Dementia in Dogs and Cats: The Later Stages and Knowing When It’s Time

Most families come to this article with a diagnosis, or a strong suspicion. A dog who was house trained for years starts having accidents. A cat stops finding the litter box. A pet who always met you at the door now wanders the house, gets stuck behind the furniture, or just doesn’t seem like themselves anymore.

Veterinarians call this cognitive dysfunction syndrome, and most families know it as dementia. It’s a slow, age-related change in the brain that affects how a pet finds their way around, sleeps, uses the bathroom and relates to the people they love¹. It’s common in the oldest pets. In one study of dogs aged 11 to 16, signs in at least one of those areas went from more than a quarter of the 11- and 12-year-olds to about two-thirds of the 15- and 16-year-olds². Cats get dementia too³.

Changes like these are easy to put down to old age. Veterinary guidelines are clear, though, that old age isn’t a disease, and that changes in an older pet deserve a closer look⁴. Many dogs with signs of dementia are never diagnosed⁵, so it’s often the family who notices first.

This article covers what the later stages of dementia usually look like, how to keep a pet with dementia calm and comfortable, the signs that things are getting harder, and what families weigh as they think about the decision ahead. It’s part of our series on common end-of-life conditions.

We’ll start with how dementia changes a pet as it moves into its later stages.

Dementia affects much more than memory, and veterinarians typically group its signs into a handful of areas¹:

• Disorientation – Getting lost in familiar places, wandering without purpose, staring into space, or getting stuck in corners and behind furniture.
• Changes in how they relate to you – Some pets seek less contact or avoid being petted. Many cats go the other way and become clingier³.
• Sleep changes – Sleeping more during the day and less at night, with restlessness, pacing or crying in the evening or the small hours.
• House soiling – Accidents in the house, or outside the litter box, from a pet who was reliable for years.
• Memory and learning – Forgetting routines and things they once knew well.
• Activity changes – Pacing and wandering, or doing much less than before.
• Anxiety – Seeming worried, restless or easily startled.

A 2026 guideline from an international group of veterinary experts describes three stages of dementia in dogs¹. In the mild stage, the changes are subtle and a dog still manages daily life much as before. As it progresses, the changes become more obvious, and the household starts adjusting around them. In the severe stage, the changes are hard to miss and get in the way of basic things like getting around the house, sleeping and going to the bathroom in the right place, and the dog needs a lot of support. The guideline is written for dogs, but dementia generally progresses in cats as well⁶. One sign stands out in cats, though: they often cry and yowl more than they used to. Crying or yowling that grows louder or more frequent is one of the classic signs of dementia in cats³.

In the later stages, that might look like a dog who wanders aimlessly, stares into space, or can’t find a treat dropped right in front of them⁷. For a cat, it might be yowling from the hallway in the middle of the night, or no longer finding the litter box.

How quickly a pet reaches that point varies a great deal. In a Danish study that followed older dogs for two years, the signs got worse over time in the dogs with dementia, but at a different pace for each dog⁷. In another study, about half of the dogs with signs in one area had them in more areas when they were checked again a year or so later⁸. So nobody can give you a timeline. What you can expect is change, at your pet’s own pace.

It’s natural to wonder how much time is left. Dementia itself may not be what decides that. In two small studies of older dogs in Denmark, a dementia diagnosis didn’t shorten the dogs’ lives^9,​7. One concluded that dogs with dementia “seem to have a good chance of living a full lifespan if supported by the veterinarian and the owner”⁹. There’s no similar research in cats yet.

That means the question for many families isn’t how long dementia will give them, but how their pet is living in the meantime. Our article on understanding survival times and life expectancy covers how to think about time with any diagnosis.

Dementia rarely comes alone. Older pets often have other conditions, and some of them look a lot like dementia or make it worse. In older dogs, signs of dementia tend to go hand in hand with joint and nerve problems and with poorer health overall¹⁰. Losing sight or hearing goes along with more signs of decline too¹¹, and a pet who can’t see or hear well can easily seem lost.

In older cats, the same changes can come from common illnesses. Kidney disease, an overactive thyroid and dental disease are all common in senior cats and can go undiagnosed, and researchers urge veterinarians to ask about behavior changes, because they may point to a manageable condition rather than normal aging¹².

