Understanding pain and posttraumatic stress disorder comorbidity: Do pathological responses to trauma alter the perception of pain?

The relationship between traumatic exposure and pain perception in children: the moderating role of posttraumatic symptoms

ABSTRACT

Adverse childhood experiences (ACEs) affect approximately half of all children worldwide. These experiences have been linked to increased pain sensitivity in adulthood and a higher likelihood of developing severe chronic pain. However, most studies have assessed the effects of ACEs retrospectively, long after they occurred, leaving room for other factors to influence the observed outcomes. We investigated, for the first time, the association between ACEs and concurrent pain perception among young children who live in a conflict zone and are consistently exposed to potentially traumatic experiences. Participants were 60 elementary school children (ages 8-11 years) living in conflict regions (n = 39) or nonconflict regions (n = 21). Posttraumatic stress symptom (PTSS) severity, traumatic exposure, pressure pain threshold (PPT), and mechanical detection threshold (MDT) were measured. Trauma-exposed children had significantly lower PPT than did controls, but MDT was similar across groups. Pressure pain threshold correlated positively with proximity to the conflict zone and inversely with traumatic exposure magnitude and PTSS severity. In addition, PTSSs moderated the relationship between repeated traumatic exposure and PPT. Children with higher PTSS severity displayed pain hypersensitivity regardless of their traumatic exposure level, whereas in children with lower PTSS severity, greater traumatic exposure correlated with pain hypersensitivity. The results suggest that ACEs among children lead to concurrent pain hypersensitivity and distress and may put them at elevated risk of chronic pain early in life. In addition, our findings emphasize the need for identifying children with various PTSS levels to provide tailored interventions and mitigate the long-term negative effects of ACEs.

Traumatic Life Experience and Pain Sensitization: Meta-analysis of Laboratory Findings

OBJECTIVES

Psychological trauma often co-occurs with pain. This relationship has been explored using laboratory pain measures; however, findings have been mixed. Previous studies have limited operationalization of trauma (eg, posttraumatic stress disorder) or pain (eg, pain thresholds), which may contribute to conflicting results. Further, prior reviews likely underrepresent trauma experiences among people who are not receiving clinical care, limiting generalizability.

MATERIALS AND METHODS

We systematically reviewed the existing literature on the relationship between psychological trauma (eg, car accidents, sexual assault, childhood abuse, neglect) and laboratory pain (ie, quantitative sensory testing measures of pain threshold, intensity, summation, modulation), using inclusive criteria. The direction of the relationship between psychological trauma and pain sensitivity was evaluated, and moderation by purported pain mechanism (ie, pain detection, suprathreshold pain, central sensitization, inhibition) was explored.

RESULTS

Analyses were conducted using 48 studies that provided 147 effect sizes. A multivariate random-effects model with robust variance estimation resulted in a small but statistically significant overall effect size of g=0.24 (P=0.0002), reflecting a positive association between psychological trauma and enhanced laboratory pain sensitivity. Upon examination of mechanistic moderators, this relationship appears driven by effects on pain detection (g=0.28, P=0.002) and central sensitization (g=0.22, P=0.04). While effect sizes were similar across all moderators, effects on suprathreshold pain and inhibition were not statistically significant.

DISCUSSION

Findings demonstrate an overall pattern of trauma-related pain enhancement and point to central sensitization as a key underlying mechanism.

Psychosomatic Approach to Fibromyalgia Syndrome: Concept, Diagnosis and Treatment

Fibromyalgia syndrome (FMS) has chronic widespread pain (CWP) as a core symptom and a variety of associated somatic and psychological symptoms such as fatigue, sleep problems, cognitive disturbances, multiple somatic pain, and depression. FMS is the subject of considerable controversy in the realm of nosology, diagnosis, pathophysiology, and treatment.Moreover, the fact that FMS and mental illness are closely associated with each other might intensify the confusion for the distinction between FMS and mental disorders. This narrative literature review aims to provide the concept, diagnosis, and treatment of FMS from the integrative biopsychosocial and psychosomatic perspective. This article first explains the concepts of FMS as a disease entity of biopsychosocial model, and then summarizes the changes of diagnostic criteria over past three decades, differential diagnosis and comorbidity issue focused on mental illnesses. In addition, an overview of treatment of FMS is presented mainly by arranging the recommendations from the international guidelines which have been developed by four official academic associations.

