Chronic spinal pain and physical–mental comorbidity in the United States: results from the national comorbidity survey replication

Sex, gender, and pain: a review of recent clinical and experimental findings

Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed.

PERSPECTIVE

This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men.

Forebrain pain mechanisms

Emotional-affective and cognitive dimensions of pain are less well understood than nociceptive and nocifensive components, but the forebrain is believed to play an important role. Recent evidence suggests that subcortical and cortical brain areas outside the traditional pain processing network contribute critically to emotional-affective responses and cognitive deficits related to pain. These brain areas include different nuclei of the amygdala and certain prefrontal cortical areas. Their roles in various aspects of pain will be discussed. Biomarkers of cortical dysfunction are being identified that may evolve into therapeutic targets to modulate pain experience and improve pain-related cognitive impairment. Supporting data from preclinical studies in neuropathic pain models will be presented. Neuroimaging analysis provides evidence for plastic changes in the pain processing brain network. Results of clinical studies in neuropathic pain patients suggest that neuroimaging may help determine mechanisms of altered brain functions in pain as well as monitor the effects of pharmacologic interventions to optimize treatment in individual patients. Recent progress in the analysis of higher brain functions emphasizes the concept of pain as a multidimensional experience and the need for integrative approaches to determine the full spectrum of harmful or protective neurobiological changes in pain.

Outcomes and presurgery correlates of lumbar discectomy in Utah Workers' Compensation patients

BACKGROUND CONTEXT

Lumbar discectomy is the most common type of back surgery performed in the United States. Outcomes after this procedure can be variable and it appears that Workers' Compensation patients might be at increased risk for poor outcomes.

PURPOSE

To examine long-term multidimensional outcomes of lumbar discectomy within a cohort of Workers' Compensation patients from Utah and identify presurgical biopsychosocial factors related to poor outcomes.

STUDY DESIGN/SETTING

A retrospective cohort study consisting of a review of presurgical medical records and assessment of patient outcomes via a telephone survey. Outcomes were assessed at least 2 years postsurgery.

PATIENT SAMPLE

A consecutive sample of 271 workers from Utah who underwent lumbar discectomy from 1994 to 1999. A total of 134 patients were surveyed at the time of follow-up.

OUTCOME MEASURES

Patient satisfaction, Roland-Morris Disability Questionnaire, SF-36v2, and Stauffer-Coventry Index.

METHODS

A retrospective review of presurgical biopsychosocial variables and outcome assessment via telephone survey was conducted.

RESULTS

Work disability rate for the cohort was 12.7% (17/134). Analysis of patient satisfaction, back pain-related dysfunction, and the Short-Form Health Survey-36 subscales indicated approximately 25% of patients experienced poor outcomes. Older age, number of comorbid health conditions, assigned case manager, litigation, and time delay from injury to surgery were consistently statistically significant predictors (p<.05) of poor outcomes.

CONCLUSIONS

Results of this study suggest that compensated back surgery patients are at greater risk for poor lumbar discectomy outcomes than noncompensation patients. Presurgery correlates of poor outcomes may be useful in identifying high-risk compensation patients.

Depression and self-rated health are proximal predictors of episodes of sustained change in pain in independently living, community dwelling elders

OBJECTIVE

To identify, in community dwelling elders, the determinants of sustained pain improvement or worsening.

DESIGN

A longitudinal study with two baseline and 11 monthly follow-up interviews was conducted. Pain was assessed monthly using the Parmelee adaptation of the McGill Pain Inventory.

SUBJECTS

Subjects included 109 Caucasian and 132 African American, Philadelphia residing Medicare recipients (65-74 years of age).

OUTCOME MEASURES

To identify sustained pain change (> or =2 months), the data for each subject were reconfigured to yield 10 overlapping 3-month data segments. Each segment was classified as improved or worsened pain. Other variables included: the Geriatric Depression Scale (GDS), self-rated health (SRH), physical functioning, and number of improved or worsened medical conditions.

RESULTS

Pain experienced (over 3-month periods) was typically stable. Sustained improved pain was more likely than worsened pain. Odds ratios obtained through Generalized Estimation Equation analyses showed that a 1-point increase in GDS scores increased the odds of worsened pain by 1.18 (1.11-1.30). Fair/poor SRH, being female, and having medical conditions worsen increased the odds of worsened pain by 4.04 (2.12-7.70), 1.63 (1.11-2.38), and 2.12 (1.42-3.16), respectively. Observed, statistically significant associations between these variables, except gender, and improved pain were in the opposite direction.

CONCLUSIONS

With a 1-month time lag between predictor variable assessment and follow-up pain measures, the study supports temporal associations between depressive symptoms and SRH and subsequent pain change. Clinicians providing care to community dwelling elders are advised to evaluate and attend to both the depressive symptoms and SRH of their patients.

Interlocking oppressions: the effect of a comorbid physical disability on perceived stigma and discrimination among mental health consumers in Canada

People living with mental health problems often face stigma and discrimination; however, there is a lack of research that examines how comorbid conditions affect this perceived stigma. This study sought to determine whether people who have a comorbid physical and psychiatric disability experience more stigma than those with only a psychiatric disability. It also looked at how perceived stigma and discrimination affect physical and mental health. A secondary analysis on data from interviews with 336 former and current clients of the mental health system in a mid-size Canadian city in 2005 was performed. Of these, 203 (60.4%) reported they had a psychiatric disability, 112 (33.0%) reported that they had a physical disability, with 74 reporting both a psychiatric and a physical disability. People with a self-reported psychiatric disability and a self-reported comorbid physical disability faced more overall perceived discrimination/stigma (P = 0.04), than those with a psychiatric disability alone. Perceived discrimination/stigma was positively correlated with psychiatric problem severity (P = 0.02), and negatively correlated with self-rated general health (P < 0.001), physical condition (P < 0.001), emotional well-being (P < 0.001) and life satisfaction (P < 0.001). These results bring to light the aggravating effect of a physical disability on the perceived stigma for those living with a mental illness, and also strengthen the knowledge that stigma and discrimination have a negative impact on health. Healthcare providers should recognise this negative impact and screen for these comorbid conditions. Policy-makers should take measures such as improving access to housing and employment services to help reduce stigma and discrimination against this particularly vulnerable group.

