9 Psychological Components of Whiplash-associated Disorder

Dr. Jeffrey Howard Ennis (1954–2019) was an internationally recognized psychiatrist and chronic pain specialist, an outdoor enthusiast, woodworker and artist. Dr. Ennis lived with chronic pain throughout his clinical life, and brought his personal insights into his clinical practice, leading by example. For a time he led the Chronic Pain Management Unit at Chedoke-McMaster Hospitals, and in 1998 he established the interdisciplinary Ennis Centre for Pain Management in Hamilton, Ontario. Jeff and his wife Gilda, who predeceased him, established the Ennis Endowment Fund for Pain Management, to be awarded to McMaster medical residents studying management of chronic pain. He is missed by both patients (who still ask) and colleagues who benefited from his insight and experience. 

The word whiplash, coined from whip and lash in 1928, pervades modern culture. Whiplash (WAD) is not just a physical disorder. It is associated with psychological consequences. In order to appreciate the burden of illness in WAD it is useful to know the prevalence of the most common psychiatric disorders affecting the general population. In Canada, 11% of men and 16% of women will develop a major depression in their lifetime,¹ while 9.2% of the Canadian population will develop post-traumatic stress disorder (PTSD) in their lifetime.² When looking at WAD, one study found that 58% of patients with chronic WAD symptoms went on to develop a psychiatric disorder within a one-year follow-up as compared to 29% of the WAD group who became physically asymptomatic.³ Epidemiologic data have shown anxiety to be present in 15.5% of the WAD population studied and mood disorder in 10.9% of the same patient group.⁴ In a detailed Canadian study that took place over one year, 48.3% of WAD subjects did not develop depressive symptoms at any point during the study, while 25.9% had initial depressive symptoms that resolved during the course of year; 10.0% had early depressive symptoms that resolved and then recurred at some point during follow-up; and 4.7% had early depressive symptoms that persisted throughout the follow-up period. Finally, 11.2% (n=385) had no depressive symptoms at baseline, but developed these at some point during the course of follow-up.⁵ The move from acute to chronic WAD symptoms after six months has been estimated to affect between 6% and 50% of patients. Among patients with chronic WAD, there is an increased risk of reporting somatic symptoms, beyond the typical symptoms of whiplash, as compared to patients who do not go on to have chronic symptoms.⁶ There is also evidence that some WAD patients can develop a somatoform disorder.

The burden of illness is significant. Does the pre-accident presence of mental health problems increase the risk of developing WAD? This question was studied by Wenzel et al.⁷ as part of the HUNT epidemiologic study in Norway. The authors found that impaired pre-accident health, whether from physical or psychological factors, increased the risk of developing WAD and neck pain.⁷ Identifying WAD patients at risk for developing a co-morbid psychiatric illness could potentially have clinical impact. These patients could receive early intervention. Therefore, it becomes important to identify pre-existing risk factors that increase the likelihood that a patient will develop a psychiatric disorder following the onset of WAD. Are their issues specific to the trauma of the accident or is it the WAD itself that also confers risk to the development of psychiatric illness?  

9.1 Psychological Risk Factors

There is a significant and somewhat varied body of evidence in regard to psychological risk factors post accident that are associated with chronic whiplash-associated neck pain. In 2008, Williamson et al.⁸ reviewed prospective cohort studies in which there were at least one baseline psychological variable and outcome measure related to ‘late-onset whiplash syndrome’.⁸ Overall, they concluded that the methodology was poor. There was considerable heterogeneity of outcome measures and as a result a meta-analysis could not be performed. Their primary findings were that the majority of evidence was inconclusive. There was limited evidence to support an association between lower self-efficacy and greater post-traumatic stress and late-onset whiplash syndrome. No association was found between late-onset symptoms and personality traits, general psychological distress, wellbeing, social support, life control, and psychosocial work factors.⁸ In 2009, Walton et al. identified a number of risk factors for persisting problems following whiplash injury. These factors included no post-secondary education, female sex (modest effect), not wearing a seat belt at the point of impact, a history of neck pain, a pain rating of greater than 55 out of 100, and high catastrophic thinking.⁹ However, by 2013, Walton had further refined the evidence.¹⁰ He and his colleagues conducted a rigorous overview of systematic reviews on the subject, identifying 13 papers that met their stringent inclusion criteria. This provided researchers with a large body of evidence to examine the question of risk factors. The purpose of this study was to identify consistent risk factors for delayed or non-recovery (i.e., chronic pain and/or disability) from neck pain. In looking at only psychological factors there is moderate confidence that early elevated post-traumatic stress symptoms at inception of neck pain and high catastrophic beliefs about pain are significant risk factors for poor outcome. All other factors, including anxiety, depression, personality traits, or coping behaviors proved inconclusive with low or very low confidence in their association with outcome. The authors recognized that the time at which coping was measured might alter outcome. Another predictor of interest is scoring on a pain scale. Such scales are not necessarily measuring pain only, but are also measuring suffering and therefore are measuring psychological factors. A score of greater than 5.5 out of 10 is associated with poor outcome. The Neck Disability Index also measures some psychological factors as it is a measure of the patient’s self perception of disablement. Scores above 15 (moderate perception of disability as a result of neck pain) is associated with poor outcome. Of interest, these authors did not find high or moderate confidence for the association between medical legal factors (compensation system, receiving compensation, lawyer involvement) and outcome. Finally, there are very little data on the impact of treatment on long-term outcome, whether it is physical or psychological treatment.¹⁰