Buprenorphine: prospective novel therapy for depression and PTSD

BACKGROUND

Depression and post-traumatic stress disorder (PTSD) are leading causes of disability and loss of life by suicide. Currently, there are less than satisfactory medical solutions to treat these mental disorders. Here, we explore recent preclinical and clinical studies demonstrating the potential of using buprenorphine to treat major depressive disorder, treatment-resistant depression, and PTSD.

METHOD

Bibliographic databases were searched to include preclinical and clinical studies demonstrating the therapeutic potential of buprenorphine and the involvement of the kappa opioid receptor (KOR) in mediating these effects.

RESULTS

Original clinical studies examining the effectiveness of buprenorphine to treat depression were mixed. The majority of participants in the PTSD studies were males and suffer from chronic pain and/or substance use disorders. Nonetheless, these recent studies and analyses established proof of concept warranting farther investigations. Additionally, KOR likely mediates the antidepressant and some of the anxiolytic effects of buprenorphine. Still, it appears that the full spectrum of buprenorphine's beneficial effects might be due to activity at other opioid receptors as well.

CONCLUSIONS

Pharmaceuticals' abilities to treat medical conditions directly relates to their ability to act upon the endogenous biological systems related to the conditions. Thus, these recent findings are likely a reflection of the central role that the endogenous opioid system has in these mental illnesses. Further studies are necessary to study the involvement of endogenous opioid systems, and specifically KOR, in mediating buprenorphine's beneficial effects and the ability to treat these medical conditions while minimizing risks for misuse and diversion.

Mutual maintenance of PTSD and physical symptoms for Veterans returning from deployment

Background: The mutual maintenance model proposes that post-traumatic stress disorder (PTSD) symptoms and chronic physical symptoms have a bi-directional temporal relationship. Despite widespread support for this model, there are relatively few empirical tests of the model and these have primarily examined patients with a traumatic physical injury. Objective: To extend the assessment of this model, we examined the temporal relationship between PTSD and physical symptoms for military personnel deployed to combat (i.e., facing the risk of death) who were not evacuated for traumatic injury. Methods: The current study used a prospective, longitudinal design to understand the cross-lagged relationships between PTSD and physical symptoms before, immediately after, 3 months after, and 1 year after combat deployment. Results: The cross-lagged results showed physical symptoms at every time point were consistently related to greater PTSD symptoms at the subsequent time point. PTSD symptoms were related to subsequent physical symptoms, but only at one time-point with immediate post-deployment PTSD symptoms related to physical symptoms at three months after deployment. Conclusion: The findings extend prior work by providing evidence that PTSD and physical symptoms may be mutually maintaining even when there is not a severe traumatic physical injury.

A cluster randomised, double-blind pilot and feasibility trial of an active behavioural physiotherapy intervention for acute whiplash-associated disorder (WAD)II