Trends in long-term opioid therapy for noncancer pain among persons with a history of depression

OBJECTIVE

We report trends in long-term opioid use among patients with a history of depression from two large health plans.

METHODS

Using claims data, age- and gender-adjusted rates for long-term (>90 days) opioid use episodes were calculated for 1997-2005, comparing those with and without a depression diagnosis in the prior 2 years. Opioid use characteristics were calculated for those with a long-term episode in 2005.

RESULTS

Incident and prevalent long-term opioid use rates were three times higher in those with a history of depression. Prevalent long-term use per 1000 in patients with a history of depression increased from 69.8 to 125.9 at Group Health and from 84.3 to 117.5 at Kaiser Permanente of Northern California between 1997 and 2005. Those with a history of depression were more likely to receive a higher average daily dose, greater days supply, and Schedule II opioids than nondepressed persons.

CONCLUSION

Persons with a history of depression are more likely to receive long-term opioid therapy for noncancer pain than those without a history of depression. Results suggest that long-term opioid therapy for noncancer pain is being prescribed to a different population in clinical practice than the clinical trial populations where opioid efficacy has been established.

Suicidal thoughts and behavior among adults with self-reported pain conditions in the national comorbidity survey replication

We sought to examine whether the presence of a noncancer pain condition is independently associated with an increased risk for suicidal ideation, plan, or attempt after adjusting for sociodemographic and psychiatric risk factors for suicide and whether risk differs by specific type of pain. We analyzed data from the National Comorbidity Survey Replication, a household survey of U.S. civilian adults age 18 years and older (n = 5692 respondents). Pain conditions, nonpain medical conditions, and suicidal history were obtained by self-report. DSM-IV mood, anxiety, and substance use disorders were assessed using the World Health Organization's Composite International Diagnostic Interview. Antisocial and borderline personality traits were assessed with the International Personality Disorder Examination screening questionnaire. In unadjusted logistic regression analyses, the presence of any pain condition was associated with lifetime and 12-month suicidal ideation, plan, and attempt. After controlling for demographic, medical, and mental health covariates, the presence of any pain condition remained significantly associated with lifetime suicidal ideation (odds ratio, 1.4; 95% confidence interval, 1.1-1.8) and plan. Among pain subtypes, severe or frequent headaches and "other" chronic pain remained significantly associated with lifetime suicidal ideation and plan; "other" chronic pain was also associated with attempt.

PERSPECTIVE

The risk for suicidal thoughts and behaviors that may accompany back, neck, and joint pain can be accounted for by comorbid mental health disorders. There may be additional risk accompanying frequent headaches and "other" chronic pain that is secondary to psychosocial processes not captured by the mental disorders assessed.

New concept for backache: biopsychosocial pain syndrome

Recently a new concept for explaining backache, "biopsychosocial pain syndrome," has been suggested. Psychosocial factors play an important role in the development and persistence of backache from an early stage. Diagnosis and treatment of backache should be based on the new concept. A good relationship between doctors and patients influences treatment outcome and patient satisfaction. Treatment should be decided by patients themselves, after being informed of the natural history of the disease and the merit and demerit of the treatment.

Trends in use of opioids by noncancer pain type 2000-2005 among Arkansas Medicaid and HealthCore enrollees: results from the TROUP study

Use of prescription opioids for noncancer pain has increased significantly in recent years, but it is not known if trends differ among the most common noncancer pain conditions. We examined trends in opioid prescribing for the years 2000 through 2005 for individuals with arthritis/joint pain, back pain, neck pain, and headaches by type and number of pain diagnoses, using data from claims records from 2 health insurers: HealthCore commercially insured members (N = 3,768,223) and Arkansas Medicaid (N = 127,866). Rates of headache, back pain, and neck pain diagnoses increased significantly in Arkansas Medicaid enrollees but more modestly among HealthCore enrollees. Rates of opioid use increased in both groups, with long-term use (>90 days' supply per year) increasing at twice the rate of any use. Rates of opioid use did not differ widely between noncancer pain conditions, but long-term opioid use rates doubled with each additional pain diagnosis. Mean days supply and cumulative yearly dose increased between 2000 and 2005 for all pain types and with increasing number of pain diagnoses, but dose per day supply remained relatively stable. The greatest increases in dose among all the pain conditions were seen in short-acting DEA Schedule II opioids.

PERSPECTIVE

This study demonstrates increased use of opioids, particularly long-term use, in noncancer pain over a 6-year period among those with multiple pain types. These results appear to reflect a general increase in use of prescription opioids for noncancer pain rather than a condition-specific change in prescribing practices.

Pain and suicidal thoughts, plans and attempts in the United States

OBJECTIVE

This study examined the association between pain and suicidality in the general US population.

METHOD

Using data from the National Comorbidity Survey-Replication, we assessed relationships between four measures of pain (back and neck, headache, other nonarthritic pain and a summary score of the count of these conditions) and 12-month suicidal thoughts, plans and attempts using chi-square tests and logistic regression models. Multivariate logistic regression models controlled for demographic characteristics, chronic health conditions, mood, anxiety and substance use disorders.

RESULTS

In multivariate models adjusting for concurrent psychiatric disorders and other chronic medical conditions, suicidal ideation was associated with head pain (OR 1.9, 95% CI: 1.2, 3.0) and the pain summary score (OR 1.2, 95% CI: 1.0, 1.4). Suicide attempt was also associated with head pain (OR 2.3, 95% CI: 1.2, 4.4) and pain summary score (OR 1.7, 95% CI: 1.1, 2.6). Other nonarthritic pain was associated with suicide attempts (OR4.0, 95% CI: 1.8, 9.1).

CONCLUSIONS

These findings highlight the importance of pain as a potentially independent risk factor for suicide, particularly among those with head pain or multiple forms of co-occurring pain. Individuals suffering from chronic pain may be particularly appropriate for suicide screening and intervention efforts.

