A randomized, controlled trial of acceptance and commitment therapy and cognitive-behavioral therapy for chronic pain.

Individuals reporting chronic, nonmalignant pain for at least 6 months (N=114) were randomly assigned to 8 weekly group sessions of acceptance and commitment therapy (ACT) or cognitive-behavioral therapy (CBT) after a 4-6 week pretreatment period and were assessed after treatment and at 6-month follow-up. The protocols were designed for use in a primary care rather than specialty pain clinic setting. All participants remained stable on other pain and mood treatments over the course of the intervention. ACT participants improved on pain interference, depression, and pain-related anxiety; there were no significant differences in improvement between the treatment conditions on any outcome variables. Although there were no differences in attrition between the groups, ACT participants who completed treatment reported significantly higher levels of satisfaction than did CBT participants. These findings suggest that ACT is an effective and acceptable adjunct intervention for patients with chronic pain.

A placebo-controlled randomized clinical trial of nortriptyline for chronic low back pain.

To assess the efficacy of nortriptyline, a tricyclic antidepressant, as an analgesic in chronic back pain without depression, we conducted a randomized, double-blind, placebo-controlled, 8-week trial in 78 men recruited from primary care and general orthopedic settings, who had chronic low back pain (pain at T-6 or below on a daily basis for 6 months or longer). Of these 57 completed the trial; of the 21 who did not complete, four were withdrawn because of adverse effects. The intervention consisted of inert placebo or nortriptyline titrated to within the therapeutic range for treating major depression (50-150 ng/ml). The main outcome endpoints were pain (Descriptor Differential Scale), disability (Sickness Impact Profile), health-related quality of life (Quality of Well-Being Scale), mood (Beck Depression Inventory, Spielberger State Anxiety Inventory, Hamilton Anxiety/Depression Rating Scales), and physician rated outcome (Clinical Global Impression). Reduction in pain intensity scores was significantly greater for participants randomized to nortriptyline (difference in mean change 1.68, 95%-0.001, CI -3.36, P = 0.050), with a reduction of pain by 22% compared to 9% on placebo. Reduction in disability marginally favored nortriptyline (P = 0.055), but health-related quality of life, mood, and physician ratings of overall outcome did not differ significantly between treatments. Subgroup analyses of study completers supported the intent-to-treat analysis. Also, completers with radicular pain on nortriptyline (n = 5) had significantly (P < 0.05) better analgesia and overall outcome than did those on placebo (n = 6). The results suggest noradrenergic mechanisms are relevant to analgesia in back pain. This modest reduction in pain intensity suggests that physicians should carefully weigh the risks and benefits of nortriptyline in chronic back pain without depression.

One-year follow-up of first onset low back pain.

Efforts to examine the process and risk of developing chronic back pain have relied generally upon retrospective study of individuals with already established pain. In an alternative approach to understanding the clinical course and evolution of low back disorders, a cohort of 76 men experiencing their first episode of back pain was assessed prospectively at 2, 6 and 12 months following pain onset. Standard measures of pain (Descriptor Differential Scale: DDS), disability (Sickness Impact Profile: SIP), and distress (Beck Depression Inventory: BDI) were employed to classify the sample into five groups: Resolved, Pain Only, Disability/Distress Only, Pain and Mild Disability/Distress, and Clinical Range. At both 6 and 12 months post pain onset, most (78%, 72% respectively) of the sample continued to experience pain. Many also experienced marked disability at 6 months (26%) and 12 months (14%). At 12 months, no participants had worsened relative to the 2-month baseline. Doubly multivariate analyses of variance (MANOVAs) were employed to compare baseline groups (Pain Only, Pain and Mild Disability/Distress, Clinical Range) on the DDS, SIP, and BDI across time. The group by time interaction from 2 through 12 months was reliable, with greatest change occurring in the Clinical Range group in disability and distress; interestingly, the decrease in pain was comparable among all groups. Follow-up tests across measures demonstrated greater change in the early (2-6-month) interval and relative stability in the later (6-12-month) interval. Comparison of those classified as 'improvers' with those who did not improve from 2 to 12 months showed similar findings. The clinical course of first onset back pain may be prolonged for many patients, and involves a continuum of related disability and distress. Individuals at risk for marked symptoms 1 year after an initial episode of back pain can be identified early, and prompt treatment might reduce the risk of pain chronicity.

Psychosocial factors discriminate multidimensional clinical groups of chronic low back pain patients.