Whiplash-associated disorder (WAD) causes substantial social and economic burden, with ≥70% patients classified as WADII (neck complaint and musculoskeletal sign(s)). Effective management in the acute stage is required to prevent development of chronicity; an issue for 60% of patients. An Active Behavioural Physiotherapy Intervention (ABPI) was developed to address both physical and psychological components of WAD. The ABPI is a novel complex intervention designed through a rigorous sequential multiphase project to prevent transition of acute WAD to chronicity. An external pilot and feasibility cluster randomised double-blind (assessor, participants) parallel two-arm clinical trial was conducted in the UK private sector. The trial compared ABPI versus standard physiotherapy to evaluate trial procedures and feasibility of the ABPI for managing acute WADII in preparation for a future definitive trial. Six private physiotherapy clinics were recruited and cluster randomised using a computer-generated randomisation sequence. Twenty-eight (20 ABPI, 8 standard physiotherapy) participants [median age 38.00 (IQR = 21.50) years] were recruited. Data were analysed descriptively with a priori establishment of success criteria. Ninety-five percent of participants in the ABPI arm fully recovered (Neck Disability Index ≤4, compared to 17% in the standard physiotherapy arm); required fewer treatment sessions; and demonstrated greater improvement in all outcome measures (pain intensity, Cervical Range of Motion, Pressure Pain Threshold, EuroQol-5 Dimensions) except for the Impact of Events Scale and Fear Avoidance Beliefs Questionnaire. The findings support the potential value of the ABPI, and that an adequately powered definitive trial to evaluate effectiveness (clinical, cost) is feasible with minor modifications to procedures.

Reward and aversion processing in patients with post-traumatic stress disorder: functional neuroimaging with visual and thermal stimuli

In patients with post-traumatic stress disorder (PTSD), a decrease in the brain reward function was reported in behavioral- and in neuroimaging studies. While pathophysiological mechanisms underlying this response are unclear, there are several lines of evidence suggesting over-recruitment of the brain reward regions by aversive stimuli rendering them unavailable to respond to reward-related content. The purpose of this study was to juxtapose brain responses to functional neuroimaging probes that reliably produce rewarding and aversive experiences in PTSD subjects and in healthy controls. The stimuli used were pleasant, aversive and neutral images selected from the International Affective Picture System (IAPS) along with pain-inducing heat applied to the dorsum of the left hand; all were administered during 3 T functional magnetic resonance imaging. Analyses of IAPS responses for the pleasant images revealed significantly decreased subjective ratings and brain activations in PTSD subjects that included striatum and medial prefrontal-, parietal- and temporal cortices. For the aversive images, decreased activations were observed in the amygdala and in the thalamus. PTSD and healthy subjects provided similar subjective ratings of thermal sensory thresholds and each of the temperatures. When 46 °C (hot) and 42 °C (neutral) temperatures were contrasted, voxelwise between-group comparison revealed greater activations in the striatum, amygdala, hippocampus and medial prefrontal cortex in the PTSD subjects. These latter findings were for the most part mirrored by the 44 vs. 42 °C contrast. Our data suggest different brain alterations patterns in PTSD, namely relatively diminished corticolimbic response to pleasant and aversive psychosocial stimuli in the face of exaggerated response to heat-related pain. The present findings support the hypothesis that brain sensitization to pain in PTSD may interfere with the processing of psychosocial stimuli whether they are of rewarding or aversive valence.

The management of fibromyalgia from a psychosomatic perspective: an overview

Fibromyalgia (FM) is a central sensitization syndrome characterized by chronic widespread pain. FM is often comorbid with psychiatric disorders, as well as psychological distress that worsens the quality-of-life of people affected. The aim was to collect current evidence about the management of FM from a psychosomatic perspective. The literature was synthesized and summarized in a narrative format. The literature search was carried out in PubMed; review articles, meta-analysis, overview, and guidelines published in the last 10 years written in English were included. Five main topics (Diagnostic criteria of FM; Pathogenesis of chronic widespread pain in FM; Early stress and trauma as predisposing factors for central sensitization; FM and Psychiatric comorbidity; Implications for treatment) were pointed out and discussed. Much evidence underlies the importance of considering and treating the comorbidity of FM with psychiatric disorders and psychological factors that affect pain management. Validation of FM as a central sensitization syndrome by a clinician facilitates therapeutic strategies that involve patients as active participants in the pain management process, likely leading to improved outcomes.

When Emotional Pain Becomes Physical: Adverse Childhood Experiences, Pain, and the Role of Mood and Anxiety Disorders

OBJECTIVE

We examined the association between retrospective reports of adverse childhood experiences (ACEs) and painful medical conditions. We also examined the mediating and moderating roles of mood and anxiety disorders in the ACEs-painful medical conditions relationship.

