Senior Dementia in Dogs

Causes, Treatment, and Prevention

Senior dog

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Senior dementia is a common problem occurring in older dogs just as it does in aging humans. Similar to Alzheimer's in people, dementia in dogs is a degenerative brain condition that causes altered behaviors and memory loss. These progressive changes affect the quality of life for both dogs and their owners. There is no cure for dementia, but owners may be able to lessen the negative effects and help their dogs live happily for a little while longer.

What Is Senior Dementia?

Senior dementia, formally known as canine cognitive dysfunction syndrome (CDS), is a collection of symptoms resulting from progressive brain degeneration that causes changes in a dog's mood, behavior, and memory.

The Behavior Clinic at the University of California at Davis states that 28% of dogs aged 11 to 12 years display signs of dementia and that likelihood increases to 68% of dogs when they reach ages 15 or 16.

Symptoms of Senior Dementia in Dogs

Dementia negatively affects the everyday life of a senior dog and is commonly seen to varying degrees as dogs age. Some symptoms may appear and worsen gradually as the dog ages, or they may occur more suddenly and be more drastic.


  • Soiling in the house
  • Getting lost in the house/disorientation
  • Barking without reason
  • Going to the wrong side of the door
  • Lack of interaction with people or other pets
  • Decrease or lack of appetite
  • Lower threshold for aggressive behavior
  • Anxiety
  • Irregular sleeping patterns
  • Staring at the walls
  • Pacing/repetitive behaviors

One of the biggest concerns that dog owners have is the loss of house training. As some dogs develop senior dementia they get confused and may start urinating or defecating in the house. This causes frustration for the owner who may in return get upset with their pet. This affects the human-animal bond and ultimately the quality of life of both the pet and the owner.

Other signs of confusion due to senior dementia include disorientation in the home, staring at walls, and going to the hinged side of a door when the dog has known for years which side of the door opens to go through it. Senior dementia can cause a dog who has known its home environment for its entire lifetime to suddenly get lost in rooms or corners of its house.

Vocalizations, including barking, whining, and crying for no apparent reason, are also common in dogs with senior dementia. This may be an indication of stress, fear, or anxiety due to confusion; they may also show aggression.

Aggressive behaviors may be more common in dogs with dementia due to their lowered threshold of tolerance and patience. Normally patient and willing dogs may suddenly growl or bite at familiar people and pets.

Irregular sleeping patterns, repetitive behaviors such as licking and pacing, a decrease in appetite, and not wanting to interact with other pets or their owners can be additional signs of senior dementia in dogs. These behaviors can strain relationships owners have with their dogs.

The most common signs of senior dementia can be remembered with the commonly used acronym DISHA: disorientation, interaction changes, sleep changes, house soiling, and activity level changes.

Signs of Dementia in Dogs

The Spruce / Elnora Turner


No one completely understands the complex causes of dementia in dogs or humans. The symptoms of dementia are a result of changes or damage in the brain, but different manifestations of dementia may arise from different brain issues.

Sometimes, certain proteins accumulate in the brain around neurons, causing cognitive decline. The breakdown of neurons is another age-related factor in disrupting the normal transmission of information in the brain.

Diagnosing Senior Dementia in Dogs

Your veterinarian will rule out other medical issues, such as tumors or diseases, before diagnosing your dog's dementia. Sometimes, a questionnaire will be used to pinpoint behavioral signs that are common in this condition, so your careful attention to signs of dementia will be vital in achieving a diagnosis.

The Quality of Life Scale, or HHHHHMM Scale, is often used to aid owners in determining whether or not their dog has changed as it ages. This scale goes through the signs of dementia and includes a review of the dog's behaviors. Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility, and More good days than bad are assessed on the HHHHHMM scale.

This scale helps an owner decide whether or not a pet's quality of life is still good as dementia progresses and may also help an owner decide when euthanasia should be considered.

Treatment and Prevention

There is, unfortunately, no way to reverse the signs of dementia in dogs but there are some nutritional aids that can be administered to help potentially delay brain changes as a dog ages. Antioxidants, omega-3 fatty acids, vitamin E, and medium-chain triglycerides (MCTs) are the main dietary components that are often discussed for brain health.

Other supplements used to support brain health and manage symptoms of dementia are SAMe, Denamarin, Silybin, and Cholidin.

Some experts recommend supplementing dogs' diets before they begin to show signs of senior dementia, but there is little evidence that this works as a fully preventative regimen. If you are concerned with CDS developing in your senior dog, talk with your veterinarian about possible preventative supplements.

Prognosis for Dogs with Senior Dementia

Dementia is a progressive condition that can, at best, be stabilized for a period of time. No matter how supportive owners are or how diligent they are in providing brain-healthy supplements, the process of aging will further deteriorate their dogs' brains. Once dementia becomes severe and negatively impacts the quality of life, most owners will have to make the difficult decision to euthanize their dogs.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Helping Our Senior Dogs Age Gracefully. VCA Animal Hospital.

  2. Neilson JC, Hart BL, Cliff KD, Ruehl WW. Prevalence of behavioral changes associated with age-related cognitive impairment in dogs. Journal of the American Veterinary Medical Association. 2001;218(11):1787-1791.

  3. Cognitive Dysfunction Syndrome. Indoor Pet Initiative.

  4. Dog Gone Day. Washington State University Magazine.