Health Topics

Behavioural Changes in Your Senior Dog

(This article was originally published in the November/December 2015 Issue of Pets Magazine and is reproduced here with the permission of the publisher.)

By Rebecca Ledger, BSc (Hons), MSc, PhD, FSB

While some dogs age gracefully, others sometimes show behavioural changes that cause their owners considerable concern. The development of aggression, disorientation or a breakdown in housetraining in a senior dog, for example, can lead to some owners deciding to relinquish or euthanize their aged pets. However, these behavioural changes may also be signs of dementia, and therefore warrant a visit to the veterinarian.


Veterinarians frequently rely on dog owners to describe the behavioural changes in their dogs that are causing them concern. So, the better owners are at articulating these behavioural changes, the easier it is for the veterinarian to make a diagnosis. Doggy dementia, or canine cognitive dysfunction, comes in different forms; however, the first clue that something is amiss is that the aging dog behaves differently from how it did when younger.


Dogs suffering from age-related cognitive dysfunction can appear easily confused and disorientated in situations that they should know well. This can manifest as the dog looking blankly at walls or the floor, going to the wrong place to be let out, or getting stuck or lost in places that used to be easy to navigate. Some owners also note that their dogs respond to noises and new objects differently, either by becoming less interested or, conversely, by becoming more reactive and barking more in these situations.

Changes in social interactions

As our dogs age, generally we anticipate that they will sleep more, and hence interact with us less. But, for dogs that are developing cognitive decline, they can appear less interested in us, even when they are awake. Watch for decreased interest in greeting you when you return home, either a marked increase or decrease in being petted, as well as increased irritability (not only toward you but also toward other animals in the home).

Changes in sleep-wake cycles

This is one of the most frustrating behavioural changes for owners, for a senior dog that starts to wake up and pace around at night has consequences for the quality of our good night's sleep, too. To balance out the sleeplessness that the dogs experience at night, they typically also start to sleep much more during the day.

Changes in learning and memory

Some dogs become increasingly forgetful as they age, again with troubling consequences for their owners. Dogs that forget the right place to relieve themselves, or that forget how to let their owners know when they need to go outdoors, often start to have accidents inside the home. And, while it is possible to teach old dogs new tricks, dogs suffering from memory problems can be markedly slower at learning anything new, and forgetful of commands they used to know well.

Changes in activity

We expect our aged dogs to become less active simply because their bodies get stiffer. However, the nature of a senior dog's activity can also change when it is suffering from cognitive decline. Watch for aimless pacing and wandering around your home, plus a deterioration in appetite, grooming, playfulness and interest in new things.

Changes in mood

Anxiety increases in both dogs and people as we age. Look for an increase in how easily your dog startles or becomes afraid, especially in response to anything loud or sudden, how much reassurance they demand from you and how distressed they become when left alone.


If you are concerned that your dog may be showing signs of age-related cognitive dysfunction, it is important to make a note of the severity and onset of the symptoms, and to bring them to the attention of your veterinarian. If your veterinarian rules out any possible medical causes for your dog's behavioural deterioration and concludes that your dog is suffering from age-related cognitive dysfunction, they may recommend a variety of treatment options that can help to slow down its progression.


Antioxidants have been found to not only reduce the onset of age-related cognitive decline symptoms in dogs, but also to slow down its progression. These, plus other beneficial anti-aging products have been formulated into diets that are specifically designed to help the aging canine brain. Ask your veterinarian about Hills B/D (brain diet for senior dogs), which is clinically proven to improve the performance of aging dogs on a range of cognitive tasks. Alternately,many of the active ingredients that have been found to improve the behaviour of aging dogs are available as supplements through your veterinarian.

Behavioural enrichment

Mental stimulation is essential to keeping your dog's cognitive health on track, as well as helping to delay any existing deterioration. This stimulation can come in the form of training, exercise and nose work (such as searching for treats hidden in long grass). Playing with new toys, people and other dogs is also highly beneficial. Consider feeding your dog his meals in a puzzle toy, walking some new routes or taking up training classes again, to give your dog opportunities to engage in a variety of positive learning experiences.


Your veterinarian may recommend that your dog be given a daily medication that can help to alleviate some of the signs of his age-related mental deterioration. Approved drugs include products that specifically target anxiety symptoms, some that help to keep agitated dogs calm and others that directly address some of the neurological deterioration and imbalances that lead to cognitive decline. There is evidence that these products have a prophylactic effect, too.

If you are concerned that your dog may be displaying any of these behavioural symptoms, then seek the help of your veterinarian. Above all, it is important to appreciate that brain aging may be the reason why a senior dog's behaviour has become problematic, and that this is the most effectively addressed using a compassionate and clinical approach.