METHOD

Ten-year longitudinal data were obtained from the National Comorbidity Surveys (NCS-1, NCS-2; N = 5001). The NCS-1 obtained reports of ACEs, current health conditions, current pain severity, and mood and anxiety disorders. The NCS-2 assessed for painful medical conditions (e.g., arthritis/rheumatism, chronic back/neck problems, severe headaches, other chronic pain).

RESULTS

Specific ACEs (e.g., verbal and sexual abuse, parental psychopathology, and early parental loss) were associated with the painful medical conditions. Baseline measures of depression, bipolar disorder, and posttraumatic stress disorder were also associated with the number of painful medical conditions. Anxiety and mood disorders were found to partially mediate the ACEs-painful medical conditions relationship. We determined through mediation analyses that ACEs were linked to an increase in anxiety and mood disorders, which, in turn, were associated with an increase in the number of painful medical conditions. We determined through moderation analyses that ACEs had an effect on increasing the painful medical conditions at both high and low levels of anxiety and mood disorders; though, surprisingly, the effect was greater among participants at lower levels of mood and anxiety disorders.

CONCLUSION

There are pernicious effects of ACEs across mental and physical domains. Dysregulation of the hypothalamic-pituitary-adrenal stress response and the theory of reserve capacity are reviewed to integrate our findings of the complex relationships.

Acute Whiplash Injury Study (AWIS): a protocol for a cluster randomised pilot and feasibility trial of an Active Behavioural Physiotherapy Intervention in an insurance private setting

INTRODUCTION

Whiplash-associated disorder (WAD) causes substantial social and economic burden internationally. Up to 60% of patients with WAD progress to chronicity. Research therefore needs to focus on effective management in the acute stage to prevent the development of chronicity. Approximately 93% of patients are classified as WADII (neck complaint and musculoskeletal sign(s)), and in the UK, most are managed in the private sector. In our recent systematic review, a combination of active and behavioural physiotherapy was identified as potentially effective in the acute stage. An Active Behavioural Physiotherapy Intervention (ABPI) was developed through combining empirical (modified Delphi study) and theoretical (social cognitive theory focusing on self-efficacy) evidence. This pilot and feasibility trial has been designed to inform the design of an adequately powered definitive randomised controlled trial.

METHODS AND ANALYSIS

Two parallel phases. (1) An external pilot and feasibility cluster randomised double-blind (assessor and participants), parallel two-arm (ABPI vs standard physiotherapy) clinical trial to evaluate procedures and feasibility. Six UK private physiotherapy clinics will be recruited and cluster randomised by a computer-generated randomisation sequence. Sixty participants (30 each arm) will be assessed at recruitment (baseline) and at 3 months postbaseline. The planned primary outcome measure is the neck disability index. (2) An embedded exploratory qualitative study using semistructured indepth interviews (n=3-4 physiotherapists) and a focus group (n=6-8 patients) and entailing the recruitment of purposive samples will explore perceptions of the ABPI. Quantitative data will be analysed descriptively. Qualitative data will be coded and analysed deductively (identify themes) and inductively (identify additional themes).

ETHICS AND DISSEMINATION

This trial is approved by the University of Birmingham Ethics Committee (ERN_15-0542).

TRIAL REGISTRATION NUMBER

ISRCTN84528320.

Co-occurring prescription opioid use problems and posttraumatic stress disorder symptom severity

BACKGROUND

Prescription opioids are the most rapidly growing category of abused substances, and result in significant morbidity, mortality and healthcare costs. Co-occurring with psychiatric disorders, persons with prescription opioid problems have negative treatment outcomes. Data are needed on the prevalence of co-occurring prescription opioid abuse and specific disorders, such as posttraumatic stress disorder (PTSD), to better inform clinical practice.

OBJECTIVE

To determine prevalence rates of current co-occurring prescription opioid use problems and PTSD symptom severity among patients in community addiction treatment settings.

