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18 Articles in Volume 11, Issue #9
Pain and Sleep: A Delicate Balance
Management of Insomnia: Considerations For Patients With Chronic Pain
PPM Editorial Board Outlines Management Strategies for Chronic Pain Patients With Insomnia
Attention Deficit Hyperactivity Disorder And Patients With Pain
Dry Needling Offers Relief From Chronic Low Back Pain
Etiology of Chronic Pain and Mental Illness: How To Assess Both
Temporomandibular Disorder: Examining the Cause And Treatments
Highlights From PAINWeek 2011
Is Your Patient Using Heroin?
Medications For Low Back Pain
Nonpharmacologic Treatments for Patients With Sleep Disorders and Pain
Man With Constant, Daily Headache Pain, Photophobia, Phonophobia, and Nausea
Successful Nonoperative Treatment of Persistently Painful Knees Following Total Knee Arthroplasty—A Case Series
Insomnia in Chronic Pain Patients
What Is Going Wrong With Research? Finding the Right Answer
Testing Positive for Marijuana in Urine
Hydrocodone, Carisoprodol, and Alprazolam—A Most Lethal Combination
Pro-inflammatory Diet

Etiology of Chronic Pain and Mental Illness: How To Assess Both

Part 2 of a three-part series examining the comorbidity of chronic pain and mental health disorders.

Last month in the first part of this three-part series, we explored the biopsychosocial components of chronic pain.1 As psychosocial components have been explored, it has become clear that chronic pain is associated with high rates of mental health disorders. The comorbid relationship between chronic pain and these disorders has been identified in patients with chronic low back pain (LBP), chronic work-related musculoskeletal pain disability, chronic arthritis, headache/migraine, temporomandibular joint disorder (TMD), upper extremity disorders such as carpal tunnel syndrome, fibromyalgia, and a heterogeneous chronic pain group.2-14 Although the prevalence rates differ depending on clinical conditions and clinical contexts, most study patients demonstrated a higher prevalence of depression, anxiety disorders, and substance use disorders compared with those with acute chronic pain or the general population (Table, see page 83).

Among the studies using standard measures for diagnostic assessment (eg, the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders [DSM] [SCID]),15 major depression was commonly present. For example, rates of current major depressive disorder (MDD) ranged from 23% to 78% in chronic pain groups compared with rates of 5% to 17.1% in the general population.16-18 Many patients with chronic pain also appeared to suffer from symptoms of anxiety. Several studies have reported that 10.6% to 62.5% of patients with chronic pain meet current criteria for any anxiety disorder compared with 1% to 25% in the general population.16-18 Current substance use/abuse was frequently found. The percentage of patients with chronic pain meeting current criteria for substance disorders (4.3%-40%) was higher than general population ranges (15%-26.6%).16-18 Although some patient groups reported greater prevalence rates of certain Axis I disorders, the overall prevalence rates in patients with chronic pain were much greater than those in the general population.

In addition, patients with chronic pain were diagnosed with many more Axis II personality disorders than individuals in the general population. Axis II personality disorders have been examined in several studies of DSM diagnoses in individuals with chronic pain, and it has been found that 21% to 70% of patients received some personality disorder diagnosis.3,4,11,14,15 More specifically, personality disorders were very common, with paranoid (9%-33%), borderline (10%-27.5%), and obsessive-compulsive (10%-16.3%) personality disorders, as well as passive-aggressive personality traits (14%-14.9%) being diagnosed in chronic pain patient groups.

Theses prevalence rates suggest a significant association between a chronic pain population and several types of psychopathologic disorders, MDD, anxiety, substance use, and personality disorders. Therefore, it is essential to use a comprehensive assessment battery in order to evaluate the comorbid relationship between chronic pain and psychiatric disorders and then design the most effective treatment plan. This article reviews a number of assessment tests that are commonly available. The third part of the series, which will be published next month, will review treatment of the comorbid patient.

Assessment Tests
Accurately assessing psychopathology in patients with chronic pain is a fundamental component crucial to treatment and the evaluation of outcomes. Unfortunately, there are many barriers present in accurately diagnosing and assessing severity of psychosocial distress. Various methods of assessment used include self-report questionnaires, clinical interviews, and structured interviews. Although no self-report measure can take the place of a trained clinician’s diagnosis, logistical limitations exist, and not every patient can receive a full psychosocial evaluation from a trained clinical psychologist or psychiatrist specializing in chronic pain management. These limitations have been the impetus for the development of a battery of screening instruments that have proven to be quite successful in their ability to diagnose and predict outcomes.19

An increasing number of nonpsychiatric physicians are administering various psychosocial questionnaires during the evaluation process that aid in identifying which patients may need further psychosocial assessment.20 There is even evidence suggesting that the use of psychometric assessment is better than either magnetic resonance imaging (MRI) or diskography in predicting future back pain disability.21,22 The following section lists and briefly explains some of the psychosocial measures and mental health instruments typically used in a full-spectrum assessment of patients with chronic pain.

