Can Dogs Predict PTSD Flashbacks?

Post-traumatic stress disorder (PTSD) is a debilitating mental health condition that affects millions of people worldwide. With its high prevalence among both military and civilian populations, finding effective treatments and interventions is crucial. One innovative approach that has gained attention in recent years is the use of PTSD assistance dogs. These specially trained canines provide support and assistance to individuals struggling with PTSD symptoms. However, the scientific validation of their effectiveness is still ongoing. A groundbreaking study conducted by researchers at Dalhousie University has shed new light on the potential of scent-detection dogs to identify stress-related volatile organic compounds (VOCs) in the breath of individuals with trauma histories. This research could have significant implications for improving the training and effectiveness of PTSD assistance  dogs, particularly in enhancing their ability to alert their handlers to impending symptoms.

1712332175775.jpg

The Study: A Proof-of-Concept Approach

The study, led by researchers from the Canine Olfaction Lab and the Mood, Anxiety, and Addictions Comorbidity Lab at Dalhousie University, aimed to investigate whether dogs could detect stress-related VOCs in the breath of people with trauma histories when exposed to personalized trauma cues.

Methodology

The researchers collected breath samples from 26 human participants over 40 experimental sessions. These samples were taken during two distinct states:

  1. A calm state (control breath sample)
  2. A stressed state induced by exposure to personalised trauma cues (target breath sample)

Two scent detection canines were then presented with these samples in two different tasks:

  1. A two-alternative forced choice (2AFC) discrimination task
  2. A yes/no detection task

The 2AFC task assessed the dogs' ability to discriminate between the two states within the breath samples of a single individual. The detection task, on the other hand, evaluated their ability to generalise the target odor across different individuals and different stressful events of one individual.

Callie_study.jpg

Results

The results of the study were remarkable:

  • In the discrimination experiment, the dogs performed with approximately 90% accuracy across all sample sets.
  • In the detection experiment, the dogs achieved 74% and 81% accuracy, respectively.

 

These findings suggest that some dogs can indeed detect putative VOCs emitted by people with trauma histories when they experience distress associated with PTSD symptoms, including flashbacks.

ivy_researcher.jpg

Intriguing Correlations

One of the most fascinating aspects of the study was the correlation between the dogs' olfactory performance and the human donors' self-reported emotional responses to trauma cue exposure, which may include PTSD flashbacks. This analysis revealed that the dogs might have been detecting distinct endocrine stress markers:

  • One dog's performance correlated with the human donors' self-reported fear responses.
  • The other dog's performance correlated with the human donors' self-reported shame responses, indicating that these dogs performed at very high levels in detecting emotional distress..

 

Based on these correlations, the researchers speculate that the VOCs each dog was detecting likely originated from different stress response systems:

  1. The sympathetico-adreno-medullary (SAM) axis, which produces adrenaline and noradrenaline
  2. The hypothalamo-pituitary-adrenal (HPA) axis, which produces glucocorticoids

This distinction is particularly interesting as it suggests that different dogs might be sensitive to different aspects of the human stress response.

Implications for PTSD Assistance Dogs

The findings of this study have significant implications for the training and deployment of PTSD assistance dogs. Currently, these dogs are typically trained to respond to physical signs of impending intrusion or hyperarousal symptoms, such as fidgeting or fist-clenching. However, if dogs can be trained to rely on olfactory cues, they might be able to alert their handlers to upcoming symptoms before any physical signs manifest. This early detection could provide several benefits:

  1. Earlier intervention: Handlers could be reminded to use coping skills learned in psychotherapy, such as mindfulness or relaxation techniques, before symptoms escalate.
  2. Increased efficacy: Early distraction could enhance the effectiveness of these coping strategies.
  3. Prevention: By alerting handlers before they're consciously aware of their stress, dogs could help prevent full-blown symptom episodes.

The Science Behind Canine Olfaction

To understand the significance of this study, it's essential to appreciate the remarkable olfactory capabilities of dogs. Canines have a sense of smell that is 10,000 to 100,000 times more sensitive than that of humans. This extraordinary ability has led researchers to explore various applications of canine olfaction in medicine, including:

  • Detecting human cancers
  • Identifying viruses like COVID-19
  • Alerting to conditions such as hypoglycemia and seizures
  • Detecting dangerous bacteria

 

Dogs can detect volatile organic compounds (VOCs) that emanate from the human body. These VOCs can be influenced by various factors, including genetics, age, sex, diet, environmental factors, and pathological status. In the case of stress detection, previous studies have shown that dogs can distinguish between human sweat samples collected during stressful and non-stressful situations.

The Endocrinology of Stress and PTSD

Understanding the endocrinological factors associated with PTSD and stress responses is crucial for interpreting the results of this study. PTSD and anxiety disorders are characterised by chronic over-activity of the amygdala and stress response systems. Two main endocrine subsystems play a role in the stress response:

  1. The sympathetic-adreno-medullar (SAM) axis: This system reacts almost instantly to stressors, producing adrenaline and noradrenaline.
  2. The hypothalamic-pituitary-adrenal (HPA) axis: This system responds more slowly, releasing glucocorticoids like cortisol.

The different response times and functions of these systems may explain why the two dogs in the study appeared to be detecting different aspects of the stress response.

Conclusion and Future Directions

This proof-of-concept study is the first to demonstrate that some dogs can detect putative VOCs emitted by people with trauma histories when they experience distress associated with PTSD symptoms. The results open up exciting possibilities for improving the effectiveness and training protocols of PTSD assistance dogs, particularly in enhancing their alert function.

As research in this area continues, we may see the development of more sophisticated training methods for PTSD assistance  dogs, allowing them to provide even more targeted and timely support to individuals struggling with PTSD. This innovative approach could complement existing treatments and interventions, offering new hope to those affected by trauma-related disorders. The intersection of canine olfaction and mental health treatment is a fascinating area of study that holds great promise. As we continue to explore the remarkable abilities of our canine companions, we may discover even more ways in which they can support and improve human health and well-being.