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Is Mental Illness a Thing for Dogs?

As people, we understand the importance of good mental health in leading a functional and enjoyable human life. 

The term “mental illness” encompasses a range of diseases and conditions in people, but classifying them is not straightforward. 

When is something a mental health condition, compared to what we consider “normal” human behaviour? One of the answers lies in the way in which the person copes with the condition. If their mental state leads them to feel distress, and/or impairs their ability to function in life, then they may be suffering from a clinical condition.

For people, the American Psychiatric Association defines mental illness as all diagnosable mental disorders [1] — health conditions involving:

1) Significant changes in thinking, emotion and/or behaviour.

2) Distress and/or problems functioning in social, work or family activities.

So what about dogs? Do they have mental health conditions? Well, if we take the same idea as for human mental health (distress and/or impaired ability to function in life), then the answer is YES! 

There are a range of well documented conditions in dogs that are characterised by high levels of anxiety or fear, which absolutely cause distress and an impaired ability to function.

These dogs can be anxious, fearful or stressed on a daily basis; while simply living the normal everyday life of a dog that many of us envy. Things we think of as idiosyncrasies of a dog’s personality, such as barking at the postman or tearing up the couch when left home alone, could actually be a cry for help from the dog.

I can hear some people reading this and already saying “isn’t this a bit over the top? They’re just dogs for goodness sake!”… This is a totally understandable reaction to just finding out that people have been so bad at understanding their dogs for most of humanity that we never knew this before.

It is almost unbelievable that after co-evolving with dogs, we are only now as a society just waking up to the fact that when they are distressed, panicking or fearful, that they might feel bad and be difficult to look after or train. Dogs can be affected by almost all the physical diseases that affect people, so why not mental health diseases too? 

Seriously, dogs get kidney disease, heart disease, lung disease, skin disease, infections, cancer, immune disorders, nutritional deficiencies, dental disease, obesity, diabetes, food poisoning, birth defects, and the list goes on. 

All the parts of the brain that are involved in human mental health conditions are present in the dog brain too. So why then wouldn’t dogs also get mental health conditions too?

If we are on the same page now, and you agree that it makes sense that dogs would get mental health conditions, just as people do, then here is another question. What would the dogs with mental health problems look like? How might you expect them to behave? 

Unsurprisingly, the answer is distressed, anxious or fearful dogs, that are often difficult to control or behave in ways that are disruptive or dangerous. 

These dogs will be showing signs of these negative emotions in their body language – which doesn’t lie by the way. 

As dogs aren’t smart enough to lie (without human assistance), reading their body language is always an accurate indicator of how they are feeling emotionally. They can’t pretend to smile, or fake an angry scowl like people can. 

Signs of fear and anxiety can include pacing, panting, hiding, trembling, pulling on the leash, destructive behaviour, escaping, barking, growling and even biting (all behaviours that every dog does).

Many dogs show these behaviours that could be anxiety related, so doesn’t that mean that all dogs are anxious? The answer is yes and no. A lot of behaviours that can indicate negative emotions, like those above, can also occur for other reasons too. 

However, all dogs do experience anxiety. Just like all people experience anxiety from time to time. It’s a normal emotion. When a dog displays some potentially anxiety-related behaviours, they may be experiencing the normal dog emotion of anxiety. 

If you have a dog, and never notice that they are anxious, then you do not have a rare dog that doesn’t ever feel one of the most primal and basic emotions. Rather, you are unable to read the emotions of your dog well enough to see when they are feeling worried. Some dogs I meet are living in a constant state of anxiety, leading the owners to thinking that their behaviour is just normal, because it happens all the time!

So if all dogs feel anxiety at least some of the time, then what does a dog with a mental health condition look like? This is a tricky question to answer precisely, so I refer back to the human definition of the term by the American Psychiatric Association above. If their mental state leads them to feel distress, and/or impairs their ability to function in life, then they may be suffering from a clinical condition.

So, what might an “impaired ability to function in life” look like for a dog? I take this as a way of behaving that causes the dog to actually have a reduced level of welfare as a consequence of the actions they are taking. Here are a few examples:

If a dog fearfully bites another dog on a walk, their owner is less likely to take the dog on walks in the future.