The question of medical-legal factors and their impact on recovery in whiplash has been examined by other authors. Although Walton et al. did not find a significant association between medical-legal factors and outcome, it is recognized the whiplash has a very different outcome in different countries. There is a significant number of patients in North America with chronic whiplash. However, Lithuania and Greece have few while Germany had an epidemic of acute whiplash cases but still has a low incidence of chronic cases. In Lithuania and Greece, people do report neck pain after collisions. Two studies resulted in a 95% confidence interval with the true incidence of post-accident symptoms being 40% and 54%. However, none of the accident victims went on to develop chronic symptoms. In Greece, 91% of whiplash patients recover within four weeks and the rest within three months. Germany’s situation appears quite unique. From 1980 to 2000 there was a baffling epidemic of acute, not chronic, whiplash. The majority of claims were for three to four weeks of pain. Despite this, recovery was within approximately six weeks and even patients given collars for three weeks recovered within 12 weeks. Despite the wave of acute cases, the prognosis for recovery from whiplash in Germany remains good. In one cohort, 47% of accident victims had pain; however, this pain resolved within days. This suggests that the method by which a culture deals with neck injury can have a significant impact on outcome regardless of physical pathology.

It has been hypothesized that there are facets of the social order that bring about chronic whiplash. These are symptom expectation, symptom amplification, and symptom attribution, all psychological factors.¹¹

Correct answer: 3

9.2 Prognostic Factors  

Psychological variables can play a role in the outcome of treatment even before treatment is initiated. It is recognized that a patient’s self-perception of disability is critical to recovery. The longer an individual perceives themselves to be disabled, the less likely it is that they will return to work.¹² In one study, patients who were absent from work for more than six months showed the least amount of change in regard to their self perception of disability during treatment in a community-based psychosocial treatment program aimed at helping patients return to work. The corollary of this finding is that patients who believe they will recover, recover more quickly than those who do not.¹³

Over and above the physical impact of a whiplash, there are significant psychological sequelae of this disorder that require as much attention as does its physical impact. Importantly, there is evidence that a patient’s psychological response to whiplash is as physical as the physical components of their injury. The best way to understand this is to briefly review the neuroanatomy of pain, specifically the spinothalamic pathway. The neuroanatomy is complex and to try and reduce it to a few simple pathways does a great disservice to the subject. However, in order to help understand the connection between pain and the emotional response of patients, some of the pathways are worth understanding. There are two, somewhat more primitive aspects of the entire spinothalamic pain pathways that have direct connections to the limbic system of the brain. They are the paleospinothalamic tract and the archispinothalamic tract. The archispinothalamic tract is the oldest component of our pain pathways. It is part of the spinothalamic bundles that sends collateral fibers to the reticular formation, the periaqueductal grey matter, and the intralaminar nuclei of the thalamus. It also reaches the hypothalamus and the limbic system. It influences the autonomic, emotional, and behavioral response to pain. The paleospinothalamic tract is also a component of the spinothalamic tract. It sends fibers both ipsilateral and contralateral up the spinal cord, synapsing in the reticular formation, into the intralaminar thalamic nuclei and diffusely into the limbic system and cingulate gyrus, again influencing autonomic, emotional, and behavioral responses to pain. Our affective response to pain does have a hard-wired basis.

9.3 Psychological Treatment: Pharmacology

Turning our attention back to treatment, psychological factors are poor predictors of recovery, but they might have an impact on how a patient copes with whiplash.¹⁴ Treatment can be divided into two broad categories, pharmacological and nonpharmacological treatment strategies.