Pain is part of this picture too. Dementia itself may not show up as pain, but painful conditions often come with it¹⁰, and one study found that dogs became more sensitive to pain as their dementia grew more severe¹³. Our article on recognizing pain in cats and dogs covers the subtle signs to watch for.

That’s why a new change is worth a visit to your regular veterinarian, even after a dementia diagnosis. Treating pain or another illness may help a confused pet feel better. A change that appears suddenly, like falling over, walking in circles or a head tilt, doesn’t fit dementia’s slow pattern and needs a veterinarian promptly. Whatever else is going on, there’s a lot you can do to help a pet with dementia feel safe at home.

There’s no cure for dementia, though medication, diets and supplements can bring some improvement for some pets⁶. Veterinary guidelines for senior dogs and cats include managing the home environment as part of good care⁴, and for cats, keeping the things they need close and easy to reach is one of the main recommendations³.

Things to consider:

• Keep what they need close – Food, water and a comfortable bed in easy reach, and for cats, a litter box in the room where they spend most of their time³.
• Help their senses – Bumping into things and not responding to sounds are more common in severe dementia¹⁴, so the tips in our comfort care article for when sight or hearing fades apply here too, like keeping furniture where it is and letting them know you’re there before you touch them.
• Keep them safe – Swaying, trembling and falls are linked with dementia in older dogs¹⁵. A baby gate at the top of the stairs, and blocking off the gaps where they tend to get stuck, can prevent a fall or a panic.
• Keep them engaged as they’re able – Short walks with plenty of time to sniff, or a simple game, if your pet still enjoys them. In a large study of older dogs, more active dogs had milder signs of dementia, though the study couldn’t tell which came first¹⁶.
• Plan for accidents – Take dogs out more often, and give cats an extra litter box close to where they rest. Our comfort care article has more on keeping them clean.

There are also medications, prescription diets and supplements aimed at the aging brain. The research on diets and supplements is promising but uneven, and almost all of it is in dogs¹⁷. Medical advice isn’t something you should get from the internet, so this is a conversation for your regular veterinarian, who can talk through whether medication, a diet change or a supplement makes sense for your pet.

For the comforts every older pet needs, like soft bedding, good footing and help with eating, see our article on keeping your pet comfortable at home.

For many pets with dementia, the hardest hours come late in the day or in the middle of the night. This is often called sundowning: restlessness, pacing or crying that builds as the day goes on. It doesn’t always follow the sun, though. In a 2026 study of more than 200 older dogs, over half were most unsettled between 2 and 5 in the morning, and late-afternoon and evening restlessness tended to grow as dementia progressed¹⁴. Dogs with more severe dementia didn’t sleep less overall, either. They slept more in the day and less at night¹⁴.

Cats tend to show it with their voice. Crying is the most common sign owners report in cats with dementia¹⁸. When owners of cats who were crying more were asked why they thought it was happening, the most common answers were confusion and wanting attention, and very few suspected pain¹⁹.

The Restless Nights section of our comfort care article has practical ideas for these hours, like a night light, staying close and a later last trip outside. Because restlessness at night can also come from pain, anxiety or needing to go out, it’s worth raising with your regular veterinarian, who can look for other causes and talk through whether anything might help your pet settle.

Even with good care, dementia keeps moving, and over time the changes can start to outweigh what comfort care can do.

Because dementia changes slowly, and unevenly from one day to the next, it’s easy to lose track of how far things have moved. The later stages are marked by changes that get in the way of everyday life¹. These are some to watch for:

• Getting lost more often – Getting stuck, wandering without purpose, or not finding their bed, their food or the way outside⁷.
• Falls and unsteadiness – Swaying, trembling or falling, which can come with later dementia¹⁵.
• Restless nights, most nights – Trouble settling and staying asleep, which goes along with more severe dementia¹⁴.
• Accidents as part of daily life – House soiling that has become routine rather than an occasional slip.
• Anxiety that won’t settle – More time spent worried or distressed than calm. Anxiety can show up at any stage, and it’s hard on pets and families alike⁹.
• Less of who they were – Losing interest in the people, routines and things that made them who they are.