Million Visual Analog Scale
The Million Visual Analog Scale (MVAS) is a self-report instrument measuring pain perception and subjective disability. It was originally developed by Million and colleagues, with modifications to cutoffs developed by Anagnostis et al.23,24 The MVAS is a 15-question assessment in which each response is rated as a point on a line marked in increments from 0 to 10. The sum of the 15 responses determines the final score on this assessment such that 0 is no disability; 1 to 40 is mild disability; 41 to 70 is moderate disability; 71 to 100 is severe disability; 101 to 130 is very severe disability; and 131 to 150 is extreme disability. The MVAS is particularly useful in instances when patients’ self-report of pain exceeds that which would be projected given physical findings; the psychosocial components are considered in the patients’ disability.25 This measure was originally designed to assess physical functioning and disability related primarily to patients with chronic LBP. The MVAS is effective as a simple disability rating scale and is useful in predicting treatment outcomes for patients with chronic disabling spinal disorders.24

Pain Disability Questionnaire
The Pain Disability Questionnaire (PDQ) is used to measure perceived pain and disability.26 The PDQ is a 15-item questionnaire developed from a collaboration of experienced healthcare professionals and a number of drafts that incorporated various dimensions of other instruments, such as the 36-item Short Form Health Survey [SF-36], MVAS, West Haven–Yale Multidimensional Pain Inventory [MPI], and the Roland-Morris Disability Questionnaire, used in assessing disability status related to pain. Each question presents an analog scale on which patients respond by indicating, on a 10-cm line, their level of pain associated with each domain. The PDQ contains two factors, a functional status component and a psychosocial component. The individual items attributed to each factor are added to generate the score for the two different components, and the total score is composed of all the responses added together. This measure has demonstrated solid psychometric properties, including validity, reliability, and responsiveness to change.26

Oswestry Low Back Pain Disability Questionnaire
The Oswestry Low Back Pain Disability Questionnaire is a 10-item self-rated measure that assesses limitations of various activities of daily living secondary to pain. It was designed specifically for use with an LBP population.27 Each item is scored on a 0- to 5-point scale with a potential range of total scores from 0 to 50, with higher scores indicating increasing levels of disability. When used to assess change in treatment outcomes for patients with chronic pain, this measure is considered a good index of functional limitations within the context of a pain population.28,29

Short-Form Health Evaluation
The SF-36 is a health survey used to assess quality of life related to health status and is reported to have high test–retest reliability coefficients with good internal consistency.30 This measure is widely used for routine monitoring and assessment of healthcare treatment outcomes, assessing both physical and mental components. Although it was not originally developed specifically for a pain population, it has been used as an outcome measure in a number of studies focused on the treatment of pain.31,32 The SF-36 contains eight scales as well as two standardized summary scales that correspond to patients’ overall sense of physical and mental well-being—the Mental Component Scale (MCS) and the Physical Component Scale (PCS). The availability of population-based normative data from various medical populations, such as a spinal population, makes the SF-36 useful for comparative purposes. However, questions remain about its clinical application for assessing outcomes of individual patients. One study’s examination of chronically disabled patients with back pain demonstrated the measure’s good utility when comparing group changes over time but indicated shortcomings when used for individual patient assessments.33 It should be noted that the mental component of this measure incorporates additional information missing in other strictly physical assessment measures. The mental well-being component has been consistently indicated as a factor in the assessment of pain patients.27,34

Beck Depression Inventory-II
The Beck Depression Inventory-II (BDI-II) is a 21-item self-report inventory designed to assess the severity of depressive symptoms.35 Each item is scored from 0 to 3, with a potential range of total scores from 0 to 63. A score ranging from 0 to 13 is considered to be minimal depression; 14 to 19 is mild depression; 20 to 28 is moderate depression; and 29 to 63 indicates severe depression.35 The BDI-II has been demonstrated to be a valid measure of depression symptomatology in patients with chronic pain, and it is a widely used measure for assessing depression levels in a variety of settings. Researchers have discussed the relationship between pain and depression, and the two are thought to be closely related.

