Post-traumatic stress disorder (PTSD) is a widespread condition affecting military veterans and civilians alike. Service dogs have emerged as a supportive intervention, yet scientific evidence of their mechanisms remains limited. In a proof-of-concept study, Kiiroja, Stewart, and Gadbois (2024) explored whether dogs can detect volatile organic compounds (VOCs) linked to trauma-related stress in human breath.
The study involved 26 participants, 54% of whom had PTSD. Breath samples were collected under calm conditions and during stress induced by personalized trauma cues. Two scent-detection dogs completed discrimination and detection tasks. Results showed ~90% accuracy in distinguishing calm vs. stressed breath samples and between 74–81% accuracy in detecting stress VOCs across individuals and events.
Interestingly, each dog’s performance correlated with distinct emotional responses. One dog’s accuracy aligned with fear responses, suggesting detection of stress markers from the sympathetico-adreno-medullary (SAM) axis. The other dog’s accuracy correlated with shame responses, likely reflecting hypothalamo-pituitary-adrenal (HPA) axis activity. These findings suggest that different dogs may specialize in detecting different biochemical stress pathways.
The results highlight the potential of PTSD service dogs to detect early signs of trauma-related distress. By understanding the physiological basis of their scent detection, training protocols could be enhanced to strengthen their alerting functions and improve human mental health outcomes.
Source: Kiiroja, L., Stewart, S. H., & Gadbois, S. (2024). Can scent-detection dogs detect the stress associated with trauma cue exposure in people with trauma histories? A proof-of-concept study. Frontiers in Allergy, 5. Published March 28, 2024.
