Dogs Sniff Out Human Traumatic Memories, Scientists Say

Recent research has unveiled that dogs might have the ability to detect the onset of flashbacks caused by post-traumatic stress disorder (PTSD) by smelling changes in a person’s breath. This discovery, published in the journal Frontiers in Allergy, stems from training dogs to recognize the specific scents associated with traumatic memories in humans, potentially enhancing the capabilities of PTSD assistance dogs.

PTSD is a condition that can develop after exposure to a traumatic event, leading sufferers to experience severe flashbacks and nightmares. Laura Kiiroja, a researcher at Dalhousie University’s Department of Psychology and Neuroscience in Canada, explained to The Independent that while PTSD service dogs are trained to respond to visible signs of distress, this study suggests dogs can also detect episodes through the scent of a person’s breath.

The basis of this detection lies in the “scent profile” of humans, composed of volatile organic compounds (VOCs) emitted through various secretions like sweat. These profiles may include VOCs related to stress, which dogs could potentially identify.

In the study, 26 participants, more than half diagnosed with PTSD, were asked to breathe into a facemask while recalling traumatic events. The research team trained 25 dogs for scent detection, but only two, Ivy and Callie, consistently showed both skill and enthusiasm for the tasks.

Kiiroja highlighted the dogs’ inherent motivation and their strong desire for rewards, noting that the challenge was often encouraging them to rest rather than work, especially Callie, who was particularly eager.

The dogs were trained to distinguish between the odors collected on the facemasks of stressed and non-stressed individuals. In tests to assess their ability to accurately detect stress-related VOCs, Ivy achieved a 74% accuracy rate, while Callie excelled with an 81% success rate. Interestingly, Ivy’s detection was linked to anxiety, and Callie’s to shame, with both dogs displaying high accuracy but seeming to target slightly different stress signals.

This research opens up the possibility of using dogs’ keen sense of smell to provide better support for individuals with PTSD, highlighting their potential to respond not just to physical and behavioral cues but to chemical signals of stress as well.