Service dogs may help reduce levels of the stress hormone cortisol in military veterans who have post-traumatic stress disorder (PTSD), a new study finds.
For the study, researchers compared a group of veterans with PTSD who had a service dog to a group of veterans on the waitlist to receive one.
“Our previous research suggests that the presence of a service dog reduced clinical PTSD symptoms and improved quality of life,” said study co-leader Maggie O’Haire. She is an assistant professor of human-animal interaction at Purdue University’s College of Veterinary Medicine, in West Lafayette, Ind.
“In this study, we wanted to determine if those beneficial effects also included changes in the physiology of stress,” O’Haire said in a university news release.
The researchers focused on cortisol, a biomarker involved in the stress response system, and one that is detected through saliva.
According to study co-leader Kerri Rodriguez, “military veterans with a service dog in the home produced more cortisol in the mornings than those on the waitlist.”
Rodriguez explained that “this pattern is closer to the cortisol profile expected in healthy adults without PTSD.”
In addition, “having a service dog was also associated with less anger, less anxiety and better sleep,” she noted. Rodriguez is a human-animal interaction graduate student.
The findings are the first of their kind and offer insight into how service dogs may provide mental health benefits to veterans with PTSD, according to the study authors.
The researchers are now conducting a large-scale, long-term U.S. National Institutes of Health clinical trial comparing veterans with service dogs to those without.
The report was published June 12 in the journal Psychoneuroendocrinology.
The U.S. National Institutes of Health has more on PTSD.