Chronic pain alters drug self-administration: implications for addiction and pain mechanisms

This review article focuses on the impact that the presence of pain has on drug self-administration in rodents, and the potential for using self-administration to study both addiction and pain, as well as their interaction. The literature on the effects of noxious input to the brain on both spinal and supraspinal neuronal activity is reviewed as well as the evidence that human and rodent neurobiology is affected similarly by noxious stimulation. The convergence of peripheral input to somatosensory systems with limbic forebrain structures is briefly discussed in the context of how the activity of one system may influence activity within the other system. Finally, the literature on how pain influences drug-seeking behaviors in rodents is reviewed, with a final discussion of how these techniques might be able to contribute to the development of novel analgesic treatments that minimize addiction and tolerance.

Employment outcomes of persons with a mental disorder and comorbid chronic pain

OBJECTIVE

This study examined the independent and interactive effects of common mental disorders and chronic pain conditions on employment and work outcomes among individuals under 65 years old.

METHODS

Cross-sectional data were analyzed from the second wave of Healthcare for Communities (HCC2), a household telephone survey of U.S. civilian adults conducted in 2000-2001 (N=5,328). Common mental disorders were assessed by using the short-form version of the World Health Organization's Composite International Diagnostic Interview. Chronic pain conditions and employment outcomes were identified by self-report. Logistic and linear regression analyses were used to provide estimates for work impairment on the basis of the presence of a mental disorder or a chronic pain condition or both.

RESULTS

The interaction between presence of a mental disorder and presence of a chronic pain condition was significantly associated with no work for pay in the past 12 months (odds ratio=2.3, 95% confidence interval=1.2-4.2) and number of days of work missed in the past month because of health (regression coefficient=1.47, SE=.59). In stratified analyses this effect persisted for women but not for men. The presence of a mental disorder and the presence of a chronic pain condition were each independently associated with limitations in work and any work missed in the past 30 days because of health, although the interaction was not significant.

CONCLUSIONS

Mental disorders and chronic pain are each associated with work disability. Mental disorders are more strongly associated with some work disability outcomes when they are accompanied by chronic pain, especially among women.

Comorbid painful physical symptoms and anxiety: prevalence, work loss and help-seeking

BACKGROUND

There is evidence that painful physical symptoms (PPS) are increased in patients with anxiety disorder (AD). This survey reports the 12-month prevalence and sociodemographic characteristics of PPS in subjects with and without AD, taking into account somatic comorbidity. In addition, the impact of PPS on work loss days (WLDs) and help-seeking was examined.

METHODS

In a cross-sectional, population-based study, a representative random sample of non-institutionalised adults from Belgium, France, Germany, Italy, The Netherlands and Spain (N=21,425) was interviewed using the World Mental Health Composite Diagnostic Interview (CIDI 3.0 of the WHO). 8296 respondents provided data on the occurrence of PPS, from which 5489 respondents reported the number of work loss days.

RESULTS

PPS were reported by 28% of respondents without AD and by 45% in those with AD. Female gender, higher age and lower educational level were predictive of PPS. No additive effect of AD and PPS was found on the WLD score, neither did the presence or not of a comorbid somatic disorder change the findings. Finally, respondents with both AD and PPS had numerically higher rates of help-seeking for emotional reasons (20.8% vs. 15.0% for respondents with AD but not PPS) and delayed their help-seeking for a numerically shorter period of time (289 vs. 413 days, respectively).

LIMITATIONS

The most important limitation of this study was its reliance on self-reported data about somatic disorders.

CONCLUSION

Approximately 45% of persons with anxiety disorder also reported the presence of PPS. No additive effect of AD and PPS was found on the WLD score, and the presence of PPS in AD does not delay help-seeking for emotional problems.

Employment outcomes of persons with a mental disorder and comorbid chronic pain

OBJECTIVE

This study examined the independent and interactive effects of common mental disorders and chronic pain conditions on employment and work outcomes among individuals under 65 years old.

METHODS

Cross-sectional data were analyzed from the second wave of Healthcare for Communities (HCC2), a household telephone survey of U.S. civilian adults conducted in 2000-2001 (N=5,328). Common mental disorders were assessed by using the short-form version of the World Health Organization's Composite International Diagnostic Interview. Chronic pain conditions and employment outcomes were identified by self-report. Logistic and linear regression analyses were used to provide estimates for work impairment on the basis of the presence of a mental disorder or a chronic pain condition or both.

RESULTS

The interaction between presence of a mental disorder and presence of a chronic pain condition was significantly associated with no work for pay in the past 12 months (odds ratio=2.3, 95% confidence interval=1.2-4.2) and number of days of work missed in the past month because of health (regression coefficient=1.47, SE=.59). In stratified analyses this effect persisted for women but not for men. The presence of a mental disorder and the presence of a chronic pain condition were each independently associated with limitations in work and any work missed in the past 30 days because of health, although the interaction was not significant.

CONCLUSIONS

Mental disorders and chronic pain are each associated with work disability. Mental disorders are more strongly associated with some work disability outcomes when they are accompanied by chronic pain, especially among women.

Comorbidity of pain and anxiety disorders

The comorbidity of anxiety disorders with pain has received little research attention even though recent studies show that these disorders are as likely to co-occur with chronic pain conditions as depressive disorder. Comorbid anxiety has implications for the impact and outcome of pain conditions. Even though it may be intuitively plausible to suppose that the anxiety occurs in the context of a preexisting pain condition, there is evidence for a reverse causal link and shared risk factors, including distal events occurring in childhood.

Psychosocial differences between high-risk acute vs. chronic low back pain patients

The present study was designed to evaluate the relative degree and type of emotional distress in high-risk acute low back pain (ALBP) subjects (defined as less than 3 months since initial injury) vs. high-risk chronic low back pain (CLBP) subjects (defined as greater than 3 months since initial injury). It is an extension of earlier findings that demonstrated the significant role that such emotional distress may play in the development of CLBP disability if not appropriately treated in the acute phase. This work stems from a conceptual three-stage model, which characterizes the progression from acute to chronic pain. Several psychosocial measures were administered that included information allowing for the classification of subjects as high-risk based upon an earlier developed screening algorithm. The ANCOVA procedure in SPSS was used to compare groups, controlling for gender, ethnicity, and age. Results revealed that CLBP subjects had higher rates of certain measures of emotional distress and depression relative to ALBP subjects. These findings further support the importance of effectively managing emotional distress factors early, when treating musculoskeletal disorders such as low back pain.

Anxiety disorders and comorbid medical illness

OBJECTIVE

To provide an overview of the role of anxiety disorders in medical illness.

