Why does dementia happen in pets, what are the signs and what can be done to help?

I knew my dog Jeet had Dogzheimers or doggy dementia when he would wake me five times a night to go out to pee. Then he would forget what he had gone out for. It was immensely frustrating and made me research what could be done. It turns out there was a lot I could do to help.

Why does dementia occur?

We are all rusting away!

Rusting is an oxidative reaction. All of our life systems are powered by oxidative reactions. It is the reason we breathe, to inhale more oxygen to keep those reactions going, burning fuel to provide energy for life.

Sometimes they get out of control, especially when chemical by-products called free radicals are produced. These are highly reactive compounds, often superoxides similar to hydrogen peroxide, the hair bleach. You may have seen this fizz and bubble on your skin. Skin is tough, but cell membranes aren’t, so superoxides cause a lot of damage in our body.

Not surprisingly, an organ like the brain that uses a lot of oxygen and has a lot of fat-rich cell membranes is particularly susceptible to superoxide damage. You can think of it as brain rust. Unfortunately the brain doesn’t have as much capacity for self-repair as most of our other organs.

Anyone over the age of fifty is already starting to notice the effects of this. Learning new things is becoming harder. Recall and memory is not as sharp. The first instances of the brain slipping out of gear start happening. “Ah, you’re having a senior moment,” my older clients crow, seeming pleased that another is joining the club.

Dementia is common in pets

It is happening to our pets too and is surprisingly common. In one study of dogs seven years and older, 75 percent of owners reported that their dog had showed one or more signs of dementia. However only one in eight had discussed it with their vet. Perhaps because these changes are often considered to be ‘normal’. In a survey of 154 cats over 11 years of age brought to their vet for a routine annual check, signs of brain ageing were seen in 28 percent of those aged 11 to 15, and 50 percent of those over 15 years.

The technical term for dementia is cognitive dysfunction syndrome (CDS). It is easier to recognise and study in dogs than cats. In dogs it is sometimes termed ‘Dogzheimers’ because of some similarities with Alzheimer’s disease in humans. Of course in cats it is ‘Catzheimers’! It is defined as a progressive neurodegenerative disorder and characterised by gradual cognitive decline over months and years.

It is easier to recognise early in dogs that are highly trained to perform difficult tasks. Slight deterioration in cognitive ability in these dogs is usually more easily noticed by their owners.

The signs of dementia are often grouped using the acronym DISH.

• Disorientation – Aimless wandering, ‘lost in space’ episodes, going to the wrong side (the hinge side) of the door, confusion, failure to recognise normal routines or surroundings.

• Interaction – decreased greeting of family members or visitors, decreased interest in petting or attention, decreased interest in food and other stimuli

• Sleep pattern changes – restlessness, agitation or wandering at night; increased daytime sleeping.

• Housetraining lapses – failure to ‘ask’ to go out; soiling in random places or in the presence of the owner; soiling inside shortly after going outside; incontinence.

There are other signs too, including impaired ability to work or perform tasks, decreased responsiveness to familiar commands or tricks, and slower learning or even inability to learn new tasks.

Other behavioural and disease conditions can mimic or confuse the signs of dementia.

  • Changes in the household such as a new baby, partner or pet can provoke behaviour changes similar to CDS.
  • Older pets often have poorer hearing and vision and so may be less responsive.
  • An arthritic pet may be more reluctant to perform familiar tasks, become irritable, grumpy, or start housesoiling simply because the pain of getting up and out overrides housetraining.
  • The pain of a dental abscess may cause apathy and loss of interest in food.
  • Urinary tract infections can cause urinary incontinence that may be interpreted as loss of house-training due to senility.
  • Changes in organ function are common with age and can impact on brain function and behaviour. Chronic liver disease is common in cats and dogs and can cause signs that mimic dementia.


The first step to take if you suspect your pet may be showing signs of dementia is to make an appointment with us at Halifax. Our vet will ask some probing questions, conduct a thorough physical exam and take urine and blood samples to check out organ function.

Dementia can only be diagnosed once other behavioural and medical causes have been ruled out.

Treatment options.

The treatment strategy has four components:

• Deal with any other limiting factors such as osteo-arthritis, dental pain, liver disease, urinary tract infections, etc.

• Nutritional therapies

• Use drugs if necessary

• Environmental enrichment and behavioural training


Nutritional therapies play a major role in the treatment of dementia. A number of dietary components and supplements have been found to have beneficial effects on brain function.