METHODS

We abstracted administrative and chart information on 573 new admissions to three addictive treatment agencies during 2011. Systematic data were collected on PTSD symptoms, substance use, and patient demographics.

RESULTS

Prescription opioid use was significantly associated with co-occurring PTSD symptom severity (OR: 1.42, p < 0.05). Use of prescription opioids in combination with sedatives (OR: 3.81, p < 0.01) or cocaine (OR: 2.24, p < 0.001) also were associated with PTSD severity. The odds of having co-occurring PTSD symptoms and prescription opioid use problem were nearly three times greater among females versus males (OR: 2.63, p < 0.001). Younger patients (18-34 years old) also were at higher risk (OR: 1.86, p < 0.01).

CONCLUSIONS

Prescription opioid use problems are a risk factor for co-occurring PTSD symptom severity. Being female or younger increase the likelihood of this co-morbidity. Further research is needed to confirm these finding, particularly using more rigorous diagnostic procedures. These data suggest that patients with prescription opioid use problems should be carefully evaluated for PTSD symptoms.

Preventing the pain of PTSD

A selective opioid receptor agonist prevents fear memory consolidation in the amygdala in a mouse model of posttraumatic stress disorder (Andero et al.).

Neurobiology of stress-induced hyperalgesia

The intensity and severity of perceived pain does not correlate consistently with the degree of peripheral or central nervous system tissue damage or with the intensity of primary afferent or spinal nociceptive neurone activity. In this respect, the modulation of pain by emotion and context is now widely recognized. In particular, stress, fear and anxiety exert potent, but complex, modulatory influences on pain. Stress can either suppress pain (stress-induced analgesia) or exacerbate it (stress-induced hyperalgesia; SIH) depending on the nature, duration and intensity of the stressor. Herein, we review the methods and models used to study the phenomenon of SIH in rodents and humans and then present a detailed discussion of our current understanding of neural substrates and neurobiological mechanisms. The review provides perspectives and challenges for the current and future treatment of pain and the co-morbidity of pain with stress-related psychiatric disorders including anxiety and depression.

PTSD and depression as predictors of physical health-related quality of life in tobacco-dependent veterans

OBJECTIVE

Smoking, depression and PTSD are related to poor physical health outcomes and health-related quality of life (HRQoL). Previous studies examining the effects of quitting smoking on HRQoL have been mixed. This study aimed to examine the effects of PTSD, depressive symptoms and smoking cessation on HRQoL in a sample receiving treatment for PTSD.

METHOD

This study utilized archival interview and self-report data from a clinical trial (VA Cooperative Study 519) that recruited tobacco dependent veterans with chronic PTSD (N=943).

RESULTS

Analyses were conducted using hierarchical linear modeling and indicated that PTSD and depressive symptoms differentially affected the various physical health status domains. Additionally, quitting smoking was associated with better self-perceived health status and social functioning.

CONCLUSION

Our findings further explain the interrelationships of PTSD, depression, and smoking in the prediction of physical HRQoL and advocate the importance of integrated care.

Pain symptomatology and pain medication use in civilian PTSD

The comorbidity of pain syndromes and trauma-related syndromes has been shown to be high. However, there have been limited data, especially in civilian medical populations, on the role of trauma-related disorders such as posttraumatic stress disorder (PTSD) on chronic pain and pain medication use. We analyzed 647 general hospital patients in primary care and obstetrics and gynecological waiting rooms for the experience of trauma and PTSD-related stress disorders. PTSD symptoms were found to be significantly positively correlated with pain ratings (r=.282, P<0.001) and pain-related functional impairment (r=0.303, P<0.001). Those with a current PTSD diagnosis had significantly higher subjective pain and pain-related impairment ratings than those with no PTSD. Furthermore, those with a current diagnosis of PTSD were significantly more likely to have used opioid analgesics for pain control compared to those without a diagnosis of PTSD (χ(2)=8.98, P=0.011). When analyzing the separate PTSD symptom subclusters (re-experiencing, avoidance, and hyperarousal), all symptom clusters were significantly related to pain and pain-related impairment ratings, but only the avoidance cluster was significantly related to prior opioid pain medication use. We conclude that PTSD and trauma-related disorders are common in impoverished medical populations and that their presence should be examined in patients with pain syndromes. Furthermore, these data suggest that PTSD and pain may share a vulnerability pathway, including the endogenous opioid neurotransmission systems.

