Cushing’s Disease in Dogs: Behavior Changes to Know

Has your older dog started pacing at night, drinking bowl after bowl of water, or having accidents indoors after years of being clean? It’s easy to shrug these off as “just getting old.” But sometimes they point to something treatable: Cushing’s disease. And often, it’s the behavior changes — not the physical ones — that owners notice first.

Cushing’s disease in dogs is a hormonal condition that quietly changes how your dog acts as well as how they look. In this guide we’ll walk through exactly which behavior changes to watch for, why they happen, how to tell them apart from normal ageing, and what to do next. Everything here is drawn from trusted veterinary sources, but it’s written for you, the owner — and it’s here to inform, not to diagnose. Your vet is always the right person to confirm what’s really going on.

Key Takeaways

Quick answer: Cushing’s disease (hyperadrenocorticism) can cause noticeable behavior changes in dogs – increased hunger, restlessness, panting, and sometimes irritability – driven by excess cortisol rather than a training or temperament problem. A vet diagnosis through bloodwork is needed to confirm it.

Key Takeaways

• Cushing’s is caused by chronically elevated cortisol, most often from a pituitary or adrenal gland tumor.
• Behavioral signs often appear alongside physical ones: increased thirst and urination, a pot-bellied appearance, and thinning coat.
• Increased appetite and food-seeking behavior in Cushing’s dogs is a hormonal response, not disobedience.
• Diagnosis requires specific vet testing (such as an ACTH stimulation test or low-dose dexamethasone suppression test), not just symptom observation.
• Treatment (medication or, less commonly, surgery) often improves behavior alongside physical symptoms once cortisol levels are managed.

Why Trust This Guide?

This guide reflects standard veterinary endocrinology understanding of canine Cushing’s disease, intended to help owners recognize when behavior changes warrant a vet workup rather than to replace professional diagnosis.

• It’s a hormone problem. Cushing’s disease means the body makes far too much cortisol.
• Behavior often changes first. More drinking, more urinating, restlessness, and lethargy are common early clues.
• It mostly affects older dogs, and the slow onset is easily mistaken for normal ageing.
• It’s usually manageable, not curable. Most dogs need lifelong medication and regular monitoring.
• Only a vet can diagnose it. Specific blood and urine tests are needed to confirm it.
• Early action helps. Catching it sooner protects your dog’s quality of life.

Table of Contents

• What is Cushing’s disease in dogs?
• What behavior changes does Cushing’s cause?
• Why does Cushing’s change a dog’s behavior?
• Is it Cushing’s or just old age?
• When to see your vet
• How is Cushing’s diagnosed and treated?
• Helping your dog live well with Cushing’s
• Common mistakes to avoid
• Frequently asked questions

What Is Cushing’s Disease in Dogs?

Cushing’s disease, known medically as hyperadrenocorticism, is a hormonal disorder in which a dog’s body produces too much cortisol. Cortisol is a natural hormone that helps manage stress, metabolism, and the immune system — but in excess, over months and years, it damages the body and changes behavior.

There are three main forms. The most common is pituitary-dependent, caused by a usually benign tumour on the pituitary gland at the base of the brain, which drives the adrenal glands to overproduce cortisol. Less commonly, a tumour on an adrenal gland itself is to blame. The third form is iatrogenic, meaning it’s caused by long-term use of steroid medication rather than a tumour.

It mainly affects middle-aged and senior dogs, and because the signs build slowly, they’re often missed or blamed on age. That’s exactly why knowing the behavioral clues matters so much.

What Behavior Changes Does Cushing’s Cause?

The behavior changes of Cushing’s disease are often what first prompt a worried owner to call the vet. Most trace back to the excess cortisol affecting thirst, appetite, energy, and the body’s systems. Here are the ones to watch for.