The Pain Medication Questionnaire
The Pain Medication Questionnaire (PMQ) is a self-report screening measure containing 26 items based on behavioral correlates and attitudes suggestive of opioid misuse.36 The PMQ is constructed on a 5-point Likert scale ranging from 0 to 4 with various increments that range from disagree to agree, with some items being reverse scored. Greater potential risk for opioid misuse is reflected by an overall higher score.36 The PMQ has been shown to have value in predicting medication misuse.37 The use of this measure has greater implications, as the current focus of many pain management programs addresses the concern of identifying and treating opioid misuse in patients with chronic pain.38

The West Haven–Yale Multidimensional Pain Inventory
The MPI is a 61-item self-report measure that uses a cognitive-behavioral perspective to examine how patients evaluate and manage their pain.39 This assessment evaluates a patient’s perception of pain and results in several coping styles: adaptive, interpersonally distressed, dysfunctional, anomalous, hybrid, or unanalyzable. A normative sample of patients with chronic pain was used in the development of this measure, with good internal consistency and reliability being found.39 This instrument was originally developed and intended to be used for pretreatment evaluation, not as a measure of treatment outcome.40 Concerns have been raised regarding the ability of the MPI to predict outcomes in a chronic pain population. In one study that evaluated the effectiveness of the MPI in predicting response to interdisciplinary treatment in a heterogeneous group of patients with chronic pain, it was found that the MPI subgroup classification did not significantly predict the degree of positive treatment outcomes.40

Minnesota Multiphasic Personality Inventory–Second Edition
The Minnesota Multiphasic Personality Inventory–second edition (MMPI-2) is a self-report questionnaire containing 567 items that provide information on psychiatric symptoms and personality style.41 The questions are partitioned into 10 different scales such that elevation of particular scales or a combination of scales allow for various interpretations. Gatchel and colleagues identified a specific “Disability Profile” for the purpose of identifying patients who may present with distinct complications.42 This profile presents with a minimum of four elevations on the clinical scales. Individuals with such a profile typically lack specific defense mechanisms useful in managing life stressors and thereby experience more severe emotional distress; often, these individuals are resistant to traditional psychiatric treatment approaches.

Clinical Interviews
Clinical interviews require an experienced practitioner to assess each patient individually, addressing issues such as history of mental health disorders and current mental status, allowing for probing of specific areas of concern based on the individual interaction within the context of the interview. The previously discussed self-report measures can be an important initial aspect of this clinical interview, as they often give the clinician insight into which topics might need further exploration. Clinical interviews are an excellent method for identifying specific needs and establishing a therapeutic rapport useful in treatment. However, clinical research efforts find this approach too vague and call for a more quantifiable, standardized approach to assessment. The structured clinical interview addresses this concern.

Structured Clinical Interviews
Assessing psychopathology in clinical research often involves the use of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II).43,44 The SCID-I is a structured interview that yields Axis I diagnoses that correspond with DSM-IV criteria. The diagnoses most commonly studied in the context of a chronic pain population include MDD, generalized anxiety disorder, and substance use disorders. The SCID-II is also a structured interview that identifies Axis II personality disorders defined with DSM-IV criteria. The diagnoses provided by the SCID-II allow for individual personality disorders to be categorized into three clusters: cluster A (odd, eccentric, and suspicious individuals); cluster B (dramatic, emotional, and erratic individuals); and cluster C (anxious and fearful individuals).45 The SCID allows for the determination of current and lifetime diagnoses of psychopathology that are useful in determining whether the current pain episode preceded the occurrence of psychopathology or vice versa.10 Through the use of the SCID, the symptoms associated with the onset of pain can be distinguished from true psychopathology, which is necessary for accurate treatment planning with patients with chronic pain.

Proper assessment is vital to individually tailoring the appropriate treatment for this critically vulnerable population. Identifying specific comorbid conditions is helpful in the establishment of a tailored treatment plan for the individual’s physical, emotional, social, and vocational needs. Providing a successful treatment modality often depends on certain factors that these assessments help clarify.

The comprehensive biopsychosocial approach is ideally suited to address this comorbidity issue because it views physical disorders, such as pain, as a result of complex and dynamic interactions among physiologic, psychological, and social factors that perpetuate and may even worsen the clinical presentation. As we have detailed, careful patient assessment is essential before any attempt is made to develop a comprehensive pain management intervention strategy. Such an initial assessment should proceed from a global biopsychosocial diagnosis of pain to a more detailed evaluation of the most important interactive factors of this diagnosis. Once the comprehensive assessment is completed, it can be used to develop a treatment program individually tailored for each patient.

The final installment of this series will discuss the treatment of comorbid pain and mental health disorders.

Last updated on: May 12, 2015
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