With respect to the pharmacological treatment of the psychological impact of whiplash, we will focus on the management of depression as this is a common psychological consequence of this disorder. Examining the treatment of every psychological consequence of WAD is beyond the scope of this chapter. What is important to recognize is that when present, depression is not simply an independent disorder of the whiplash injury. There are biological underpinnings linking depression and pain. Norepinephine (NE), serotonin (SE), substance P, and corticotropin-releasing factor have been implicated in the onset of depression and pain.¹⁵ It should not be surprising that patients with chronic pain are at high risk of developing a mood disorder. The severity of the mood disorder can have a negative impact on the prognosis of pain and function. Bair et al. noted this in a large cohort of primary care patients at three months.¹⁶ There is evidence that by treating the depression only, pain and function can improve.¹⁷

When treating patients with depression and co-morbid pain the focus is on finding antidepressants that have an impact on both problems. There is no literature in this area specific to whiplash. Rather, the literature focuses on depression and pain in general. From a treatment perspective, NE and SE are currently the primary focus of care when managing depression co-morbid with pain. Although all antidepressants have been demonstrated to have an impact on depression, not all of them have the same impact on pain. Pharmacologically, tricyclic antidepressants (TCAs), which affect a number of receptors including NE and SE when used to treat pain, have numbers needed to treat (NNT) for 50% effect of 1.4–2.6. In comparison, SE-specific medications such as fluoxetine, a serotonin reuptake inhibitor (SSRI), have NNT for 50% effect of 6.7.¹⁸ Although using antidepressants to treat pain even in patients without depression is effective, there is no clear evidence that the presence of depression and pain makes the treatment more effective.

The newer serotonin and norepinephrine reuptake inhibitors (SNRIs such as duloxetine and venlafaxine) have been demonstrated to be efficacious in the treatment of certain painful conditions such as fibromyalgia and diabetic neuropathy. NNT fall in the range of 4.5–5.7. Overall, TCAs appear to have better effect but they are not as well tolerated as SNRIs and many countries recommend SNRIs as first-line treatment for neuropathic pain.¹⁹

Correct answer: 4

9.4 Psychological Treatment: Multidisciplinary Care

Nonpharmacotherapy management of the psychological consequences of whiplash can be divided into two groups: multidisciplinary pain programs and individual psychotherapy. Teasell et al.²⁰ discovered while reviewing treatments for whiplash that interdisciplinary interventions may be more effective in reducing pain and sick leave than passive physiotherapy modalities, although more research is needed to determine which components of such interventions are beneficial. There is also some evidence that patients who receive interdisciplinary treatment earlier are more likely to return to work, but it is uncertain whether this simply reflects natural history or is a consequence of the intervention.2⁰ Few studies exist that are specific to whiplash. An earlier study by Provinciali et al. demonstrated the efficacy of ‘multimodal treatment’ for whiplash.²¹ Four years later Vendrig et al. used a multimodal treatment strategy, again demonstrating its effectiveness.²² The most recently published paper on the subject is from 2010. Once again, such treatment was found to have a positive impact on pain and function.²³ What can make these data somewhat confusing is that not all multidisciplinary pain programs are the same. As noted by Teasell et al., what remains unclear is exactly what component of the multidisciplinary treatment is resulting in a positive impact on the patient.²⁰

9.5 Psychological Treatment: Psychotherapy and Cognitive Behavioral Therapy

The final area under discussion is psychotherapy. This is a very large body of literature and for the sake of being able to address key points within the confines of this chapter, the primary focus will be on cognitive behavioral therapy (CBT). Although there are basic tenets that guide this treatment, as is true for multidisciplinary pain management programs, not all CBT is the same. There is a significant amount of literature demonstrating the efficacy of CBT in the management of chronic pain in general. It is considered a ‘gold standard’ of treatment for chronic pain. Evidence has shown that it can have an impact on pain, distress, pain interference with activities, and disability. This has been shown in systematic reviews and meta-analyses.²⁴ In regard to whiplash specifically, there is evidence that CBT can be an adjunct to the physical treatments of this disorder. This includes medication management, as well as interventional maneuvers such as infiltration or physiotherapy.²⁵ CBT has also been demonstrated to be helpful in treating patients with specific co-morbid psychiatric illness associated with whiplash. PTSD co-morbid with whiplash has been effectively treated using a trauma-oriented form of CBT in whiplash patients.²⁶ Finally, early intervention with CBT can reduce the likelihood of patients developing maladaptive behaviors associated with neck pain following a whiplash injury. By reducing catastrophic thinking, fear, and avoidance, and depressed and anxious mood, chronic whiplash can be prevented.²⁷ Whiplash is a complex disorder, resulting in both physical and psychological symptoms. It is not surprising that the cost of whiplash in Canada is estimated to be six hundred million, while in the United States it is 8.5 billion dollars.²⁸ The psychological impact of the disorder is significant, and when present can have a significant negative impact on prognosis. It is therefore important for clinicians to not only focus on the physical components of the disorder, but the psychological as well (Figure 9-1 and Figure 9-2). By treating both components of whiplash, the likelihood of improving a patient’s function and helping them return to their pre-injury activities is increased.

Correct answer: 1

9.6 References  

1. Health Canada. Mental Health – Depression. http://www.hc-sc.gc.ca/hl-vs/ iyh-vsv/diseases-maladies/depression-eng.php
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28. Whiplash Prevention Campaign. Whiplash Statistics. http:// www.whiplashprevention.org/Employers/WhiplashMatters/Pages/ Statistics.aspx
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