No single one of these means it’s time. What matters is the overall picture, and how it changes over weeks and months. The section of our comfort care article on when comfort isn’t enough anymore describes more of the general signs.

That’s where tracking helps. There are rating scales built for dementia, like the Canine Cognitive Dysfunction Rating scale, a short questionnaire owners fill in that is useful for tracking change alongside your veterinarian’s exam²⁰. These scales are for tracking, not for diagnosing at home, and different scales can give different results¹³. For the bigger picture, a quality of life scale or the free Hospet app lets you record good days and bad days and see how things are trending. Our article on tracking your pet’s quality of life explains how, and our short video “A free tool for tracking your pet’s quality of life” shows how Hospet works.

Try to fill in your tracking at the hardest times of day, not only the easiest. If different people in your home see your pet at different hours, comparing notes gives a truer picture, as our article on when family members disagree about euthanasia explains.

If the picture is hard to read, our veterinarians offer an in-home quality of life consultation. In a full, unrushed hour in your home, we can see how your pet finds their way around familiar rooms and talk through what happens in the hours we won’t be there to see.

Tracking shows you what’s changing. Deciding what it means is harder, and with dementia, a few things make the decision feel different.

With many conditions, pain is the main thing to watch for. Dementia itself may not look painful, but fear, confusion and anxiety are suffering too. As our euthanasia timing page puts it, “having a physical body that is functioning normally, and a mental state free of anxiety or confusion are essential to a good quality of life.” Researchers who followed dogs with dementia in Denmark singled out anxiety as “especially stressful to both dog and owner”⁹.

Because dementia may not shorten a pet’s life on its own, the decision usually isn’t about the disease running its course. It’s about how your pet is living. Our article on the euthanasia window describes timing as a window rather than a single perfect moment, and that way of thinking fits dementia well.

The ups and downs can make it harder. A pet may seem almost like themselves at breakfast and be lost and restless in the middle of the night. Both are real, and it’s very normal to want to play down the bad moments and elevate the good ones in our minds. That’s part of why tracking what you see in your pet is so important to staying on top of their quality of life.

Caring for a pet with dementia is a lot of work, and it’s OK to say so. Keeping them safe, cleaning up accidents and getting up in the night all add up. In a study of people caring for dogs with dementia, about one in six carried a level of strain that researchers consider clinically significant, and the strain was greater when the dementia was more severe²¹.

While it’s normal to want to put your pet’s needs above your own, your limits are a fair part of the decision, too. In our webinar “When Is It Time? Understanding the Euthanasia Window”, we talk about families whose own health limits the care they’re able to give: “that’s not a shortcoming on your part. It’s just the reality that we find ourselves in.” Being honest about what caring for a pet with dementia asks of you isn’t selfish. That honesty can help you build a care plan you can keep up with, and the feline senior care guidelines make a similar point: care plans should be built around what is reasonable and practical for each family²².

It’s not just the care itself that’s hard. Many people also find they’re grieving before their pet is gone. In a study of owners of senior dogs, with and without dementia, that early grief was tied to the strain of caregiving and how close they felt to their dog, rather than to how far the dementia had gone²³. Our article on anticipatory grief talks more about this.

Knowing what the goodbye itself will look like, whenever it comes, can take a little of that weight off. If you’re considering a goodbye at home, What Happens During In-Home Euthanasia walks through the visit step by step, and our guide to preparing for an in-home euthanasia covers the practical side.

Dementia changes a pet slowly, and often unevenly, so it can be hard to see how far things have come. Knowing what the later stages look like, keeping your pet’s world safe and familiar, and tracking the changes over time can all make that picture clearer.

Lean on your regular veterinarian for the medical side, including checking for pain or other illness along the way. And please be gentle with yourself. Caring for a confused pet asks a lot of you, and it’s OK to need support along the way.

→ Tracking Your Pet’s Quality of Life: Why It Matters and How to Do It
Practical frameworks to objectively measure your pet’s comfort, happiness, and wellbeing over time.

→ Keeping Your Pet Comfortable at Home
Practical comfort care for a sick or aging pet, from footing and bedding to eating, breathing and medications.

→ The Euthanasia Window: Understanding When It’s Time
Why there’s no single “perfect moment,” and how to think about timing as a window rather than a moment.

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