The effect of a service dog on salivary cortisol awakening response in a military population with posttraumatic stress disorder (PTSD)



  • After controlling for state and trait covariates, military veterans with PTSD living with a PTSD service dog exhibited a significantly higher CAR/AUCi than those on the waitlist.
  • Participants living with a service dog also exhibited significantly less PTSD severity as well as less anger, anxiety, sleep disturbance, and alcohol abuse symptoms than those on the waitlist.
  • Findings suggest that in combination with usual care, PTSD service dogs may confer both psychological and physiological effects on military veterans with PTSD.
  • Future, within-subject research will be necessary for replication and to determine potential clinical significance of this preliminary finding.



Recent studies suggest a therapeutic effect of psychiatric service dogs for military veterans with posttraumatic stress disorder (PTSD), but are limited by self-report biases. The current study assessed the effect of PTSD service dogs on the salivary cortisol awakening response (CAR) and arousal-related functioning in a population of military veterans with PTSD.

Participants included 73 post-9/11 military veterans with PTSD including 45 with a service dog and 28 on the waitlist to receive one. Saliva samples were collected on two consecutive weekday mornings at awakening and 30 min later to quantify the cortisol awakening response (CAR) and its area under the curve (AUCi) in addition to standardized survey measures of anxiety, anger, sleep quality and disturbance, and alcohol abuse. There was a significant main effect of having a service dog on both the CAR and the AUCi, with individuals with a service dog exhibiting a higher CAR and AUCi compared to those on the waitlist.

Results also revealed that those with a service dog reported significantly lower anxiety, anger, and sleep disturbance as well as less alcohol abuse compared to those on the waitlist, with medium to large effect sizes. Although those with a service dog reported significantly less PTSD symptom severity, CAR was not significantly associated with PTSD symptoms within or across group. In conclusion, results indicate that the placement of a PTSD service dog may have a significant positive influence on both physiological and psychosocial indicators of wellbeing in military veterans with PTSD.

Although clinical significance cannot be confirmed, a higher CAR/AUCi among those with a service dog may indicate better health and wellbeing in this population. Future within-subject, longitudinal research will be necessary to determine potential clinical significance and impact of individual differences.

Kerri E. Rodriguez, Crystal I. Bryce, Douglas A. Granger, Marguerite E. O’Haire | 2018
In: Psychoneuroendocrinology, ISSN 0306-4530 | 98 | December | 202–210
PTSD (DSM-5), Treatment, Veterans