Dogs are known for their highly developed sense of smell, believed to be 10,000 times more powerful than that of humans. This ability has proved invaluable in the detection of a number of diseases, including diabetes, malaria and certain cancers.
And now, a Canadian study suggests it could even help prevent and minimise the effects of post-traumatic stress.
The authors of this research, published in the journal Frontiers in Allergy, came to this conclusion after conducting an experiment with 26 people who suffer from PTSD – psychiatric disorders that occur after a traumatic event.
PTSD manifests through repeated memories of, or even reliving, trauma in the form of upsetting flashbacks and nightmares, as well as physical complications that can profoundly alter the personal, social and professional lives of sufferers as well as those close to them.
For the research, the study participants donned medical-grade face masks before being placed in a state of stress so researchers could collect a sample of their breath.
These samples were then presented to Ivy and Callie, two dogs that had previously been trained to smell stress. Notably, previous research by a team at Queen’s University Belfast had found that canines can detect the chemical changes at work in individuals experiencing stress in their breath and perspiration.
In the new study, Ivy and Callie were able to detect a difference in breath samples from a person suffering from a PTSD flashback episode, with an accuracy rate of 90%.
However, the scientists noted that the dogs did not seem to perceive the same volatile organic compounds (VOCs) in the volunteers’ breath when they were “merely” experiencing a non-PTSD-related stressful episode.
“Our proof-of-concept study is the first to demonstrate that some dogs can detect VOCs emitted by people with trauma histories when experiencing distress theoretically associated with the symptoms of PTSD,” the authors wrote.
They also speculated that Ivy was “attuned to sympathetic-adreno-medullar axis hormones (such as adrenaline), while Callie was oriented to the hypothalamo-pituitary-adrenal axis hormones (like cortisol)”.
Given the small number of participants, though, the experts caution that their research “needs to be validated by studies with larger sample sizes” as well as “samples from a higher number of stressful events”.
Nevertheless, the findings open up new potential perspectives on the role of assistance dogs for individuals suffering from post-traumatic stress disorder. Their ability to detect early signs of a traumatic flashback episode could transform the way this psychiatric disorder is treated and enable sufferers to lead better lives.