In response to the critical need for adjunctive treatments for soldiers with refractory forms of mental injury — primarily posttraumatic stress disorder (PTSD) — the US military is developing complementary and alternative medicine (CAM) techniques, including animal-assisted intervention (AAI).1,2
CAM modalities include therapies such as yoga, meditation, and creative art therapies, shown to have an effect on the mind’s capacity to regulate the brain and body’s response to social and environmental challenges by reducing stress and enhancing the immune function through the release of the neuropeptide oxytocin by the brain.
Olff et al3 suggest PTSD symptom treatment would be improved by increasing endogenous levels of oxytocin through optimizing of social support. Studies show that dogs can provide such an optimization of social support and that positive interactions with dogs may offer a safe, effective, and relatively inexpensive way to increase endogenous levels of oxytocin and other important anti-stress agents in humans.
Valerie, a golden retriever, demonstrates her ability to connect with a sailor at the National Intrepid Center of Excellence. Image courtesy of Rick Yount, MS, LSW.
Oxytocin is a well-established modulator of a pro-social, anti-stress brain network with the potential to modulate symptoms of PTSD such as: anxiety, including fear response and hyperarousal; interpersonal difficulties/social isolation; physical pain; and sleep disturbances. Human oxytocin research has shown that oxytocin can increase our sense of trust, empathy, and optimism and even increase our response to hypnosis. In rodents, central administration of oxytocin enhanced acupuncture’s analgesic effects. Studies also suggest that oxytocin is a central mediator of the placebo effect.4–7
Several studies show that friendly, social interaction with dogs increases blood and urine levels of oxytocin in humans.8–12 These human-dog, contact-induced effects gain particular significance in light of a recent brain imaging study which showed that peripheral increases in oxytocin correspond with concurrent activation of the oxytocin brain centers that control the human stress response.13
Oxytocin neurons originate in the hypothalamus and connect to the major brain centers that control behavior and emotion. Oxytocin modulates the hypothalmic-pituitary-adrenal axis (HPA axis), the locus coeruleus, the central amygdala (CeA) and other arousal centers of the central nervous system to attenuate stress-induced neuroendocrine activity. Oxytocin receptor-expressing neural circuits in the CeA connect to the medial prefrontal cortex to suppress neurons that produce the freezing reaction to fear, while promoting risk assessment and exploratory response to frightening stimulus.
Oxytocin has also been shown to modulate the serotonin system and reduce levels of cytokines, adrenocorticotropic hormone, and cortisol. All of these brain systems and neurochemical responses have shown to be functionally important in PTSD.14–21
With respect to pain and sleep disturbances, oxytocin has been shown to modulate pain in humans and has been shown to impact sleep patterns in animal studies.22–24 Oxytocin has also been shown to be a powerful antioxidant that can bolster the immune system and protect against sepsis.25,26
One dose of oxytocin given to war veterans with PTSD demonstrated decreased physiologic responding to provoked combat memories.27 Oxytocin in humans, has been shown to enhance the processing of positive social information compared to negative information, increase a sense of trust in others, reverse the effect of aversive conditioning of social stimuli, enhance the buffering effect of social support on stress responsiveness, and reduce the stress response in people with a history of early trauma.28
This same pro-social/anti-stress response has also been observed in service members with PTSD who train service dogs. As we will demonstrate, shaping the behaviors of service dogs requires the focused nurturing social attention towards dogs that has been shown to naturally increase oxytocin blood levels in humans.
There are many potential…