METHOD

The Anxiety Disorders Association of America held a multidisciplinary conference from which conference leaders and speakers reviewed presentations and discussions, considered literature on prevalence, comorbidity, etiology and treatment, and made recommendations for research. Irritable bowel syndrome (IBS), asthma, cardiovascular disease (CVD), cancer and chronic pain were reviewed.

RESULTS

A substantial literature supports clinically important associations between psychiatric illness and chronic medical conditions. Most research focuses on depression, finding that depression can adversely affect self-care and increase the risk of incident medical illness, complications and mortality. Anxiety disorders are less well studied, but robust epidemiological and clinical evidence shows that anxiety disorders play an equally important role. Biological theories of the interactions between anxiety and IBS, CVD and chronic pain are presented. Available data suggest that anxiety disorders in medically ill patients should not be ignored and could be considered conjointly with depression when developing strategies for screening and intervention, particularly in primary care.

CONCLUSIONS

Emerging data offer a strong argument for the role of anxiety in medical illness and suggest that anxiety disorders rival depression in terms of risk, comorbidity and outcome. Research programs designed to advance our understanding of the impact of anxiety disorders on medical illness are needed to develop evidence-based approaches to improving patient care.

Neurovascular pains: implications of migraine for the oral and maxillofacial surgeon

Epidemiologic studies have shown that migraine headaches are a common finding in the general population, often associated with a high degree of disability. Additionally, migraine has a reported comorbidity with other medical conditions, most notably with chronic pains, such as temporomandibular disorders. The pathophysiologic mechanisms involved with migraine are suggestive of an increased and prolonged hyperexcitability to stimuli, especially within the trigeminal distribution. Because migraine is mediated by branches of the trigeminal nerve it has the potential to mimic other types of pains, such as toothache or sinusitis. It is therefore recommended that oral and maxillofacial surgeons be familiar with the diagnostic criteria for migraine headaches to identify and appropriately treat such individuals who present to their clinics.

Chronic physical conditions and use of health services among persons with mental disorders: results from the Israel National Health Survey

OBJECTIVE

This study aimed to determine the association between common mental disorders and common chronic physical conditions and the contribution of mental disorders to the likelihood of being a higher user of health services.

METHOD

A representative sample extracted from the National Population Register of noninstitutionalized residents of Israel aged 21 or older were interviewed at their homes between May 2003 and April 2004. Mental disorders were assessed using a revised version of the World Mental Health Composite International Diagnostic Interview. Chronic physical conditions were measured via a checklist of chronic physical disorders.

RESULTS

Current mood or anxiety disorders were found to be associated with higher likelihood of chronic pain, cardiovascular conditions, diabetes and respiratory conditions beyond the sociodemographic characteristics and the risk factors (BMI or smoking). Current mood or anxiety disorders increased the likelihood of being a higher user of primary care beyond the effects of gender, population group, self-evaluation of general health, chronic pain or chronic conditions.

CONCLUSION

The results regarding the prevalence of mental-physical comorbidity emphasize the need for integration in the physical and mental care of people with mental disorders.

Epidemiology of chronic pain with psychological comorbidity: prevalence, risk, course, and prognosis

OBJECTIVE

To review the relation between chronic pain and psychological comorbidities, and the influence on course and prognosis, based on epidemiologic and population studies.

METHOD

We present a narrative overview of studies dealing with the epidemiology of chronic pain associated with mental health and psychiatric factors. Studies were selected that were of good quality, preferably large studies, and those that dealt with prevalences, course and prognosis of chronic pain, risk factors predicting new pain and comorbid disorders, and factors that affect health outcomes.

RESULTS

Chronic pain is a prevalent condition, and psychological comorbidity is a frequent complication that significantly changes the prognosis and course of chronic pain. In follow-up studies, chronic pain significantly predicts onset of new depressions, and depression significantly predicts onset of new chronic pain and other medical complaints. Age, sex, severity of pain, psychosocial problems, unemployment, and compensation are mediating factors in course and prognosis.

CONCLUSION

In assessment of chronic pain, the evidence from epidemiologic studies makes it clear that chronic pain can best be understood in the context of psychosocial factors.

Mental health service use by older adults: the role of chronic pain

OBJECTIVE

Mental health disorders commonly co-occur in patients with chronic pain, but little is known about the role of chronic pain in mental health service use. In this study, the authors explored the role of chronic pain in mental health service use by adults according to age group.

METHOD

The authors conducted a cross-sectional analysis of survey data from the second wave of the Health Care for Communities telephone survey collected in 2000-2001. Participants consisted of U.S. civilian adults (N = 6629) from randomly selected U.S. households. Common mental disorders were assessed using the short-form versions of the World Health Organization's Composite International Diagnostic Interview. Chronic pain conditions and mental health services received were identified by self-report. Physical and mental functioning was assessed using the Short Form-12.

RESULTS

Adults older than age 60 had higher rates of chronic pain and lower rates of mental health service use compared with those aged 18-60 years. In multiple logistic regression models, an interaction effect was found between age and chronic pain (odds ratio: 3.0 [1.1-8.0]) with chronic pain significantly increasing the odds of any mental health care in the past year in adults older than 60 years of age.

CONCLUSIONS

Chronic pain increases the likelihood of mental health service use among older adults. Chronic pain may facilitate the presentation of distress in medical settings for these adults.

Antidepressants for the treatment of chronic pain

Chronic pain represents one of the most important public health problems and, in addition to classical analgesics, antidepressants are an essential part of the therapeutic strategy. This article reviews available evidence on the efficacy and safety of antidepressants in major chronic pain conditions; namely, neuropathic pain, headaches, low back pain, fibromyalgia, irritable bowel syndrome (IBS) and cancer pain. Studies, reviews and meta-analyses published from 1991 to March 2008 were retrieved through MEDLINE, PsycINFO and the Cochrane database using numerous key words for pain and antidepressants. In summary, evidence supports the use of tricyclic antidepressants in neuropathic pain, headaches, low back pain, fibromyalgia and IBS. The efficacy of the newer serotonin and norepinephrine reuptake inhibitors is less supported by evidence, but can be recommended in neuropathic pain, migraines and fibromyalgia. To date, evidence does not support an analgesic effect of serotonin reuptake inhibitors, but beneficial effects on well-being were reported in several chronic pain conditions. These results are discussed in the light of current insights in the neurobiology of pain, the reciprocal relationship between pain and depression, and future developments in this field of research.

