Relation of post-traumatic stress disorder symptom severity to the efficacy of an animal-assisted intervention for stress reduction after military aeromedical evacuation

Animal-assisted interventions (AAIs) have been found to decrease stress in some settings, but it is not known if AAI is feasible in an aeromedical staging facility or effective in reducing stress following aeromedical evacuation (AE) of military personnel. An experimental design was used to evaluate the efficacy of AAI at reducing stress in AE military patients (N = 120). Patients participated in a 20-min AAI (n = 60) or 20-min informational session about assistance dogs as an attention-control group (n = 60). Demographics, post-traumatic stress symptom severity (PTSSS), and stress biomarkers (cortisol, alpha-amylase, and immunoglobulin A) were collected regular intervals. AAI was found feasible and efficacious at reducing stress. Cortisol decreased significantly (p < .05) in the AAI group compared with the attention-control group. PTSSS moderated the immunoglobulin A responses to AAI as demonstrated by the interaction of PTSD Checklist-Military Version score, group, and time, F(1, 111.23) = 4.15 p = .044; effect size: d = 0.31. This research supports AAI as a stress-reducing modality in AE patients, particularly those who report higher PTSSS. Implications for future research are discussed.