What You Need to Know About Sundowner Syndrome in Dogs

The advancement of Science, Technology, and Globalization in recent decades has significantly impacted the lifespan of both humans and pets. This is due to certain aspects such as improved nutrition and medication methods developed from successful research and experiments worldwide. However, such advancement impacting the lifespan of human beings and pets has come with some challenges, such as observing sundowner syndrome in dogs, which is equivalent to Alzheimer’s disease in humans.

Sundowner syndrome can affect any dog breed. However, it is more common in some breeds than others. For example, small breeds like the Poodles, which have a longer life span, commonly tend to suffer more from this condition compared to their larger counterparts like the Great Danes and Irish Wolfhounds, who have a shorter lifespan. 

In this article, we learn more about sundowner syndrome in dogs, its symptoms, possible ways of managing it, and supplements that can be helpful if your dog is suffering from this condition.

What Is Sundowner Syndrome in Dogs?

Sundowner syndrome, also known as cognitive dysfunction syndrome(CDS) or dementia in dogs, is a cognitive deterioration that is slowly progressive, especially in aging pets. It is a late-day confusion seen in dogs, mostly from late afternoon to night. It’s important to note that sundowner syndrome is not a disease but rather a combination of observable symptoms like anxiety, aggression, fear, restlessness, boredom, and confusion as sunset approaches. The change in light levels from day to night time alters your dog’s vision, thereby influencing the symptoms depicted during this time.

Not all old dogs show the symptoms of sundowner syndrome at a specific time has made it difficult to come up with the main cause of the syndrome. However, biological changes that occur as your dog ages contribute to this behavioral disorder. Among these biological changes are:

  • The accumulation of free radicals
  • Death of nerve cells
  • Deterioration of the central nervous system

Genetic factors have also been known to contribute to the occurrence of the syndrome.

Symptoms of Sundowners Syndrome

The signs and symptoms of sundowner syndrome are completely different and unique from those of down syndrome in dogs. Sundowner syndrome is a genetic behavioral disorder, while down syndrome is a chromosomal genetic disorder. Additionally, the syndrome in dogs is manifested through a combination of symptoms, most of which are associated with senile behaviors and dementia. Dogs with this disorder will frequently show confusion even in familiar places, slow or no response to calls or commands, and depict abnormal sleeping patterns. 

The symptoms of sundowner syndrome in dogs can be seen in the following changes:


This is seen when your dog acts confused and lost in a way that they get stuck in familiar places within the compound, taking longer to decide the direction to take. They will also show difficulty in recognizing their caretakers, family members, and other familiar faces, hence acting aggressively to them at times. Disoriented dogs will find it hard to get out of the kennel or house through the door even after opening it for them. You can only let your dog take their time in its undertakings in this state.

Poor interactions

Dogs with sundowner syndrome will show changes in their interactions with both humans and fellow pets. The previously-known happy and playful dog will now be seen avoiding people and acting aggressively toward other pets around the compound. At some point, the dog with the syndrome will prefer isolating himself from people and other pets.

Change of sleep patterns

This is seen when your dog starts having long naps during the day and being so restless at night. The dog will at times be seen having unnecessary barks even at the walls, causing a lot of disturbance during the day and alarm during the night. These symptoms worsen as the disorder progresses.

Behavior changes

Among the many normal behaviors you see in your dog, you will start noticing that house training is slowly getting forgotten. They will often forget to ask to be let out; they will also start licking objects, tail chasing, and answering their nature calls anywhere in the open. Their reactions to previously learned commands would also show you a significant change in their behavior even as you observe their interaction with people and pets.

When Is a Dog More Susceptible to Developing Sundowner Syndrome?

Sundowner syndrome is commonly known to take effect in dogs from 10 years of age onwards as they grow old. During the winter season, nighttime approaches earlier, resulting in sundowner syndrome in dogs due to changes in light levels.

How to Manage Sundowners Syndrome 

Dogs undergoing sundowner syndrome have a very high chance of battling this condition for the remaining part of their lives because it has no cure. For this reason, adequate care for your dog is necessary during this period of their lives by offering them specialized and adequate care. 

Below are helpful ways that can help you manage sundowner syndrome in your dog:

Consult your vet 

Consult your vet once you start observing strange behaviors and symptoms, which suggest the presence of sundowners in your dog. The vet will advise you on diets that will work best for your dog in the face of this condition. They will also prescribe medication to help manage the health problems associated with this syndrome. Consulting a veterinarian will also help unearth any other untreated conditions that may worsen sundowners’ effects.

Antidepressants and anti-anxiety medication

Over-the-counter medication such as antidepressants can be of great help to your dog. For dogs showing signs of stress, withdrawal, sleep disorders, and loss of interest in previously learned routines, antidepressants are highly recommended. Anti-anxiety medication is highly recommended if your dog has difficulty relaxing and being over-reactive. Do not give your dog any medication before consulting a veterinarian. 

Use of Selegiline

Selegiline, which is FDA approved, is another drug that is used to manage sundowner syndrome in aging dogs. It is commonly preferred because it increases dopamine levels in the brain, boosting your dog’s mood and feelings of reward and motivation. The effects of selegiline take some time before you can notice an improvement, sometimes even up to a month. 


Melatonin, a naturally occurring neurohormone that has been a sleeping aid to humans, has also been helpful for several canine conditions such as separation anxiety and changes in sleep patterns which are often a result of sundowner syndrome. Melatonin helps manage stress caused by thunderstorms, noise, and any other factors that may disrupt your dog’s sleep. However, melatonin has not yet been approved by the FDA, and neither are there enough studies of its side effects on animals. It is thus advisable to consult your veterinarian before using this regimen for your dog. 

Play and exercise

Keeping your dog actively engaged in enjoyable activities is another great way to manage the effects of sundowner syndrome. Take your dog out on walks, do regular exercise, provide them with toys, and even play memory games. This will prevent boredom and keep them active and tired enough to sleep during the right time.

Provision of proper nutrition

Specific nutrition for your dog with sundowner syndrome is also necessary. As dogs age, their blood-brain barrier, which regulates the intake of nutrients from the bloodstream into the blood cells, becomes more permeable. This increases the chances of harmful molecules getting into the brain tissues, leading to cognitive decline or nerve cell dysfunction. Food supplements like Hill’s® Prescription Diet® b/d® and Purina® Pro Plan® Veterinary Diets NC NeuroCare™ are helpful for your canine’s cognitive function.

Supplements for Sundowners Syndrome in Dogs

Both medical and herbal supplements have been found helpful in managing sundowner syndrome in dogs. However, their effects vary across dog breeds and may be more effective in some and fail to work for others. Some of the supplements that help improve cognitive function and your dogs’ quality of life when suffering from sundowner syndrome:

  • Omega-3 fatty acids
  • S-Adenosylmethionine (SAMe)
  • Medium-chain triglycerides (MCT)
  • Antioxidants
  • Denamarin
  • Silybin
  • Vitamin E
  • Cholodin
  • Solliquin
  • Melatonin
  • Neutricks 

In a nutshell

With old age comes certain conditions and gradual changes that will affect your dog’s health and well-being. If your dog is suffering from sundowner syndrome, as a pet owner, you need to provide your dog with proper nutrition, regular exercise, spending time with your pet, and lots of patience. 

Recent Posts