Is It A Behaviour Issue Or A Symptom Of Chronic Pain In Dogs?

Why pain should be ruled out before behaviour labels, training plans, or anti-anxiety medication

Is your dog reactive, restless, or constantly “busy”? Maybe they bark at noises, struggle to settle, or act differently than usual. It's not always a matter of lack of training.

More often than not, these changes start in the body, not the brain.

Muscle pain, joint pain, gut discomfort....

When a dog is in discomfort, their behaviour changes. And until that discomfort is addressed, modifying behaviour can feel incredibly hard — sometimes impossible — no matter how experienced the trainer or how committed the owner.

Examples of behaviours that can hint at pain:

• Reactive dog behaviour (barking, lunging, snapping)

• A shorter fuse or reduced tolerance

• Trouble settling or switching off

• Constant busyness or high arousal

• Changes in movement, posture, or willingness to rest

• Hesitance to grooming or sensitivity to touch

• Noise sensitivity, like vehicles, children, loud bangs

  
  

Some dogs have always behaved like this, and owners accept it as their normal , which can make it harder to spot underlying pain.

Anti-anxiety medication and training can both play a role, but if a dog’s behaviour is caused by pain, treating only the brain won’t solve the problem. It’s about making sure we understand what is driving the behaviour.

Reactivity and Pain

Reactive dog behaviour — barking, lunging, snapping, freezing, or over-alert behaviour is often treated as a behavioural or emotional problem. But for many dogs, it is a symptom of chronic pain in dogs, not the root issue.

Pain, discomfort, or physical strain keeps the nervous system on high alert. Thresholds shrink. The dog has less capacity to cope with normal stressors. What was once manageable, suddenly isn’t.

From the outside, this looks like reactivity. From the inside, it’s the body saying, “I’m already overloaded.”

This is why some dogs show improvements in reactivity once physical discomfort is addressed — sometimes more than training alone ever achieved.

A Hard Truth From My Own Home

My own spaniel was diagnosed with hip dysplasia at eight years old.

That’s not an easy sentence for me to write. I’m a dog trainer. I work with behaviour every day. And yes — it’s uncomfortable to admit that I didn’t see it sooner.

For years, she looked like a “busy spaniel”: high arousal, always moving, never fully settled. She wasn’t reactive. She wasn’t aggressive. She wasn’t “a problem dog”.

She had been examined multiple times by vets over the years, and nothing obvious showed up. Busy dogs are hard to assess, and many dogs are tense or alert at the vet, which can make subtle discomfort even harder to notice.

Looking back, she was self-medicating with arousal. That constant movement and intensity dulled the pain temporarily.

By the time she started showing clearer signs, X-rays confirmed hip dysplasia. By then, the pain must have been significant. Dogs don’t show pain early — they hide it incredibly well.

It took three months to get her medication right, adding one drug at a time, to finally give her a comfortable, manageable life.

Looking back, I sometimes think that if she had shown bigger behaviour problems, I might have noticed sooner. But she was blessed with excellent genetics — naturally tolerant, patient, and able to mask her discomfort for years.

Dogs are designed for survival. And survival means hiding weakness.

How Dogs Self-Medicate With Arousal

When dogs “self-medicate with arousal”, it isn’t a choice — it’s biology.

Ongoing discomfort sends constant stress signals from the body to the brain. Over time, this keeps the nervous system in a heightened state. The dog may appear restless, driven, busy, or unable to settle.

High arousal releases chemicals like adrenaline and dopamine. These increase focus and drive, but they also temporarily dull pain signals. In simple terms, when the dog is busy, moving, excited, or highly engaged, they feel the pain less.

So the nervous system learns something important: don’t slow down.

This is why some dogs look fine when working, running, or training — but struggle when they stop. Stillness makes the discomfort louder.

From the outside, this often gets labelled as hyperactivity, poor impulse control, anxiety, or reactivity.

From the inside, it’s survival.

Why Settling Is So Hard for Some Dogs

True relaxation requires safety.

To settle, the nervous system needs to switch into a rest-and-repair state. But if slowing down makes discomfort more noticeable, the brain won’t allow it.

Instead, we see:

• dogs who pace or constantly reposition

• dogs who struggle to lie down comfortably

• dogs who can’t “do nothing”

• dogs who always seem switched on

• dogs who react strongly to noises

This isn’t defiance. It’s protection.

Diagnosing Chronic Pain Can Take Time

Chronic pain can be subtle and hard to detect. Sometimes it takes weeks of observation, testing, and careful medication trials to understand what’s going on. Different types of pain respond to different medications, and one drug may help inflammatory pain but do little for nerve pain. Another may support joints but not muscle tension.

This is why pain-medication trials can be an important part of investigating behaviour, not something saved for last.

It’s similar to the difference between paracetamol and ibuprofen in people. Both are “painkillers”, but they work very differently. If one doesn’t help, it doesn’t mean there’s no pain — it may just mean it isn’t the right tool.

The same applies to dogs.

A Note on Anti-Anxiety Medication

For some dogs — particularly those whose nervous systems are so overwhelmed that they cannot take in new learning — it can be genuinely helpful to create enough safety for training to begin.

But without:

• a behaviour diary

• a clear training plan

• and an investigation into physical discomfort

Anti-anxiety medication alone often has little lasting impact.

This is why ruling out pain first matters so much.

Behaviour Is Communication

Dogs don’t tell us when something hurts. They show us.

Often long before there’s a limp. Often long before there’s a diagnosis.

Restlessness, reactivity, busyness, reduced tolerance — these are not failures. They are messages.

So before we label a dog as anxious, reactive, difficult, or poorly trained, ask:

Is it a behaviour issue — or a symptom?

Sometimes, the most compassionate and effective thing we can do is listen to the body first. Sandra Dlugabarskiene @ Lothian Dog Training