Phosphatidylserine (PTDS) is a component of cell membranes and is found in higher levels in brain and nerve tissue. It stabilises cell membranes, regulates neurotransmitter function and improves it in the aged. It improves the functional capacity of the mitochondria. Mitochondria are the energy production factories inside cells, and these are where most of the oxygen is used in cells. Imaging studies in Alzheimer’s patients show that they have decreased energy production in certain areas of the brain. This energy production increases significantly after supplementation with PDTS.

L-carnitine and alpha lipoic acid are two compounds that are also important in boosting mitochondrial function. Both compounds improve the efficiency of energy production by mitochondria, and decrease the production of free radicals.

The Omega 3 fatty acids DHA and EPA stabilise cell membranes and nourish brain tissue. Selenium and the vitamins C and E form part of the body’s own antioxidant defence mechanisms.

Bioflavenoids and carotenoids from many fruits and vegetables have antioxidant effects, inactivate free radicals and stabilise cell membranes.

Hill’s have produced a prescription diet called b/d specifically to counter the symptoms of dementia in dogs. It contains all of the supplements mentioned above except PTDS. It has been shown in well-controlled trials to significantly improve pets with Dogzheimers. Responses are typically seen within four weeks of feeding b/d but marked improvements are sometimes seen much sooner, probably related to increased mitochondrial energy production.

Aktivait is a nutritional supplement containing most of the discussed supplements. It has performed well in overseas trials and is available from vets in New Zealand.

Senilife contains PTDS, resveratrol and other antioxidants as well as gingko biloba, This plant contains bioflavenoids. Senilife is not currently available in New Zealand

Drugs can also be used to help pets suffering from dementia.

Nicergoline (Fitergol) improves the circulation to the brain and so benefits those patients most who are suffering from poor cerebral circulation.

Propentofylline (Vivitonin) improves cardiac output but also decreases free radicals and inflammatory substances in the brain, improves synthesis of nerve growth factor, and has been shown to improve cognition.

Selegiline inhibits the destruction of brain neurotransmitters, decreases brain cell death and increases nerve growth factor.

Because of their different modes of action varying results are seen with these drugs. Your vet may need to trial one or more, sometimes in combination.

Environmental enrichment and behavioural training can be very valuable. Our staff can help you plan activities that help your pet.

In one large study regular exercise was associated with a marked decreased incidence of dementia in dogs. This was a retrospective study so we should interpret the results with some caution. Perhaps dogs with early dementia were less willing to exercise. However this finding is consistent with the many other known benefits of exercise.

Early detection and treatment of dementia can do a lot to help our old pets enjoy their last years with improved comfort and dignity. It helps us enjoy their last years a whole lot more too!

Billy’s story

Billy was one of the gutsiest dogs you could know. Afflicted with far more than his share of medical problems, Billy bore them all with a stoic grace. For the last 15 months of his life Billy was fed Hill’s b/d and the difference was dramatic.

Billy had been showing a number of signs consistent with dementia. He would wander aimlessly and end up in a corner and keep pushing because he didn’t know where he was. He was always greatly relieved to be rescued or pulled out. His night-time wanderings caused great concern that he would drown because he would wander down to the nearby river. He soiled in the bathroom, and his owner Julia suspected that because it was a cool place Billy may have thought he was outside.

Once Billy started on Hill’s b/d the signs improved within a week. “He knew where he was and no longer had this lost look about him,” Julia commented. He no longer went out at night and the house-soiling stopped.

Best of all, his skin cleared up as well. As a West Highland terrier Billy had suffered badly from one of the curses of the breed – severe atopy or inhalant allergic dermatitis. His skin was always inflamed (“he eats himself” as Julia put it) but on Hill’s b/d he was so much more relaxed and needed lower doses of prednisone to control his symptoms. Omega 3 fatty acids have long been recognised as helping atopy so it shouldn’t have surprised us, but it did.

What happened to Jeet?

We put Jeet onto Hill’s b/d diet. Over 4 weeks that reduced his desire to go out to pee to just two times. That improved my life! Our behavioural trainer at the time, Steph Loader, started a series of weekly classes for senior dogs. These focussed on behavioural enrichment and exercises to stimulate them to think and solve problems. Jeet died peacefully in his sleep many months later.

Hans Andersen BVSc MANZCVS

dementia responds to environmental stimulation

Jeet suffered from dementia but loved daily beach walks