Increased 12-month prevalence rates of mental disorders in patients with chronic somatic diseases

BACKGROUND

Although it is well established that chronic somatic diseases are significantly associated with a wide range of psychopathology, it remains unclear to what extent subjects with chronic somatic diseases are at increased risk of experiencing mental disorders. The present epidemiological study investigates age- and sex-adjusted 12-month prevalence rates of mental disorders in patients with cancer, and musculoskeletal, cardiovascular and respiratory tract diseases, based on comprehensive physicians' diagnoses and compared with physically healthy probands.

METHODS

Prevalence rates were calculated from two large epidemiological surveys. These studies investigated inpatients and patients from the general population with cancer (n = 174) and musculoskeletal (n = 1,416), cardiovascular (n = 915) and respiratory tract diseases (n = 453) as well as healthy controls (n = 1,083). The prevalence rates were based on the Munich Composite International Diagnostic Interview, a standardized interview for the assessment of mental disorders.

RESULTS

Prevalence rates were very similar for inpatients (43.7%) and patients from the general population (42.2%). The adjusted odds ratios (OR) of patients with chronic somatic diseases were significantly elevated for mental disorders in comparison with healthy probands (OR: 2.2). Mood, anxiety and somatoform disorders were most frequent. The prevalence rates did not differ significantly between the somatic index diseases. The number of somatic diseases per patient had a higher association with mental disorders.

CONCLUSIONS

There is a strong relationship between chronic somatic diseases and mental disorders. A future task is to improve the care of mental disorders in patients with chronic physical illness, specifically with multimorbid conditions.

Nitrous oxide (N2O) prevents latent pain sensitization and long-term anxiety-like behavior in pain and opioid-experienced rats

Improving rehabilitation after a severe tissue injury does not only require a reduction in pain, but also requires alleviation of negative affects, particularly anxiety. Although opioids remain unsurpassed analgesics to relieve moderate to severe pain, it has been shown that they also induce latent pain sensitization leading to long-lasting hyperalgesia via N-methyl-D-aspartate-(NMDA)-dependent pronociceptive systems. The present study evaluated the ability of nitrous oxide (N2O), a gas with NMDA antagonist properties, to prevent latent pain sensitization and long-term anxiety-like behavior (ALB) in rats with pain and opioid experiences. On D0, the pro-inflammatory drug carrageenan was injected in one hind paw of rats treated with fentanyl (4x100 microg/kg subcutaneously). Nociceptive threshold was evaluated with the paw pressure vocalization test. Rats were re-exposed to carrageenan or exposed to repeated non-nociceptive environmental stress (NNES) 2-3 weeks later. Rats were also challenged in the elevated plus-maze 2 weeks after fentanyl administration for evaluating ALB. The preventive effects of a single 4 h 50/50% N2O-O2 exposure performed on D0 was evaluated. Fifty percent N2O strongly reduced hyperalgesia induced by a first inflammation and its enhancement by fentanyl, and prevented exaggerated hyperalgesia induced by second inflammatory pain or NNES. Moreover, we provide first evidence that a high fentanyl dose induces long-term ALB 2 weeks after its administration. When associated with fentanyl, 50% N2O prevented such long-term ALB. These results suggest that a single exposure to N2O could improve post-injury pain management and facilitate rehabilitation especially when potent analgesics as opioids have to be used.

Back pain in relation to musculoskeletal disorders in the jaw-face: A matched case–control study

Back pain and temporomandibular disorders are both common conditions in the population with influence on the human motor system, but a possible co-morbidity between these conditions has not been fully investigated. The aim of this study was to test the hypothesis of an association between long-term back pain and pain and/or dysfunction in the jaw-face region. Back pain was defined as pain in the neck, shoulders and/or low back. The study-population comprised 96 cases with long-term back pain and 192 controls without back pain. We used a screening procedure, a questionnaire and a clinical examination of the jaw function. The questionnaire focused on location, frequency, duration, intensity and impact on daily life of symptoms in the jaw-face and back regions. The analysis was conducted on 16 strata, matched by age and sex for case vs. control, using Mantel-Haenszel estimates of matched odds ratio (OR) and 95% confidence interval (CI) as well as the corrected Mantel-Haenszel chi(2) test. The overall prevalence of frequent symptoms in the jaw-face region, as reported in the questionnaire, was 47% among cases and 12% among controls. The difference was statistically significant (P<0.0001) with a sevenfold odds ratio (CI: 3.9-13.7). Moderate to severe signs from the jaw region were clinically registered among 49% of the cases and 17% of the controls (P<0.0001, OR: 5.2, CI: 2.9-9.2). The results showed statistically significant associations between long-term back pain and musculoskeletal disorders in the jaw-face and indicate co-morbidity between these two conditions.

Comorbidity and impact of chronic spinal pain in Nigeria

STUDY DESIGN

A cross-sectional survey of households selected using multistage stratified sampling.

OBJECTIVE

This paper investigates the prevalence of chronic spinal pain, its profile of comorbidity, and its impact on role disability in Nigeria.

SUMMARY OF BACKGROUND DATA

Study was conducted in 21 states representing 57% of the national population. A probability sample (n = 2143) was interviewed.

METHODS

Self-reports of chronic spinal pain, other pain conditions, as well as comorbid medical conditions were obtained. Composite International Diagnostic Interview, version 3, was used to evaluate mood, anxiety, and substance use disorders. Functional role impairment was assessed with questions about days out of role.

RESULTS

Chronic spinal pain was present in 16.4% (95% confidence interval, 14.5%-18.5%) of the sample. Prevalence increased with age of respondents, with 1 in 3 persons 60 years of age and older reporting chronic spinal pain. Persons with chronic spinal pain were at elevated risk to have chronic pain at other anatomic sites, to have a range of medical comorbidities, and to have mood and substance use disorders. Even though about one third of the decrement in functional role performance associated with chronic pain condition was attributable to demographics and comorbid conditions, chronic spinal pain was independently associated with significant role impairment.

CONCLUSION

Chronic spinal pain is a common problem in the Nigerian community, and persons 60 years of age and older may be at particularly elevated risk. Chronic spinal pain is associated with increased probability of comorbid physical and mental disorders. These comorbid conditions partly but do not fully explain the disability associated with chronic spinal pain, which therefore constitutes a substantial health burden on the society.

Chronic pain management in spine disorders

Chronic nonmalignant pain is less a symptom of a disease than a disease in itself. Accordingly, successful treatments rely less on identifying underlying pathology than on treating neural causes of pain amplification, psychologic causes of disability, and the sequelae of deconditioning and psychiatric illness. The outcome, when such treatment is provided, is remarkably favorable.

Frequency and priority of pain patients' health care use

BACKGROUND

Increased health care use by pain patients is largely due to conditions other than their identified pain condition, but the kinds of services accounting for increased service use are poorly understood. This study assesses reasons for health care visits of pain patients versus controls, and compares characteristics of pain patients who differ in frequency and priority of service use.

METHODS

The study samples included consecutive, primary care back pain (N=807), headache (N=831), and temporomandibular disorder pain (N=372) patients who were interviewed by telephone. Subsequently, age-sex matched controls with a primary care visit in the 6 months before the matched case's pain visit were identified. Over the following 3 years, diagnostic codes for health care visits were classified based on the Oregon Prioritized List of Health Services and case-control differences in major classes of care were compared. Pain patients differing in frequency and priority of service use were compared on measures of pain severity, chronicity, and psychosocial dysfunction.

RESULTS

Pain patients' increased health care use was sustained over 3 years. Increased utilization was largely due to symptomatic and ill-defined conditions, lower priority chronic disease, lower and higher priority acute disease, and mental health care. About one-half of the pain patients (vs. one-third of the controls) were frequent health care users. About one-third of the pain patients (vs. one-sixth of the controls) were frequent users who predominantly used medical care for lower priority conditions, and this difference accounted for most of the case-control difference in the prevalence of high users. Pain patients with frequent health care use had more severe pain and greater psychosocial dysfunction than pain patients with less frequent health care use. Among frequent users, pain patients who predominantly used services for lower priority conditions did not differ on measures of pain severity, chronicity, or somatization when compared with frequent users who typically used services for higher priority conditions.

CONCLUSIONS

The kind of problems explaining heightened service use of pain patients is more varied and complex than previously understood. These results call for increased attention to the implications of health care providers responding to presenting complaints as if each were a unique problem, without bringing continuity or an integrating perspective to patients' overall experience and management of illness.

Cognitive activation theory of stress, sensitization, and common health complaints

According to the cognitive activation theory of stress (CATS), a formal system of systematic definitions, the term "stress" is used for stress stimuli, the stress experience, the nonspecific, general stress response, and the experience of the stress response. The stress response is normal, healthy, and necessary alarm. If sustained there may be a risk of illness and disease. The level and duration of the alarm depend on the expectancy of the outcome of stimuli and the specific responses available for coping. The most common health complaints are subjective health complaints like muscle pain, tiredness and mood changes. These are normal aches of short duration and low intensity for most people. For some the pains and complaints are substantial and longlasting with serious implications for functioning. There are no sharp or obvious limits in the distribution of health complaints, separating "normal" and endurable pain and complaints, and intolerable complaints that need professional help. These conditions are most often unspecific, and are the most common reason for encounters with health professionals, and the most frequent reason for sick leave and disability. There is a striking comorbidity for all these conditions. This may be explained by psychobiological sensitization within neural loops, maintained by sustained activation, which has been suggested as a mechanism for these conditions.

The relation between multiple pains and mental disorders: results from the World Mental Health Surveys

It is unclear whether differences exist in the prevalence of mood, anxiety and alcohol use disorders among persons with multiple pain conditions compared with those with single pain problems. We conducted population surveys in 17 countries in Europe, the Americas, the Middle East, Africa, Asia, and the South Pacific. Participants were community-dwelling adults (N=85,088). Mental disorders were assessed with the Composite International Diagnostic Interview. Pain was assessed by self-report. Both multiple and single site pain problems were associated with mood and anxiety disorders, but not with alcohol abuse or dependence. In general, the prevalence of specific mood and anxiety disorders followed a linear pattern with the lowest rates found among persons with no pain, intermediate rates among those with one pain, and highest rates among those with multi-site pain problems. Relative to persons not reporting pain, the pooled estimates of the age-sex adjusted odds ratios were 1.8 (1.7-2.0) for mood disorders and 1.9 (1.8-2.1) for anxiety disorders for persons with single site pain; 3.7 (3.3-4.1) for mood disorders and 3.6 (3.3-4.0) for anxiety disorders among those with multi-site pain. Our results indicate that the presence of multiple pain conditions was strongly and comparably associated with mood and anxiety disorders in diverse cultures. This consistent pattern of associations suggests that diffuse pain and psychiatric disorders are generally associated, rather than diffuse pain representing an idiom for expressing distress that is specific to particular cultural settings or diffuse pain solely representing a form of masked depression.

Stress-related musculoskeletal pain

While stress is often considered by patients and clinicians alike as an important factor in the onset and maintenance of widespread musculoskeletal pain, the relationship is more complex than appears on initial consideration. The types of event that lead to stress need description, and the role of traumatic events are particularly important because of the shared association with post-traumatic stress disorder. The substantial overlap with psychiatric disorders and the role of stress in their aetiology must be assessed in patients. The lack of specificity of the symptoms of the different disorders used to describe widespread musculoskeletal pain may be explained by their shared aetiology, including neural sensitization and alterations of the hypothalamic-pituitary-adrenal (HPA) axis due to stress. Fear avoidance is a central stress-related perceptual characteristic and behavioural dimension in these disorders. Treatment depends on thorough assessment, including psychiatric diagnosis, avoiding simplistic attributions and implementing evidence-based treatments that are well documented.

The effect of age on the onset of pain interference in a general population of older adults: prospective findings from the North Staffordshire Osteoarthritis Project (NorStOP)

Pain that interferes with daily life appears to be strongly age-related in cross-sectional studies, although the nature of this relationship over time has not been established. We have investigated the onset and persistence of pain and pain interference over a 3-year period to determine their association with age in older people. A 3-year follow-up postal survey was conducted of adults aged 50 years and over (n=5366) who had previously been recruited as part of the North Staffordshire Osteoarthritis Project. Four thousand two-hundred and thirty-four completed questionnaires were received (adjusted response 84.7%). The occurrence of pain interference at 3 years was 19.7% in persons free of such pain at baseline, higher in females than males (6.0% difference; 95% CI: 2.6%, 9.3%), and showed a clear age-related trend with a more than twofold increase from 50 to 59 years (16.0%) to the 80+ years (35%). Any pain at follow-up was reported by 48% of those pain-free at recruitment, and this figure was similar for males and females, and across 10-year age-groups. Persistence of pain interference (72.1%) at 3 years was high. In adults aged 50 years and over, the onset of pain that interferes with life shows a clear gender difference and a consistent rise with age into the oldest age-group. This was in strong contrast to the onset of pain which showed no gender or age-related trends. The implications for public health, as for the treatment of the individual, are twofold, relating to efforts to prevent disabling pain from occurring and to understand the factors that accelerate the impact which pain has on everyday life when people reach the oldest ages.

Mental disorders among persons with chronic back or neck pain: results from the World Mental Health Surveys

This paper reports cross-national data concerning back or neck pain comorbidity with mental disorders. We assessed (a) the prevalence of chronic back/neck pain, (b) the prevalence of mental disorders among people with chronic back/neck pain, (c) which mental disorder had strongest associations with chronic back/neck pain, and (d) whether these associations are consistent across countries. Population surveys of community-dwelling adults were carried out in 17 countries in Europe, the Americas, the Middle East, Africa, Asia, and the South Pacific (N=85,088). Mental disorders were assessed with the Composite International Diagnostic Interview, third version (CIDI 3.0): anxiety disorders (generalized anxiety disorder, panic disorder/agoraphobia, posttraumatic stress disorder, and social anxiety disorder), mood disorders (major depression and dysthymia), and alcohol abuse or dependence. Back/neck pain was ascertained by self-report. Between 10% and 42% reported chronic back/neck pain in the previous 12 months. After adjusting for age and sex, mental disorders were more common among persons with back/neck pain than among persons without. The pooled odds ratios were 2.3 [95% CI=2.1-2.5] for mood disorders, 2.2 [95% CI=2.1-2.4] for anxiety disorders, and 1.6 [95% CI=1.4-1.9] for alcohol abuse/dependence in people with versus without chronic back/neck pain. Although prevalence rates of back/neck pain were generally lower than in previous reports, mental disorders were associated with chronic back/neck pain. The strength of association was stronger for mood and anxiety disorders than for alcohol abuse/dependence. The association of mental disorders with back/neck pain showed a consistent pattern across both developed and developing countries.

Mental disorders in patients with obesity in comparison with healthy probands

OBJECTIVE

Findings concerning the association of obesity and mental disorders are inconsistent. The present epidemiological study investigates adjusted 4-week, 12-month, and lifetime prevalence rates of mental disorders in obese individuals compared with physically healthy probands and overweight individuals. Correlates of the associations are examined.

METHODS

Prevalence rates were calculated from two large epidemiological surveys from both the general population of Germany and inpatient centers. The surveys investigated subjects with obesity (n=910) and overweight (n=1550), as well as physically healthy probands (n=495). The prevalence rates were based on the Munich-composite international diagnostic interview, a standardized interview for the assessment of mental disorders. Correlates of mental disorders in obese individuals were assessed using self-report questionnaires and medical examinations.

RESULTS

The adjusted odds ratios (OR) of obese inpatients and obese patients from the general population were significantly elevated in comparison with healthy probands for the 4-week (OR: 2.2; 2.3), 12-month (OR: 1.8; 2.7) and lifetime (OR: 1.4; 2.0) periods. Prevalence rates of overweight individuals were below those of obese individuals. Mood, anxiety and somatoform disorders were most frequent. In particular, sex, marital status and comorbid musculoskeletal diseases proved to be correlates of an increased risk for mental disorders in obese individuals. The presence of comorbid mental disorders was associated with significantly increased health care use and lower quality of life.

CONCLUSIONS

There is a strong relationship between obesity and mental disorders. A future task is to improve care of mental disorders in patients with obesity.

The comorbidity of headache with other pain syndromes

In this article, we consider the possible reasons and supporting evidence for the comorbidity of chronic pain conditions. To simplify the discussion, we primarily focus on the epidemiology of headache with other pain conditions, dividing studies into those based on children or adolescents and those based on adults. We consider exogenous and endogenous factors, and methodological challenges, in understanding whether and how 2 pain conditions may be related.

The World Health Organization World Mental Health Survey Initiative

To present an overview of the World Health Organization World Mental Health (WMH) Survey Initiative. The discussion draws on knowledge gleaned from the authors' participation as principals in WMH. WMH has carried out community epidemiological surveys in more than two dozen countries with more than 200,000 completed interviews. Additional surveys are in progress. Clinical reappraisal studies embedded in WMH surveys have been used to develop imputation rules to adjust prevalence estimates for within- and between-country variation in accuracy. WMH interviews include detailed information about sub-threshold manifestations to address the problem of rigid categorical diagnoses not applying equally to all countries. Investigations are now underway of targeted substantive issues. Despite inevitable limitations imposed by existing diagnostic systems and variable expertise in participating countries, WMH has produced an unprecedented amount of high-quality data on the general population cross-national epidemiology of mental disorders. WMH collaborators are in thoughtful and subtle investigations of cross-national variation in validity of diagnostic assessments and a wide range of important substantive topics. Recognizing that WMH is not definitive, finally, insights from this round of surveys are being used to carry out methodological studies aimed at improving the quality of future investigations.

Narcotic drug use among patients with lower back pain in employer health plans: a retrospective analysis of risk factors and health care services

OBJECTIVE

This study examines the risk factors of narcotic drug use, medical and pharmacy claim costs, and health services use among lower back pain (LBP) patients who use narcotic medications.

METHODS

This retrospective study used administrative claims data between September 2002 and March 2004 from 3 employer health plans that collectively contained records of 165,569 employees 18 to 64 years of age. Multivariate regression analyses were performed to examine risk factors and health care services use consequences of narcotic drug use in patients with LBP.

RESULTS

The study sample included 13,760 patients with LBP due to mechanical causes. Nearly 60% were female and the average age was 47 years. Almost half of the patients with LBP (45%) used narcotic drugs. Narcotic-using patients with LBP had significantly higher rates of comorbid conditions than patients with LBP not using narcotic drugs; hypertension (23% vs 13%), arthritis (14% vs 4%), depression (10% vs 5%), anxiety (6% vs 3%), and cancer (2% vs 1%) (P<0.001). Patients with LBP with 2 identified psychological comorbid conditions, depression and anxiety, on average used more narcotic medications. Patients with LBP who had surgery were significantly more likely to use narcotic drugs within 1 week of procedure than those patients without surgery (P<0.001). In contrast, patients with LBP who had chiropractic services for LBP were less likely to take narcotic drugs within 7 days after services compared to those without chiropractic services (P<0.001). Furthermore, controlling for health conditions, patients with LBP who took narcotic medications were significantly more likely than patients not taking narcotics to have an emergency room visit within 30 days after the initial narcotic drug prescription dates (P<0.001). Narcotic-using patients with LBP accounted for 62% of health care costs among all patients with LBP. The average monthly health care cost for a narcotic-using LBP patient was $1222, compared to $430 for a LBP patient not using narcotic drugs (P<0.001).

CONCLUSIONS

The subjects with LBP who used narcotic medications were more likely to have additional coexisting health conditions and used more health care services than nonusing patients with LBP (P<0.001). Unadjusted health care services costs, including pharmacy claims costs, were significantly higher in patients with LBP using narcotic drugs than in nonusing patients with LBP (P<0.001).

Psychiatric aspects of pain

PURPOSE OF REVIEW

Pain is a common reason for seeking healthcare. Chronic pain is commonly comorbid with psychiatric disorders. New evidence provides fresh insights into the nature of the link between pain and mental disorders and offers opportunity to refine treatment approaches.

RECENT FINDINGS

Even though depression is the most commonly studied comorbid psychiatric disorder, new studies show that other mental disorder, especially anxiety disorders, are also common. Comorbid conditions, including other chronic physical conditions, account for a substantial proportion of the disability associated with chronic pain conditions. The causal link between chronic pain and mental disorders may vary depending on the specific mental disorder, but the link may be mediated by biological, psychological, and social factors. Recent findings also suggest that the evolution of the comorbidity may differ between the sexes. Promising interventions for chronic pain that also target contextual psychosocial problems have been recently described.

SUMMARY

The frequent occurrence of mental disorders among patients with pain, especially those whose pain is chronic, has implications for the management of such patients. Current understanding of the complexity of this link not only provides opportunities for designing appropriate interventions but also raises new questions for further research.

Körperliche Beschwerden bei Patienten mit psychischen Störungen

Zusammenfassung. Die Literatur bietet bislang nur wenige Systematisierungshilfen und Handlungshinweise in Bezug auf die Bedeutung und psychotherapeutische Behandlungsimplikationen somatischer Beschwerden bei psychischen Störungen. Die vorliegende Übersichtsarbeit hat zum Ziel, diese Lücke zu schließen. Es erfolgt eine Systematisierung somatischer Beschwerden auf der Basis möglicher pathogenetischer Zusammenhänge zu psychischen Störungen. Basierend auf dieser Unterteilung werden daraus ableitbare Besonderheiten psychotherapeutischer Interventionen diskutiert. Die Systematisierung umfasst somatische Beschwerden, die 1) vorwiegend körperlicher Ursache und 2) Teil einer psychischen Störung sein können. Im ersten Fall erfolgt eine weitere Unterteilung der somatischen Beschwerden auf der Basis ihres kausalen Zusammenhangs mit der psychischen Störung (ursächlich für, Folge von und zufällig koexistent). Bei somatischen Beschwerden, die Teil einer psychischen Störung sind, werden insbesondere pathogenetische und behandlungsrelevante Aspekte somatoformer Störungen diskutiert. Die Übersichtsarbeit verdeutlicht die pathogenetische Vielfalt somatischer Beschwerden bei Patienten mit psychischen Störungen und unterstreicht die Bedeutung krankheitsspezifischen Wissens sowie eines interdisziplinär arbeitenden Versorgungsnetzes bei Patienten mit psychischer und somatischer Symptomatik.

Does minor trauma cause serious low back illness?

STUDY DESIGN

Prospective, 5-year, cohort study of working subjects.

OBJECTIVES

To assess whether the occurrence of common minor trauma events affects the risk of developing serious low back pain (LBP) and LBP disability in subjects with and without degenerative changes to the lumbar spine.

SUMMARY OF BACKGROUND DATA

Although some theories suggest that minor traumatic events in combination with preexisting degenerative changes commonly cause significant structural injury to spinal segments and serious LBP illness, no prospective data exist on the relationship of minor trauma, detailed structural changes, and outcome measures of serious LBP episodes and occupational disability.

METHODS

Two hundred subjects without clinical LBP problems were recruited, and underwent baseline clinical and imaging studies. Every 6 months, subjects completed a scripted, algorithm-based interview assessing interval back pain episodes, severity, medical treatment, occupational disability, and the subject's perceived relation of this LBP episode to any preceding event. If a serious LBP episode clinically required a new magnetic resonance examination, the follow-up imaging was obtained and compared to baseline for interval changes.

RESULTS

There was no association of minor trauma to adverse LBP events. For each 6-month study interval, the risk of developing a serious LBP episode was 2.1% unassociated with minor trauma and 2.4% following minor trauma (P = 0.59). Neither the frequency of minor trauma events nor the reported severity of the event correlated with adverse outcomes. Subjects with advanced structural findings were not more likely to become symptomatic with minor trauma events than with spontaneously evolving LBP episodes. Follow-up magnetic resonance imaging evaluating new serious LBP illness rarely revealed new clinically significant findings. Age and sex-adjusted prediction models, including abnormal psychometric testing, smoking, and compensation issues, accurately identified 80% of serious LBP events and 93% of LBP disability events.

CONCLUSIONS

In this study cohort, minor trauma does not appear to increase the risk of serious LBP episodes or disability. The vast majority of incident-adverse LBP events may be predicted not by structural findings or minor trauma but by a small set of demographic and behavioral variables.