Tag Archives: cortisol

Veterans with PTSD receive physiological and behavioral benefits thanks to service dogs

A new study shows how veterans with PTSD may benefit physiologically from using service dogs.

This study, led by the Purdue University College of Veterinary Medicine, is the first published research to use a physiological marker to define the biobehavioral effects of service dogs on veterans with PTSD.

The findings were published in the journal Psychoneuroendocrinology, and they may be significant as scientific evidence of potential mental health benefits experienced by veterans with PTSD who have service dogs.

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Kerri Rodriguez, human-animal interaction graduate student (left), and Maggie O’Haire, assistant professor of human-animal interaction in the College of Veterinary Medicine, look at cortisol samples. Cortisol was one of the measurements used in a new study that shows how veterans with PTSD may benefit physiologically from using service dogs. (Purdue University photo/ Kevin Doerr)

The study was co-funded by the Human Animal Bond Research Institute (HABRI) and Bayer Animal Health.  The research was led by Maggie O’Haire, assistant professor of human-animal interaction in the College of Veterinary Medicine, and Kerri Rodriguez, human-animal interaction graduate student, with the help of K9s For Warriors, an accredited nonprofit organization that provides veterans with service dogs. The study also was in collaboration with the Institute for Interdisciplinary Salivary Bioscience Research at the University of California, Irvine.

“Our long-term research goal is to quantify how service dogs may affect the health and well-being of military members and veterans with PTSD,” O’Haire said. “This study compared a group of veterans with PTSD who had a service dog to a group on the waitlist to receive one. Our previous research suggests that the presence of a service dog reduced clinical PTSD symptoms and improved quality of life. In this study, we wanted to determine if those beneficial effects also included changes in the physiology of stress.”

“We chose to focus our assessments on cortisol as it is a biomarker centrally involved in the stress response system,” said Rodriguez, lead author on the paper. In this way, the study seeks to improve the understanding of the potential mechanisms for how and why a service dog may help this population.

Cortisol can be measured non-invasively in saliva, which enabled the veterans to collect samples themselves at home immediately after waking up in the morning and about 30 minutes later. This allowed researchers to look at how much cortisol was being produced during the morning. The magnitude of the “cortisol awakening response” has been extensively studied and is used as a metric of the effects of chronic and acute stress. Non-PTSD, healthy adults experience an increase in cortisol after waking up.

“We found that military veterans with a service dog in the home produced more cortisol in the mornings than those on the waitlist,” Rodriguez said. “This pattern is closer to the cortisol profile expected in healthy adults without PTSD. Having a service dog was also associated with less anger, less anxiety, and better sleep.”

O’Haire says, though, while this finding is important, it should be taken in context.

“These findings present exciting initial data regarding the physiological response to living with a service dog. However, the study did not establish a direct correlation, on an individual level, between cortisol levels and levels of PTSD symptoms, and further study is needed. It is important to keep in mind that service dogs do not appear to be a cure for PTSD,” O’Haire said.

The next step, already underway, involves a large-scale National Institutes of Health clinical trial in which the researchers are studying veterans with and without service dogs over an extended period of time.

“Our research team will be able to look at morning cortisol levels both before and after getting a service dog to see how these physiological effects manifest over time,” O’Haire said. “The longitudinal nature of this clinical trial should bring about a better understanding of the interrelationships between physiological and behavioral processes, PTSD symptoms, and service dogs.”

She also emphasizes that the participation of veterans in the studies should not be taken for granted. “We are most grateful to the military veterans and their families who have participated in the research thus far,” O’Haire said. “We are honored to be collaborating with these individuals to advance the science behind our interactions with animals and how they affect human lives.”

Source:  Purdue University media release

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Using dog hair for diagnosis

Dog hair is used to diagnose hyperadrenocorticism (Photo: Ouschan/Vetmeduni Vienna)

Dog hair is used to diagnose hyperadrenocorticism (Photo: Ouschan/Vetmeduni Vienna)

Many dogs suffer from hyperadrenocorticism, more commonly known as Cushing’s Disease.   The disease is characterised by excessive amounts of hormones known as glucocorticoids that are produced by the adrenal glands.  The disease is more common in older dogs.  Most cases result from a tumour in the pituitary gland but some are caused by tumours in the adrenal glands.

