Vet Talk: Could your ‘misbehaving’ pet be in pain?

SINGAPORE –It is not uncommon for pets to be described as naughty.

From the cat that urinates and defecates outside the litter box to the dog that snaps for seemingly harmless reasons like being petted – the list of bad behaviours goes on. 

However, such labels are rarely helpful when one is trying to understand why one’s furry companions behave the way they do. 

To truly address behavioural issues, one must probe further and identify the root causes of these behaviours, instead of just focusing on the outward behaviour.

Behaviour a clue to medical issues

An often-overlooked cause of behaviour problems is underlying medical issues. Behavioural and medical problems are closely interlinked and are two sides of the same coin.

In fact, changes in behaviour are often the first clue that an animal may be unwell.

For example, you may notice your usually friendly and outgoing labrador retriever becoming withdrawn, less energetic or suddenly aggressive towards family members. Instead of dismissing this as “naughtiness”, further investigation may reveal pain or another medical issue driving the behaviour.

Pain is a common culprit

Pain-related medical conditions are a common culprit. Pain can manifest as aggression, increased anxiety or heightened reactivity.

According to Professor Daniel Mills, a leading veterinary behaviourist and researcher at the University of Lincoln in Britain, many behavioural problems in pets are either directly caused or worsened by physical pain.

Research supports this position. In one international study of behaviour referrals, up to 80 per cent of cases showed confirmation or diagnosis of pain.

Pain affects not only an animal’s comfort, but also its cognitive and emotional well-being. Animals in pain may learn more slowly, experience heightened anxiety and be more easily triggered.

The challenge is that pain is not always obvious, even to professionals, and is frequently underdiagnosed or under-reported.

The signs that suggest your pet might be in pain include:

Other medical factors that affect behaviour

Of course, pain is not the only medical factor influencing behaviour. Neurological conditions, such as cognitive dysfunction syndrome, can cause excessive vocalisation, disrupted sleep and increased anxiety in older dogs and cats.

Skin conditions like canine atopic dermatitis in dogs are linked to higher rates of behavioural problems, which are suggested to be due to stress. 

Gastrointestinal disorders, including gluten intolerance, have been associated with aggression in dogs.

Increasingly, research has also shown a link between the bacteria in an animal’s gut and its behaviour (the gut-brain axis).

A 2022 study published in the Frontiers In Psychiatry journal noted that probiotics can help reduce anxiety in rats, while a 2011 study found that probiotics can improve mental health in humans.

A separate study conducted in 2019 with a small population of dogs in an animal shelter showed significant differences in the composition of gut microbiota (microbes that live in the gut) between aggressive and non-aggressive dogs.

Although the study does not determine cause and effect, it presents an interesting association between gut microbiome and animal behaviour. It also sets the stage for future studies to explore this link.

While much remains to be discovered, these findings highlight the extent to which medical and behavioural issues are intertwined. 

Why behaviour and medical cause cannot be separated

For pet owners, this means recognising that behaviour problems are not always purely training issues.

Sometimes, addressing the underlying medical cause is all that is needed to resolve the behaviour. Without this step, attempts at training, especially if aversive methods are used, will not only fail, but may also worsen the animal’s behaviour and welfare.

The best approach is to consult both your veterinarian and a qualified trainer or behaviour consultant when tackling behavioural concerns. Always seek professional help early whenever possible.

Dog owners can refer to the list of dog trainers under the Animal & Veterinary Service-Accredited Certified Dog Trainer Scheme, which was launched in December 2022 as a benchmark for competency in dog training. The list is available at

go.gov.sg/acdt

For industry professionals, collaboration is key. Veterinarians, trainers and behaviour consultants must work hand in hand to ensure behaviour issues are addressed holistically and effectively, with both medical and behavioural expertise. Such partnerships are invaluable in helping animals and supporting the families who care for them.

So, the next time your pet “misbehaves”, pause and ask yourself: Could my pet be in pain?