What is Separation Anxiety Disorder in Dogs?
Separation anxiety disorder is a disease involving psychological, emotional, behavioral, and physiological aspects. This disorder has been reported in birds, dogs, cat, horse, pig, sheep, goat, cattle, cetaceans (whale, dolphin, or porpoise), and human and nonhuman primates. This discussion will be focused on the canine companion population.
Canine separation anxiety disorder occurs when a given dog is forced to remain at a physical distance from their owner. Dogs affected by separation anxiety disorder can exhibit psychogenic grooming (“over-grooming”) and secondary self-inflicted injury. This disease may be similar to phobic disorders and panic attacks in people. Dogs may show over-exaggeration and overreact to ambiguous or unpredictable situations. Similar to bipolar disorders in people, dogs can fluctuate between manic or agitated states and depressive or subdued states. These clinical signs may be more overt in more severe cases.
How Common is Separation Anxiety in Dogs?
Approximately 14% to 20% of canine patients from general veterinary practices show signs of separation anxiety disorder in their owners’ absence.
However, as with other anxiety disorders in veterinary patients, underdiagnosis of anxiety-dependent separation problems has been previously reported due to misinterpretation of normal and pathological anxiety and the lack of recognition of mild clinical signs by pet owners.
As such, it is suspected that up to 50% to 56% of the overall canine population may actually display clinical signs of anxiety at some point in their life.
To quantify it: out of the total population of approximately 160 million dogs in the United States and Europe, this disease may affect approximately 85 million dogs. Also, separation-related problems are one of the primary cited reasons for the relinquishment of dogs to animal shelters.
Physiological Changes from Separation Anxiety Disorder in Dogs
The more psychological aspects of this disorder are obvious, but also prone to interpretation and subjectivity. The definition of this disorder from within the lens of physiological changes has proven interesting from both an understanding of the disease as well as in aiding veterinarians to diagnose the disease with increased clarity.
There are numerous physiological changes that have been reported in studies of dogs and other animals to be associated with various psychosocial stresses. These include: increased glucocorticoids, increased adrenocorticotropic hormone (ACTH), altered cardiovascular parameters, altered immune parameters, and increased nerve growth factor. Additionally, the neuropeptide oxytocin has been found to attenuate anxiety, central fear responses, and neuroendocrine reactivity. Conversely, the neuropeptide vasopressin has been associated with augmented anxiety and fear expression and increased neuroendocrine stress response.
These two neuropeptides are not only a focus of research because of their direct involvement with affecting behavior as it relates to the stress-response and their seemingly polar opposite effects on the body, but also because they are synthesized in the brain. Oxytocin and vasopressin are synthesized in the hypothalamus, primarily in large magnocellular neurons situated in the supraoptic and paraventricular nuclei, and secreted from their axons, which are projected to the neurohypophysis, into the general circulation.
Diagnosing Separation Anxiety Disorder in Dogs
Physiological biomarkers can be measured from any numbers of bodily fluids and are helpful objective measures of a specific disease. Because the diagnosis of behavior disorders carry a large element of subjectiveness, such behavior biomarkers would be incredibly valuable.
In a 2019 veterinary research study, dogs with separation anxiety have been shown to depict exploratory behavior at a rate that is significantly less than normal dogs. Additionally, those dogs with anxiety were significantly more persistent in expressing passive stress-coping strategies aimed at seeking proximity to their pet owners. Upon reuniting with their owners, those dogs with separation distress spent significantly more time jumping up on the strangers than normal dogs did.
The researchers in this study also found that the concentrations of oxytocin and vasopressin hormones collected from the salivary glands of anxious dogs did not differ between samples taken before the separation. However, vasopressin concentrations immediately after separation were significantly higher. These results indicated that dogs with separation distress became more anxious than normal dogs when separated from their owner in an unfamiliar environment and provided preliminary support for the use of salivary vasopressin as a possible biomarker for anxiety-related responses in dogs.