Anxiety sensitivity and pain-related anxiety in the prediction of fear responding to bodily sensations: A laboratory test

OBJECTIVE

The present investigation sought to examine the simultaneous effects of anxiety sensitivity and pain-related anxiety on fear and anxious responding to a 10% carbon dioxide enriched air challenge.

METHODS

Participants included 247 adults (53% women; mean age=21.91 years, S.D.=8.41) recruited from the community. At the laboratory, participants were administered a structured clinical interview, completed a battery of self-report measures, and underwent a 10% carbon dioxide enriched air challenge.

RESULTS

Both anxiety sensitivity and pain-related anxiety were significantly and uniquely predictive of post-challenge panic attacks, total post-challenge panic attack symptoms, and intensity of cognitive panic attack symptoms. Anxiety sensitivity, but not pain-related anxiety, also was predictive of post-challenge physical panic symptoms. The observed significant effects for both anxiety sensitivity and pain-related anxiety were evident above and beyond the variance accounted for by gender, age, current level of nonspecific bodily pain, and negative affectivity. Neither anxiety sensitivity nor pain-related anxiety was significantly predictive of change in anxiety focused on bodily sensations or heart rate.

CONCLUSION

Results suggest that anxiety sensitivity and pain-related anxiety, although related to one another, may be independently important variables underlying fear reactivity to bodily sensations.

Neuropathic pain in patients with upper-extremity nerve injury

PURPOSE

The purpose of this review was to present an analysis of the literature of the outcome studies reported in patients following traumatic upper-extremity (UE) nerve injuries (excluding amputation), to assess the presence of an association between neuropathic pain and outcome in patients following traumatic UE nerve injuries, and to provide recommendations for inclusion of more comprehensive outcome measures by clinicians who treat these patients.

SUMMARY OF KEY POINTS

A Medline and CINAHL literature search retrieved 48 articles. This review identified very few studies of patients with peripheral nerve injury that reported neuropathic pain. When pain was reported, visual analogue or numeric rating scales were most frequently used; standardized questionnaires measuring pain or psychosocial function were rarely administered. Recent evidence shows substantial long-term disability and pain in patients following peripheral nerve injury.

RECOMMENDATION

To better understand neuropathic pain in patients following peripheral nerve injury, future outcome studies should include valid, reliable measures of physical impairment, pain, disability, health-related quality of life, and psychosocial functioning.

The pain provocation technique for adolescents with chronic pain: preliminary evidence for its effectiveness

OBJECTIVE

This study aims to investigate the effectiveness of the "pain provocation technique" (PPT)--a focused treatment strategy incorporating interoceptive exposure (i.e., imagining increases in pain intensity), bilateral stimulation (tactile stimulation), and implementation of pain-related coping to decrease pain intensity--for adolescents suffering from chronic pain.

DESIGN

Prospective observational comparative study.

METHODS

Adolescents utilizing PPT (19 boys and 21 girls) within multimodal inpatient treatment were compared with adolescents in standard multimodal inpatient treatment matched for age, gender, and diagnosis. Core outcome variables (pain intensity, disability, emotional distress) were assessed at admission and 3 months posttreatment.

RESULTS

Adolescents in the PPT group demonstrated a sharper decrease in pain intensity and school aversion. Both groups demonstrated significant reductions in disability and emotional distress.

CONCLUSIONS

Results are discussed in terms of the importance of focused treatment strategies such as interoceptive exposure for adolescents suffering from disabling chronic pain. Future studies are warranted to carefully investigate the effectiveness and possible process of change during the PPT such as sensory, cognitive, emotional, and memory aspects.