The symptoms of a dog with Cushing’s Disease often ‘creep up’ on the owner and vet.  Common symptoms include excessive drinking (and urination) and overeating, leading to a pot-bellied appearance, as well as with loss of hair.  Since all of these symptoms can stem from a number of disorders, it is difficult to be certain.  The methods traditionally used to diagnose the disease are complicated and costly and usually give information about the hormone concentrations at the time a sample is taken.  Since most dogs are stressed by veterinary examinations, their hormone levels will peak  because of the stress – making it difficult to rely on the analytical results.

Researcher Claudia Ouschan and colleagues at the University of Veterinary Medicine, Vienna decided to look for a way to monitor the long-term levels of glucocorticoids in dog hair that would also offer a diagnostic option that was less stressful to the dogs.   She compared the levels of cortisol, corticosterone and cortisone in the hair of twelve dogs with hyperadrenocorticism and ten healthy dogs.  The results were striking:  all three hormones were found at far higher levels in the hair of dogs with Cushing’s Disease than in the control group, with the increase in cortisol particularly pronounced.

She concludes, ‘we think it (our findings) have real promise for use as a rapid and non-invasive method to diagnose hyperadrenocorticism.’

Her research has been published in the journal Veterinary Dermatology.

Source:  University of Veterinary Medicine, Vienna media statement

Hug me, I need the oxytocin

Oxytocin is a mammalian hormone that is released during the act of touching and hugging.   For these reasons, the hormone is often referred to as ‘the cuddle hormone’ or ‘the love hormone.’  (The hormone is also released during childbirth, by the way).

As a dog owner, your relationship with your dog is likely to involve you and your dog triggering the release of oxytocin in one another.  Temple Grandin, animal behaviourist and autism researcher, has found that ‘A dog’s oxytocin levels rise when his owners pet him and petting his dog raises the owner’s oxytocin too.’    In other words, this hormone plays a role in the human-animal bond.

In 2003, J.S.J. Odendaal and R.A. Meintjes of the  Life Sciences Institute at Pretoria published research into the blood levels of endorphins, oxytocin, prolactin, B-phenylethylamine and dopamine (all associated with pleasure response or relaxation) and cortisol (a known stress hormone) in people and dogs both before and after they interacted with each other.  The researchers compared levels of the neurochemicals under three scenarios:   1) after people petted their own dogs 2)  after they petted unfamiliar dogs and 3) after they sat quietly and read a book.

In both humans and dogs, the levels of the pleasure-response chemicals  rose after 5 to 24 minutes.  At the same time, cortisol levels in humans fell as they spent time with their pets.   The increase in oxytocin was highest in the group where people interacted with their own dogs, as opposed to dogs that were unfamiliar to them.

In 2008, Miho Nagasawa’s research team in Japan showed that only eye contact was necessary between dogs and their humans to increase oxytocin levels.  After 30 minutes of contact with their dog, owners showed an increase in oxytocin levels.

Dr Kerstin Uvnäs-Moberg from Uppsala University, studies oxytocin and its effects.  Her 2010 study showed that women and their dogs experienced increases in their oxytocin levels after only 10 minutes of contact.  When compared to a survey of the women, their oxytocin response was in direct correlation with the quality of the bond they felt for their pet.

For those of us who have experienced this bond during our lives, it is probably not surprising that there is a scientific reason for our feelings and that it is hormone-related.  But it’s nice to have science on our side.

For those of you raising puppies, these studies show that there  is a good scientific reason to ensure your  puppy is socialised.  It is not surprising  that dogs involved in hoarding cases or puppy mills are withdrawn and in many cases frightened of humans.  They aren’t accustomed to the positive effects of oxytocin release and in many cases have suffered other traumas.

Hey Daisy, give me a hug…I need the oxytocin.

Have you hugged your dog today?

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand