Chicken or the Egg: The Pain-Anxiety Relationship in Dogs

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The Complex Relationship Between Pain and Negative Emotional States/Behaviors in Dogs

If you have a dog with behavior issues—and if you happen to be working with Instinct or another reputable training company—your trainer or behavior consultant has likely already spoken with you about the importance of working with your veterinarian to rule out, or identify and address, any underlying pain issues.

That’s because pain is a very common factor in causing or exacerbating negative emotional states like fear, anxiety, and frustration (and the behavior issues associated with them) in both dogs and humans.

But when it comes to the relationship between pain and negative emotional states/behavior, it’s a two-way street—or perhaps, more accurately, an 8-lane roundabout with cars going in all directions.

In humans, current models designed to explain the connection between pain and emotions/behavior are based on “complex interactive or recursive processes” rather than simple cause-and-effect thinking (Lumley et al., 2011). Research shows that “depression is a predictor of persistent pain and pain is a predictor of the persistence of depression”; and “pain can cause feelings of anxiety, which in turn can make one more sensitive to pain.” (de Heer et al.,2014).

In dogs and a host of other species, “conditions such as pain induce a negative cognitive bias, which can be expected to exacerbate a wide range of problems associated with negative affective state, such as anxieties, fears, and frustrations. However, this relationship is probably bidirectional, with animals suffering from problems relating to the latter affective states also potentially more sensitive to pain.” (Mills et al., 2020)

In other words, pain is the proverbial chicken and fear/anxiety/aggression is the proverbial egg. Sometimes chickens lay eggs, and sometimes eggs hatch into chickens…who then lay eggs, who grow into chickens. You get the idea.

Today, we’re taking a closer look at how pain can manifest into emotional and behavior issues with our dogs, and vice versa. Then, we dive into what this all means, in the most practical sense, when it comes to protecting or improving our dogs’ behavioral health.

The Impact of Pain on Emotions & Behavior

Most of us are aware, through personal experience, that pain can have a significant effect on our mood—and in the case of chronic pain, on our ongoing emotional wellbeing.

Reams of research on human subjects support our anecdotal experiences. Pain commonly elicits negative emotional responses like sadness, frustration, and anger (Pasquale & Murphy, 2022); it raises emotional stress (Lumley et al., 2011); and it puts us at increased risk for mental health disorders, substance abuse, and more (Pasquale & Murphy, 2022). As many as 70% of individuals with anxiety and/or depressive disorders are also experiencing chronic pain (de Heer et al., 2014)

Just like with humans, pain in dogs appears to be a pervasive contributor to negative emotional states and behavior issues like fear, anxiety, reactivity and aggression.

A landmark 2020 study by Mills et al. suggests that anywhere from ~30-80% of cases referred to veterinary behaviorists for help with a behavior issue were experiencing some form of painful condition. (For what it’s worth, based purely on anecdotal experience, I’d place that number at the higher end of the range.)

But recognizing pain in dogs can be tricky. It doesn’t often show up in the ways we might expect. Many dogs who are in pain will still engage in behaviors like running, jumping, playing, and more. Many others will show no obvious, outward signs that they are experiencing discomfort.

Because of this, for many dogs whose fear, anxiety, or aggression is being caused or exacerbated by underlying pain, that pain goes undiagnosed and untreated.

Recognizing Pain in Dogs

While detecting obvious outward signs of pain won’t always be possible, there are lots of ways that our pain does “show up” in our dogs’ emotions and behavior.

In the aforementioned study by Mills et al. (2020), the authors outline some of the more commonly known ways that pain can impact behavior, as well as lesser known indicators that many dog owners, trainers, and even veterinarians often dismiss or overlook. Chances are, there are at least a few things on the list that will surprise you:

Emotional & Behavioral Indicators of Pain in Dogs (Mills et al., 2020):

• Snapping, biting or growling when handled
• Snapping, biting or growling if approached while resting
• Showing a general reluctance to move or a hesitancy to jump on/off objects
• Overt signs of lameness
• Difficulty learning or reluctance performing basic skills
• Decreased energy levels
• House soiling
• Attention-seeking behavior and ‘clinginess’
• “Compulsive” behaviors like fly snapping, excessive licking of surfaces, or licking/chewing at forelimbs, paws, or tail
• Pica (ingestion of non-food items)
• Destructiveness when left alone
• Fear/anxiety without an obvious cause
• Low frustration tolerance
• Resource guarding
• Refusal to go for a walk, braking on a walk, or hesitancy to walk on slick flooring
• Waking up at night

Noise sensitivity is another lesser known indicator of pain in dogs (Fagundes et al., 2018).

Pain may be the primary cause of the behavior issues outlined above, or its presence might be making an existing behavior issue worse. Either way, the presence of (potential or suspected) pain in dogs is not to be taken lightly.

Key Takeaway:
If left unmanaged, pain can not only make your dog a whole lot less happy and comfortable, it can make it difficult or impossible for you to achieve lasting, positive behavior change with your dog.

The Impact of Pain on Emotions & Behavior

Thanks to studies like the one highlighted above, dog professionals and owners alike are becoming more aware of the huge and pervasive role pain can often play in contributing to a dog’s fear, anxiety, aggression, or reactivity issues.

But, as we discussed in the intro to this newsletter, the relationship between pain and negative emotions is not a one-way street.

Emotional States Affect Pain Perception

Picture this: you’re walking from your kitchen to your living room and you stub your toe…really hard. Ouch! How do you react?

Chances are, that stubbed toe will feel a whole lot worse (and the pain will linger far longer) in scenario 1 than it will in scenario 2. It might be a silly example, but it illustrates an important reality:

A robust body of research shows that our brains process and perceive painful experiences very differently, depending on our emotional state (Wiech & Tracey, 2009):

Positive emotional states have been shown to inhibit pain perception (Zillmann et al., 1996; Weisenberg et al., 1998; Meagher et al., 2001), while negative emotional states can actually lead to or exacerbate pain (Rhudy and Meagher, 2000; Wunsch et al., 2003; Kenntner-Mabiala and Pauli, 2005).

In other words, when we—or our dogs—feel angry, frustrated, anxious, or fearful, our brains are more likely to interpret even mildly painful or uncomfortable stimuli as highly unpleasant.

But when we—or our dogs—feel happy, joyful, or relaxed, those same painful experiences are more likely to roll off our backs, going totally unnoticed or quickly dismissed as just a fleeting annoyance.

Chronic Negative Emotional States May Lead to or Exacerbate Chronic Pain

The relationship between emotional state and pain goes far beyond how a good or bad mood can impact our reaction to a stubbed toe.

Larson et al. (2004) and Carroll et al. (2004) found that (human) individuals suffering from depression are twice as likely to develop chronic musculoskeletal pain than non-depressed individuals. Roy-Byrne et al. (2008) suggest that, in injured workers, anxiety disorders actually preceded the onset of chronic pain.

It seems that chronic negative emotional states may actually leave people (and in all likelihood, dogs) more vulnerable to developing chronic pain conditions.

Key Takeaway:
The more we are able to help our dogs feel relaxed and happy throughout the day, and the more we can alleviate ongoing fear and anxiety, the less susceptible they may be to a) experience short-term negative impacts from painful or uncomfortable experiences, and b) develop longer term, chronic pain.

Chickens, Eggs, and Our Dogs’ Canine Behavioral Health

What does all of this mean for us and our dogs?

If your dog has a known or suspected painful condition, or if they are experiencing fear, anxiety, reactivity, etc., keep this in mind:

Where there are chickens, there are often eggs
…and where there are eggs, there are often chickens.

In other words, where there is pain, there is often fear, anxiety, or frustration; and where there is fear, anxiety or frustration, there is often (not always) underlying pain.

And so long as one of those two persist (either pain or negative emotional states), your dog may be at increased risk of experiencing both pain and negative emotional states (and the associated behavior issues) in the future.

Because of this, research suggests it is in your dog’s (and your) best interest to aggressively pursue interventions that target both potential pain and emotional wellbeing from the beginning.

Mills et al. (2020) state, “whenever there is a suspicion of pain involvement in a behavior case, treatment should consider the management of both pain and other negative affective states from the outset. This applies even if no overtly painful lesion can be found if we wish to safeguard the well-being of the patient.”

The authors go on to say, “it is our recommendation that it is better to treat suspected pain first rather than consider its significance only when the animal does not respond to behavior therapy.”

Tackling the Pain-Anxiety Connection: “All Paws on Deck”

Because of the complex, multidimensional relationship between pain and fear, anxiety, & frustration, it often pays to work with veterinary and behavior professionals who can help you and your dog navigate these muddy waters safely and efficiently.

Consulting with professionals may looks like:

• depending on your dog’s symptoms, asking your veterinarian for recommendations on diagnostic tests to identify potential sources of musculoskeletal pain, gastrointestinal discomfort, skin irritations/pain, etc.
• even in the absence of a specific diagnosis, working with your primary veterinarian or a veterinary behaviorist to determine whether pain management medications and/or behavior medications may be worth trialing
• consulting with veterinary professionals about whether interventions like acupuncture, hydrotherapy, diet changes, supplements, and so on could help make your dog more comfy and confident
• working with a behavior consultant on environmental adjustments like reducing exposure to stressors, adjusting routines, adding orthopedic beds, floor mats, etc. to your space, and so on
• working with a behavior consultant on a custom behavior therapy plan to help your dog feel more relaxed, confident, and happy as they move through the world

References:

Carroll, L.J., Cassidy, J.D., Cote, P., 2004. Depression as a risk factor for onset of an episode of troublesome neck and low back pain. Pain 107, 134–139.

de Heer EW, Gerrits MM, Beekman AT, Dekker J, van Marwijk HW, de Waal MW, Spinhoven P, Penninx BW, van der Feltz-Cornelis CM. The association of depression and anxiety with pain: a study from NESDA. PLoS One. 2014 Oct 15;9(10):e106907. doi: 10.1371/journal.pone.0106907. Erratum in: PLoS One. 2014;9(12):e115077. PMID: 25330004; PMCID: PMC4198088.

Fagundes A, Hewison L, McPeake K, Zulch H, Mills D. Noise Sensitivities in Dogs: An Exploration of Signs in Dogs with and without Musculoskeletal Pain Using Qualitative Content Analysis. Frontiers in Veterinary Science, 2018; 5 DOI: 10.3389/fvets.2018.00017

Kenntner-Mabiala, R., Pauli, P., 2005. Affective modulation of brain potentials to painful and nonpainful stimuli. Psychophysiology 42, 559–567.

Larson, S.L., Clark, M.R., Eaton, W.W., 2004. Depressive disorder as a long-term antecedent risk factor for incident back pain: a 13-year follow-up study from the Baltimore Epidemiological Catchment Area sample. Psychol. Med. 34, 211–219.

Lumley MA, Cohen JL, Borszcz GS, Cano A, Radcliffe AM, Porter LS, Schubiner H, Keefe FJ. Pain and emotion: a biopsychosocial review of recent research. J Clin Psychol. 2011 Sep;67(9):942-68. doi: 10.1002/jclp.20816. Epub 2011 Jun 6. PMID: 21647882; PMCID: PMC3152687.

Meagher, M.W., Arnau, R.C., Rhudy, J.L., 2001. Pain and emotion: effects of affective picture modulation. Psychosom. Med. 63, 79–90.

Mills DS, Demontigny-Bédard I, Gruen M, Klinck MP, McPeake KJ, Barcelos AM, Hewison L, Van Haevermaet H, Denenberg S, Hauser H, Koch C, Ballantyne K, Wilson C, Mathkari CV, Pounder J, Garcia E, Darder P, Fatjó J, Levine E. Pain and Problem Behavior in Cats and Dogs. Animals (Basel). 2020 Feb 18;10(2):318. doi: 10.3390/ani10020318. PMID: 32085528; PMCID: PMC7071134.

Pasquale, M., Murphy, N. (April 19, 2022). The Emotional Impact of the Pain Experience, Hospital for Special Surgery.

Rhudy, J.L., Meagher, M.W., 2000. Fear and anxiety: divergent effects on human pain thresholds. Pain 84, 65–75.

Roy-Byrne, P.P., Davidson, K.W., Kessler, R.C., Asmundson, G.J., Goodwin, R.D., Kubzansky, L., Lydiard, R.B., Massie, M.J., Katon, W., Laden, S.K., Stein, M.B., 2008. Anxiety disorders and comorbid medical illness. Gen. Hosp. Psychiatry 30, 208–225.

Wiech K, Tracey I. The influence of negative emotions on pain: behavioral effects and neural mechanisms. Neuroimage. 2009 Sep;47(3):987-94. doi: 10.1016/j.neuroimage.2009.05.059. Epub 2009 May 28. PMID: 19481610.

Weisenberg, M., Raz, T., Hener, T., 1998. The influence of film-induced mood on pain perception. Pain 76, 365–375.

Wunsch, A., Philippot, P., Plaghki, L., 2003. Affective associative learning modifies the sensory perception of nociceptive stimuli without participant’s awareness. Pain 102, 27–38.

Zillmann, D., de Wied, M., King-Jablonski, C., Jenzowsky, S., 1996. Drama-induced affect and pain sensitivity. Psychosom. Med. 58, 333–341.

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