A groundbreaking study by Laura Kiiroja and colleagues, published in Frontiers in Allergy, provides first-time evidence that scent-detection dogs can identify stress-associated breath scents from people with trauma histories. The research centers on whether dogs can detect volatile organic compounds (VOCs) linked to emotional distress during PTSD symptom episodes.
The experiment involved 26 participants, over half of whom had a clinical PTSD diagnosis. Each participant provided breath samples during a calm control state and during exposure to a personalized trauma cue designed to provoke distress. These breath samples were then analyzed by two trained scent-detection dogs using a two-alternative forced choice (2AFC) discrimination and a yes/no detection task.
In the discrimination task, dogs had to identify which of two breath samples came from the trauma-cued state. In the detection task, they determined whether a given breath sample reflected stress, generalizing across multiple individuals and traumatic scenarios. The dogs achieved about 90% accuracy in discrimination and 74–81% in detection.
Interestingly, the performance of the two dogs correlated with different emotional responses reported by participants: one dog’s detection accuracy aligned with self-reported fear, while the other aligned with shame. These findings suggest that the dogs were responding to distinct physiological markers—one potentially linked to the sympathetico-adreno-medullary (SAM) axis, responsible for adrenaline release, and the other to the hypothalamo-pituitary-adrenal (HPA) axis, which governs glucocorticoid secretion.
This study lays the foundation for future enhancements in PTSD service dog training. By recognizing that dogs may respond to specific biological markers of distress, handlers and trainers can better tailor alert functions and support mechanisms. The findings also strengthen the role of dogs as potential biosensors for psychological states, particularly in therapeutic and service contexts.
Source: Laura Kiiroja, Stewart S. H., Gadbois S. “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, 2024-03-28. https://doi.org/10.3389/falgy.2024.1340161