• Drinking a lot more water. Excessive thirst is one of the most common signs, seen in the large majority of affected dogs.
• Urinating more, and indoor accidents. With all that extra water comes more urine, and a previously house-trained dog may start having accidents.
• A noticeably bigger appetite. Many dogs become hungry all the time, begging or scavenging more than usual.
• Restlessness and night-time anxiety. Some dogs pace, seem unsettled, or struggle to settle at night.
• Lethargy and low energy. Others slow down, tire easily, and seem less interested in play or walks.
• Excessive panting. Panting when it isn’t hot or after little exertion is a common feature.

In advanced cases where a pituitary tumour grows larger, neurological signs such as circling, disorientation, or seizures can appear — though these are much less common. Any of these warrants prompt veterinary attention.

Why Does Cushing’s Change a Dog’s Behavior?

Almost every behavior change in Cushing’s traces back to one thing: too much cortisol circulating in the body, day after day. Understanding the “why” makes the changes far less mysterious and helps you describe them accurately to your vet.

Excess cortisol makes a dog drink more, which in turn makes them urinate more — so the thirst and the indoor accidents are two ends of the same chain. The hormone also stimulates appetite, which is why so many dogs seem constantly hungry. Over time, cortisol breaks down muscle, leaving dogs weaker, less active, and more lethargic, while the strain it puts on the body contributes to panting and restlessness. In short, your dog isn’t misbehaving — their body is being pushed out of balance.

Is It Cushing’s or Just Old Age?

This is the question that trips up most owners, because Cushing’s develops slowly and its early signs look a lot like a dog simply slowing down with age. The difference is that normal ageing is gradual and mild, while Cushing’s tends to bring a cluster of specific, worsening changes — especially the dramatic increase in thirst and urination. The table below shows how they typically compare.

If several of the “possible Cushing’s” signs ring true, it’s worth a vet visit — not to panic, but to check. As one veterinary teaching hospital puts it, when ageing isn’t the whole answer, asking the question early is what protects your dog.

When to See Your Vet

Book a veterinary appointment if you notice a lasting increase in thirst, urination, or appetite, new indoor accidents, unexplained hair loss, a swollen or pot-bellied appearance, or persistent panting. On their own, any one of these has many possible causes; together, they build a picture worth investigating.

Seek prompt veterinary attention if your dog shows neurological signs such as circling, disorientation, staring, or seizures, as these can indicate a more advanced problem. The earlier Cushing’s is identified, the sooner treatment can ease the symptoms and improve your dog’s daily comfort.

How Is Cushing’s Diagnosed and Treated?

Cushing’s cannot be diagnosed on symptoms alone, because many conditions look similar. Vets usually begin with routine blood tests and a urinalysis to rule out other diseases, then use specific hormone tests to confirm Cushing’s and work out which type it is. Identifying the form matters, as it guides treatment.

Most dogs are managed with lifelong medication that lowers cortisol production, alongside regular monitoring blood tests to keep the dose right. In selected cases, surgery may be an option. While Cushing’s usually can’t be cured, successful treatment often brings real improvements — less thirst, fewer accidents, reduced panting, and better energy — giving many dogs a good quality of life for years.

Helping Your Dog Live Well With Cushing’s

A Cushing’s diagnosis sounds frightening, but with treatment and a few sensible adjustments at home, most dogs settle into a comfortable routine. Your job as an owner is mainly to support the treatment and keep a close eye on the behavior changes that tell you how well it’s working.

1. Give medication exactly as prescribed. Consistency keeps cortisol under control; never adjust the dose yourself.
2. Keep every monitoring appointment. Regular tests let your vet fine-tune treatment and catch problems early.
3. Always allow free access to water. The thirst is real; manage the urination with more frequent toilet breaks instead.
4. Offer more toilet opportunities. Extra walks or garden trips reduce accidents and stress for both of you.
5. Watch the behavior signals. Improvement in thirst, appetite, and energy is a good sign; a return of symptoms means it’s time to call the vet.
6. Support their comfort. Soft bedding and gentle, regular exercise help dogs coping with muscle weakness.

