, companion animal(s), dog therapy, dog assisted, dog facilitated, dolphin therapy, dolphin assisted, dolphin facilitated, equine therapy, equine assisted, equine facilitated, hippotherapy, horseback riding, human animal bond, human animal interaction(s), pet therapy, pet assisted, pet facilitated, service animal(s), service dog(s), service horse(s), therapeutic animal(s), therapeutic dog(s), therapeutic horse(s), therapeutic horseback, therapeutic pet(s), therapeutic riding, and therapy with animals. Specific search formatting was adapted according to the syntax rules for each database. While this review was not pre-registered, the protocol was developed in advance, prior to conducting the database search.

Inclusion criteria for articles included:

Publication in English in a peer-reviewed journal or as a dissertation

Exclusion criteria included:

Not published in English

Both authors conducted an initial screening for inclusion based on titles and abstracts. Selected articles were then read in full by both authors to make a final determination (Cohen’s Kappa = 1.0). Disagreements were resolved through discussion. Article screening flow is presented in Figure 1. Both authors independently coded 20% of the articles to establish adequate inter-rater reliability. Finally, the first author (LN) coded 100% of the articles.

Methodological rigor was assessed adapting binary (yes/no) scoring questions from a previous human-animal interaction review (see Supplementary Material) (9). Questions focused on transparency of study methods (e.g., Was the aim of the study stated? Was there a clear description of participant eligibility? Was ethical approval attained?); the study design (quantitative, qualitative, or mixed methods) dictated the applicable methodology-specific questions.

To date, nine articles have been published that specifically collected data focused on AAIs directly from military family members (Table 1). Four articles (44%) focused on the influence of equine-assisted services (EAS) for military families and five (56%) focused on the influence of service dogs on military families. Three of the five articles focused on service dogs were from the same clinical trial, each reporting on a different data stream of the parent trial. None of the articles that met our eligibility criteria for inclusion included AAIs with animals other than horses or dogs. One of the articles (11%) was an unpublished dissertation. Eight of the nine articles (89%) reported findings from studies that were completed in the United States, and one that was completed in Germany (11%). The articles were published in a range of interdisciplinary journals. The earliest article was published in 2018 and the most recent in 2022 with seven of the nine articles (78%) published within 3 years prior to the search being conducted.

The overarching research question guiding this review was, “What are the effects of AAIs on wellbeing of military family members?” A total of nine articles met the criteria to be included. Overall, findings support the notion that AAIs may be well-suited as a complementary family-focused intervention for military families, but more research is needed.

Thus far, limited research focused on AAI for military families has examined two types of AAI: service dog placements and equine-assisted services. Across articles, the equine-assisted services varied widely from observation to groundwork to mounted riding, whereas the characteristics of the service dog placements were relatively homogeneous. This is unsurprising given that four out of the five service dog studies included dogs trained and placed by the same service dog provider. A fruitful direction for future research will be to explore other types of AAIs (beyond equine-assisted interventions and service dog partnerships) and to incorporate multiple providers.

AAIs have the potential to help not only families with ongoing mental or physical health concerns, but also families with other types of challenges such as general family functioning, stress reduction, and post-deployment readjustment. Though not studied in the context of military families, there is preliminary data on other types of AAIs that may be effective for addressing concerns relevant to military families. For example, studies suggest that participation in care farms may provide benefits to mental health (44, 45) and that therapy dog visits or the presence of facility dogs may have positive effects on wellbeing (46, 47). Though these AAIs have solely been studied for individual participants, it seems plausible that similar impacts could be found for families. Additionally, though not a goal-oriented AAI, the role of companion animals in military families should be a continued focus. Given the perception of companion animals as family members, they may have an important role in family functioning and communication for military families.

A major gap evident in the current body of literature is the lack of knowledge surrounding the bi-directional influence of one family member’s outcome on another family member’s outcome. Future studies should, for example, consider associations between family member outcomes and plan for analyses capable of identifying key predictors at both the individual and the dyad level. Similar methodology has, for example, been incorporated into a study of children with service dogs for autism and their families, providing a possible template for exploring the quantitative influence of human-animal interactions within family systems [e.g., (48)]. Additionally, instead of being an add-on to studies focused primarily on veterans, it is important for studies to be designed and powered to specifically study family-focused interventions, considering the military family as a whole unit.

Key concepts found in the current literature regarding AAIs for military families are aligned with the broader literature on military family-focused interventions. In both the literature on military family-focused interventions more broadly and the literature on AAIs for military families, interventions primarily take place in the context of a veteran receiving a diagnosis of PTSD, or when intimate partner violence has occurred (49). Family involvement in treatment for PTSD has been shown to potentially reduce dropout rates, which are a major concern for treatment success (50). Multiple evidence-based family-focused intervention frameworks exist for the treatment of PTSD (51). Future studies should consider combining these already evidence-based approaches with AAI, for example combining a therapy dog visit with cognitive behavioral conjoint therapy, to explore the potential cumulative effects of the interventions.

Only one study reported findings related to the experience of military children. This mirrors the general military family intervention literature, which also has limited studies on the experience of children in comparison to other family members (21). Given that children in military families can experience unique challenges and concerns, this is an important area for future exploration.

Overall, the quality of the methodology for studies in this review was average and there is room for improvement. The number of articles was limited, and there was significant variation in the measures used to measure outcomes. When studies do not consistently employ the same outcome measures, it prevents conducting a meta-analysis, which is important to establish an evidence base for any intervention or complementary intervention. Furthermore, there are currently no randomized clinical trials comparing outcomes for AAIs to other types of family-focused interventions. Without randomization, no causal claims can be made about the impacts of AAIs for military families.

Despite these gaps, preliminary evidence suggests that AAIs may be effective for military families. Outcomes from the current review were primarily positive, and challenges highlight opportunities to refine or improve the interventions themselves. Though this review was focused on studies that reported outcomes of military family members (other than or in addition to veterans), findings are also relevant to practitioners of interventions aimed at individual family members. For example, although a service dog intervention is typically targeted toward a single family member (the veteran with a disability), studies suggest that the service dog intervention may have an influence that extends to the whole family (39, 41). This is unsurprising given that family systems are complex and what happens to one family member (positive or negative) ripples through the rest of the family (52). The “ripple effect” of service dog partnerships throughout the whole family system is notable and important for providers to consider, and further underscores the possibility that family-focused interventions might be particularly suitable to military families.

Within the military family literature there is a call to include all members of the military family in both the interventions and the research, beyond solely the veterans (12, 21, 53). AAIs are a promising potential answer to this call because they can be highly individualized and may impact the entire family. In the case of equine-assisted services, the whole family can participate together. In the case of service dog placements, the dogs often interact with all family members even though they are specifically trained for the veterans.

Military families need support to promote resilience and diminish concerns with mental or social health following military-related challenges. The mental and social health concerns that they may experience have the potential to be addressed through AAIs focused on and developed for the entire military family unit, rather than solely for individual members. Despite this significant potential, very few articles in the literature to date have focused on AAIs for military families as the primary population. Despite the limited quantity of studies, preliminary data suggests that in conjunction with other services, animal-assisted interventions may have the potential to promote resilience and wellbeing in military families.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

LN: Conceptualization, Data curation, Funding acquisition, Formal analysis, Investigation, Methodology, Project administration, Supervision, Writing – original draft, Writing – review & editing. SL: Data curation, Formal analysis, Investigation, Methodology, Writing – original draft, Writing – review & editing, Funding acquisition.