✔️ If a dog chews up all their bedding, then they don’t have a bed to lie on anymore, and it might not be replaced if they keep destroying them, and may be kept outside the house.

✔️ If a dog bites visitors who come over to the house, the owner is more likely to spend more time away from the house to socialise with people.

✔️ If a dog is aggressive or won’t sit still at the vet, they are more difficult to treat and less likely to be treated.

✔️ If a dog barks all day in the backyard, the dog is more likely to be rehomed.

These examples are not the same as human self-sabotaging behaviours, as the dog is not aware on any level that their behaviours are causing self-harm. So, you can imagine that if a dog was doing all the things from that list above, their life has the potential to be locked up at home, with no bed, not getting walked, with an owner that is always out away from home, and which can’t even get good treatment at the vet. This dog would have a poor quality of life, and be a high likelihood for being rehomed.

When veterinarians decide which dogs have the label of a “clinical behaviour disorder”, it can be a bit subjective. This is because there is no definition of just how distressed or impaired a dog needs to be considered clinically over the line. 

You can imagine there would be some dogs that are a bit distressed and slightly impaired, which might be over diagnosed as being unwell when they are just a bit highly strung. Even excluding these cases, where there could be debate over whether they are affected enough by their mental health, there are a huge number of other dogs that are very severely impacted

These dogs are often euthanised at animal welfare shelters at a young age. 
In fact, for dogs under the age of three, their undesirable behaviours are the most common cause of death [2]. 
Keeping in mind the definition above [1], these dogs have been affected by their mental health enough to lead to their own death. The severity of these cases can be compared to human mental health cases that also lead to death – think how severely affected someone needs to be before they actually die. For me, as a Vet with a PhD in dog behaviour, I can say that every one of these dogs was suffering mentally a great deal prior to being given up by their human family.

So what causes these mental health conditions in our dogs? 

Surely it is the owners – us – who are at fault? The answer is once again, “yes and no”! 

For a very quick rundown, I can say that in most cases people haven’t caused their dog to get their mental health condition, however the owner can influence how well managed the condition is. I often speak to people who have had many dogs across their whole life, and treated them all the same way, and then one day they happen to get a dog that is impossible to manage. 

Just like susceptibility to mental health illness is heritable in people, so too do dogs inherit these traits.

Understanding and treating dogs well to cater for their mental health can’t eliminate the problem, but it can help reduce the number of dogs affected. 

We should be focusing on reducing the fear, anxiety and stress in our dog’s lives, to help them live a happy and functional life. 

Happy and relaxed dogs are also easy to live with. 

Ensuring good mental health in your dogs really is win-win. 

To further explore how mental health affects the dogs in our lives you can read my book, titled “A Dedication to Difficult Dogs: A heart-warming tale shedding light on canine mental health”.

If you need help decoding your dog's emotions, this is your chance to win 1 of 4 copies of "A Dedication to Difficult Dogs" in our book competition closing 17/01/2024.

written by Dr Dennis Wormald, January 2024 for Australian Dog Lover Magazine (all rights reserved).


1. American Psychiatric Association website. What is mental illness? Accessed 28/12/2023.

2. Boyd C, Jarvis S, McGreevy PD, et al. Mortality resulting from undesirable behaviours in dogs aged under three years attending primary-care veterinary practices in England. Animal Welfare. 2018;27(3):251-262. doi:10.7120/09627286.27.3.251

About our writer

Dr Dennis Wormald, BVSc (hons), PhD (canine anxiety), MANZCVS (Veterinary Behaviour) is a Veterinarian with a PhD exploring canine anxiety, from the University of Melbourne, Australia. 

He is a member by examination of the Veterinary Behaviour Chapter of the Australian and New Zealand College of Veterinary Scientists. Dr Wormald enjoys working as a veterinarian doing private veterinary referral behaviour consulting for dogs in Melbourne, Australia.
He is the Founder of ABAdog® - where no dog is a bad dog. For more information, visit

You can follow him on Facebook at and on Twitter at

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