Sundowners in Dogs: Cognitive Dysfunction Syndrome · The Wildest

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Is Your Senior Dog Sundowning?

If your senior dog seems confused, restless, or irritable after dark, they may have sundowners syndrome. Here’s how to deal.

by Dr. Shea Cox, DVM, CVPP, CHPV
Updated April 11, 2022
Brown dog with golden eyes leaning on fence
Anne / Adobe Stock

Just like humans, our pets’ brains change as they get older. A senior dog might have Cognitive Dysfunction Syndrome — also referred to as “sundowner syndrome,” “old dog senility,” or dementia in dogs — a common syndrome that is categorized as a slow, degenerative and progressive disorder in aging pets.

As a dog succumbs to the process, they may experience changes in their awareness, decreased responsiveness to normal surroundings, and increased signs of anxiety that usually worsen in the night hours. Keep reading to learn everything you need to know about sundowners in dogs — including what you can do to help ease the transition. 

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What Are the Symptoms of Sundowners in Dogs?

Many behavior changes seen in senior dogs like confusion, wandering, getting stuck, barking, and obsessive licking are symptoms of this disorder. That said, the symptoms of sundowner syndrome can be lumped into a few general categories:


With sundowner syndrome, dogs may experience disorientation such as going to the wrong side of the door to be let outside or getting lost in familiar environments.

Anxious Interactions

Dogs with sundowners may experience increased irritability, anxiety, or agitation due to a loss in the ability to communicate properly with other animals.

Alterations in Their Sleep-Wake Cycles

This usually means increased restlessness (especially at night) and/or vocalizations that are seemingly directed at nothing in particular; as the disease progresses, you may notice these signs worsening and begin to see your dog aimlessly wandering the house with compulsive behaviors like barking at the wall for no apparent reason or excessive grooming.

Behavior Changes

You may notice your dog becoming less adept at their normal tasks, such as house training or responding appropriately to previously learned commands; you may also notice that your dog has difficulty recognizing and reacting to familiar family members.

How Does Sundowners in Dogs Progress?

The symptoms of sundowners in dogs generally begin very gradually — so much so that many pet parents fail to recognize the early stages of the disease, attributing their dogs subtle behavior changes to “simply getting older.”

A study at the University of California School of Veterinary Medicine demonstrated just how common sundowners syndrome is: Out of 69 dogs, 32% of the 11-year old dogs were affected by sundowner syndrome and 100% of the dogs 16 years of age older were affected.

The exact reason for sundowners in dogs is unknown, but it is thought that the body’s normal degenerative and age-related changes contribute to the cognitive dysfunction. These changes include central nervous system deterioration, oxidative stress, accumulation of free radicals, and cell death. The signs are, unfortunately, progressive, and treatment is aimed at prevention and/or slowing the progression of disease, which means lifelong therapy is required once your dog is diagnosed.

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How is Sundowners in Dogs Treated?

Treatment requires a multi-modal approach, usually a combination of synergistic therapies that are based on the severity of the clinical signs. Selegiline is a prescription medication that is used to help control more severe symptoms, and it is thought to improve transmission of brain chemicals (like dopamine) as well as have protective effects on the brain’s nerve cells.

There are also commercial and prescription “senior diets” that have demonstrated improvements in cognitive function, such as Hill’s b/d ("brain diet"). Natural supplements have shown promise in managing signs and slowing the course of disease by reducing the neurological damage caused by free radicals. They include antioxidants (vitamins C and E, selenium, flavonoids), gingko bilboa, Omega-3 fatty acids, and medium chain triglycerides, to name a few. Pheromone therapy and melatonin may ease anxiety and promote a feeling of wellbeing for dogs that experience increased anxiety at night.

Finally, it’s important to keep your dog stimulated — think brisk brushing sessions, massage therapy, interactive toys, and stimulating walks. All are thought to be an important cornerstone in slowing the progression of sundowners by stimulating brain activity. Maintaining a stimulating environment and engaging in as much activity as is practical for your dog’s age and health may help prevent or delay the onset of cognitive decline as your dog moves into their golden years.

One of my favorite veterinary mantras is: “Old age is not a disease.” With proper care, our senior pups can go on experiencing a good quality of life — even as cognitive changes develop.

Dr. Shea Cox, DVM, CVPP, CHPV

Dr. Shea Cox is the founder of BluePearl Pet Hospice and is a global leader in animal hospice and palliative care. With a focus on technology, innovation and education, her efforts are changing the end-of-life landscape in veterinary medicine.

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