Dogs can smell trauma flashbacks in our breath

When trained, dogs can smell a flashback of post-traumatic stress disorder (PTSD) before it even happens.

In addition to sniffing out illnesses, detecting bombs and helping humans overcome their mobility challenges, dogs also play an important role in helping to calm people suffering from post-traumatic stress disorder (PTSD).

In these specific cases, these four-legged companions respond to physical and behavioral cues that indicate a health event. flashbackproviding comfort by cuddling the person to remind them that they are in a safe environment.

A team of scientists from Dalhousie University in Nova Scotia wanted to go further and see if dogs could help those suffering from PTSD before the flashbacks happen – in the same way that they can intervene when someone is about to have a seizure, for example.

All human beings have a “olfactory profile” of volatile organic compounds (VOCs), molecules emitted by the body in secretions such as sweat, influenced by genetics, age, activities and other variables. There is some evidence that dogs are able to detect VOCs linked to human stress.

In this sense, the researchers recruited 26 participants diagnosed with PTSD who, in addition to donating their perfumes, participated in sessions where they were reminded of their traumatic experiences while wearing different masks.

One mask provided a calm breath sample – which acted as a control – while the other, which was worn while participants recalled their trauma, provided a target breath sample. During the research, volunteers also had to fill out a questionnaire about their stress levels and emotions.

The team then recruited 25 pet dogs to train in scent detection, but only two were qualified to complete the study: Ivy and Callie.

The dogs were trained to recognize the target odor of pieces of the masks, achieving a surprising result: 90% accuracy in differentiating between a stress sample and a control sample.

In a second experiment, the animals were presented with a series of samples to see if they could accurately detect moments of stress. Ivy achieved 74% accuracy and Callie achieved 81%.

“Service dogs with PTSD are already trained to help people during episodes of distress. However, dogs are currently trained to respond to behavioral and physical cues. Our study showed that at least some dogs can also detect these episodes through breathing”, said the first author of the article, Laura Kiiroja, from Dalhousie University, in Canada.

“Although both dogs performed very accurately, they seemed to have a slightly different idea of what they considered a ‘stressed’ breath sample,” said Kiiroja, quoted by New Atlas. “We speculate that Ivy was tuned to the hormones of the sympathetic-adrenal-medullary axis (such as adrenaline) and Callie was oriented to the hormones of the hypothalamic-pituitary-adrenal axis (such as cortisol). It should be noted that the onset of PTSD symptoms requires sensitivity to hormones in the sympathetic-adrenomedullary axis.”

The scientific article with the discoveries was published in March in Frontiers in Allergy.