Common Mistakes to Avoid

• Blaming everything on old age. Owners often assume increased thirst and slowing down are just ageing. This delays diagnosis and lets the disease progress. When several signs appear together, get them checked.
• Restricting water to stop accidents. This is dangerous. The thirst is driven by the disease, and limiting water can leave your dog dehydrated. Manage the urination instead, and treat the cause.
• Stopping medication once symptoms improve. Cushing’s is managed, not cured. Symptoms return if treatment stops, so medication and monitoring continue for life.
• Skipping monitoring tests. These aren’t optional extras. The wrong dose can be harmful, and only regular testing keeps it right.
• Self-adjusting steroid medication. Changing steroid doses without your vet can trigger or worsen problems. Always change them under guidance.

Frequently Asked Questions

What are the first behavior signs of Cushing’s in dogs?
The earliest signs are usually increased thirst and urination, a bigger appetite, and sometimes restlessness or lethargy. Because they build slowly in older dogs, they’re often mistaken for ageing. A lasting cluster of these changes is worth a vet visit to investigate.

Can Cushing’s disease make a dog aggressive or anxious?
Cushing’s more often causes restlessness, night-time unease, and lethargy than outright aggression. However, any dog that feels unwell can become irritable. If your dog’s temperament changes noticeably, tell your vet, as it helps build the overall picture.

Is Cushing’s disease in dogs painful?
Cushing’s itself isn’t typically described as painful, but it reduces quality of life through excessive thirst, muscle weakness, skin problems, and infections. It can also worsen existing conditions like arthritis. Treatment aims to relieve these effects and keep your dog comfortable.

How long can a dog live with Cushing’s disease?
Many dogs live comfortably for years with proper treatment and monitoring. Prognosis depends on the type, the dog’s age, and other health issues, so your vet is best placed to advise. Early diagnosis and consistent management give the best outlook.

Is Cushing’s disease in dogs curable?
In most cases it’s managed rather than cured, with lifelong medication controlling cortisol levels. Some adrenal-type cases may be treated surgically. Even without a cure, well-managed dogs often enjoy a good quality of life for a long time.

What happens if Cushing’s is left untreated?
Untreated, excess cortisol gradually damages the body and erodes quality of life, increasing the risk of infections, muscle wasting, and other complications. Because it’s progressive, earlier treatment generally leads to better comfort and outcomes for your dog.

Should I limit my dog’s water if they’re urinating indoors?
No. The increased thirst is caused by the disease, and restricting water can be harmful. Instead, provide more frequent toilet breaks, protect floors while you seek help, and speak to your vet about treating the underlying cause.

Sources & References

• PetMD — Cushing’s Disease in Dogs: Symptoms and Treatment
• American Kennel Club (AKC) — Cushing’s Disease in Dogs
• University of Illinois College of Veterinary Medicine — Cushing’s Disease in Dogs
• PDSA and Blue Cross — dog health and hyperadrenocorticism guidance

Final Thoughts

The behavior changes of Cushing’s disease — the endless thirst, the accidents, the restlessness, the tiredness — are easy to write off as your dog simply growing old. But they’re often your dog’s way of telling you something has shifted, and that early conversation with your vet can make a real difference to how well and how comfortably they live.

Cushing’s is usually manageable, and with the right treatment many dogs go back to feeling much more like themselves. Trust what you’re seeing, keep notes, and don’t be afraid to ask the question. For more caring, practical guidance, explore our other dog health and care guides, and browse the wider pet care section for support through every stage of your dog’s life.

Not every behavior change traces back to a medical cause like Cushing’s. If a dog’s barking has simply become a chronic nuisance, our guide to what to do about constant dog barking covers the more common, non-medical triggers.

Weight changes are also worth watching in dogs with Cushing’s disease, since the condition affects metabolism and body composition. If weight management becomes a concern alongside a Cushing’s diagnosis, our guide to safely helping your dog lose weight covers vet-backed calorie targets and feeding structure.