Understanding the co-occurrence of anxiety disorders and chronic pain: state-of-the-art

The purpose of this article is to describe the current state-of-the-art regarding the co-occurrence of the anxiety disorders and chronic pain. First, we describe the core characteristics of chronic pain and its co-occurrence with the anxiety disorders. Second, we review data on the prevalence of co-occurrence. Third, we describe the mutual maintenance and shared vulnerability models, both of which have been offered to explain the co-occurrence of posttraumatic stress disorder (PTSD) and chronic pain and may have applicability to various other anxiety disorders. Fourth, we provide an integrative review of available research addressing the postulates of these models specific to the mechanisms of anxiety sensitivity, selective attention to threat, and reduced threshold for alarm. We conclude with general recommendations for improving assessment and treatment of patients who present with an anxiety disorder accompanied by clinically significant pain. Given that most of the available evidence has come from studies of PTSD and chronic pain, we provide a detailed agenda for future investigation of the co-occurrence of chronic pain and other anxiety disorders.

Pain, perceived injustice and the persistence of post-traumatic stress symptoms during the course of rehabilitation for whiplash injuries

The present study assessed the role of pain and pain-related psychological variables in the persistence of post-traumatic stress symptoms following whiplash injury. Individuals (N=112) with whiplash injuries who had been admitted to a standardized multidisciplinary rehabilitation program were asked to complete measures of pain, post-traumatic stress symptoms, physical function and pain-related psychological variables at three different points during their treatment program. The findings are consistent with previous research showing that indicators of injury severity such as pain, reduced function and disability, and scores on pain-related psychological were associated with more severe post-traumatic stress symptoms in individuals with whiplash injuries. Contrary to expectations, indicators of pain severity did not contribute to the persistence of post-traumatic stress symptoms. Univariate analyses revealed that self-reported disability, pain catastrophizing and perceived injustice were significant determinants of the persistence of post-traumatic stress symptoms. In multivariate analyses, only perceived injustice emerged as a unique predictor of the persistence of post-traumatic stress symptoms. The results suggest that early adequate management of pain symptoms and disability consequent to whiplash injury might reduce the severity of post-traumatic stress symptoms. The development of effective intervention techniques for targeting perceptions of injustice might be important for promoting recovery of post-traumatic stress symptoms consequent to whiplash injury.

Transition from acute to chronic postsurgical pain: risk factors and protective factors

Most patients who undergo surgery recover uneventfully and resume their normal daily activities within weeks. Nevertheless, chronic postsurgical pain develops in an alarming proportion of patients. The prevailing approach of focusing on established chronic pain implicitly assumes that information generated during the acute injury phase is not important to the subsequent development of chronic pain. However, a rarely appreciated fact is that every chronic pain was once acute. Here, we argue that a focus on the transition from acute to chronic pain may reveal important cues that will help us to predict who will go on to develop chronic pain and who will not. Unlike other injuries, surgery presents a unique set of circumstances in which the precise timing of the physical insult and ensuing pain are known in advance. This provides an opportunity, before surgery, to identify the risk factors and protective factors that predict the course of recovery. In this paper, the epidemiology of chronic postsurgical pain is reviewed. The surgical, psychosocial, socio-environmental and patient-related factors that appear to confer a greater risk of developing chronic postsurgical pain are described. The genetics of chronic postsurgical pain are discussed with emphasis on known polymorphisms in human genes associated with chronic pain, genetic studies of rodent models of pain involving surgical approaches, the importance of developing accurate human chronic postsurgical pain phenotypes and the expected gains for chronic postsurgical pain medicine in the post-genomic era. Evidence is then reviewed for a preventive multimodal analgesic approach to surgery. While there is some evidence that chronic postsurgical pain can be minimized or prevented by an analgesic approach involving aggressive perioperative multimodal treatment, other studies fail to show this benefit. The transition of acute postoperative pain to chronic postsurgical pain is a complex and poorly understood developmental process, involving biological, psychological and social-environmental factors.