Previous studies have empirically defined clinical subgroups of chronic low back pain (CLBP) patients, based on differing patterns of pain, disability and emotional distress. Because these identified groups generally are comparable in terms of physical and demographic variables, variation in functional status cannot be adequately explained by medical or social factors. In the present study we evaluated whether other psychosocial factors (stress, coping attempts, and satisfaction with social supports) might differentiate the observed groups. A discriminate function analysis indicated that ratings of life adversity, coping, and social support statistically differentiate clinical groups of CLBP patients. Patients categorized as chronic pain syndrome (i.e., high levels of pain, disability and depression) reported greater life adversity, more reliance on passive/avoidant coping strategies, and less satisfaction with social support networks. Patients categorized as having good pain control (i.e., low levels of pain, disability and depression) reported less life adversity, less reliance on passive/avoidant coping strategies, and more satisfaction with social support networks. Finally, a mixed picture of less life adversity, but more reliance on passive/avoidant coping strategies and more satisfactory social support networks was reported by patients categorized in the positive adaptation to pain group (i.e., high levels of pain, but relatively low levels of disability and depression). These findings suggest that psychosocial factors may be important and complex correlates of multidimensional clinical presentations of CLBP. Psychosocial factors may also offer an avenue for intervention across 3 key dimensions of CLBP.

The Descriptor Differential Scale of Pain Intensity: an evaluation of item and scale properties.

Improved methods for pain measurement have both theoretical and clinical importance. This study evaluated the Descriptor Differential Scale (DDS) of Pain Intensity, a recent methodology designed for assessing pain reports in clinical samples. Experiment 1 evaluated the sensitivity of the measure to small changes in electrocutaneous stimulation relative to a traditional visual analogue scale (VAS) of pain intensity. Additionally, direct psychophysical scaling methods were employed to determine ratio-scale values for the DDS sensory items in relation to the electrocutaneous stimuli. This ratio scale was cross-validated by comparison with previously published ratio-scaled data from cross-modality matching pain intensity judgement studies. Experiment 2 evaluated the performance of the measure in both experimental and clinical pain samples, as well as the similarity of item-response patterns in each of these samples. Results indicate that the DDS of Pain Intensity is sensitive to small changes in electrocutaneous stimulation, has consistent ratio-scale properties across two different psychophysical methods, and demonstrates similar item-response patterns across divergent experimental and clinical samples. The results support the validity of the sensory DDS as a measure of pain intensity.

An empirical evaluation of multidimensional clinical outcome in chronic low back pain patients.

Individuals with persisting pain often present a constellation of symptoms that includes pain, health-related impairment and dysphoric mood. It is now widely accepted that comprehensive assessment must address each of these dimensions. Despite recognition of the value of multidimensional assessment, no empirical efforts have validated the construct of a multidimensional clinical outcome presentation based on the dimensions of pain, impairment and dysphoric mood. We employed cluster analytic procedures on standard measures of pain, impairment and depression in chronic low back pain (CLBP) patients (n = 96) attending a general orthopedic clinic in order to empirically characterize multidimensional clinical outcomes. Results indicated that 3 groups could be identified reliably: (1) 'Chronic Pain Syndrome' (n = 25; high levels of pain, impairment and depression), (2) 'Positive Adaptation to Pain' (n = 24; high levels of pain with low levels of impairment and depression) and (3) 'Good Pain Control' (n = 47; low levels of pain, impairment and depression). The reliability of this cluster solution was supported by several tests of internal consistency. Discriminability of the clusters was examined across both the outcome measures themselves and several additional independent variables. The cluster solution was then cross-validated in an independent sample of pain clinic CLBP patients (n = 180) to test its generalizability. Finally the stability of the cluster dimensions over time was tested by re-assessing 36 CLBP patients 6 months after they initially were characterized into 1 of the 3 outcome groups on the same measures. MANOVA results indicated that the outcome groups were differentiated statistically across assessments. The multiple outcome measures did not change significantly across time, nor did the outcome groups change differentially across time on these measures. We conclude that the outcome dimensions of pain, impairment and depression are relatively stable phenomena that differentially describe CLBP patients.

Coping activities in chronic low back pain: relationship with depression.

To help clarify the nature of coping activities in chronic pain, this study compared how depressed (n = 37) and non-depressed (n = 40) chronic low back pain (CLBP) patients attempted to cope with pain-specific and general non-pain life stressors, relative to matched healthy control subjects (n = 40). We hypothesized that depressed mood, rather than pain alone, would account for differences in coping activities between groups. Specifically, we expected that depressed CLBP patients would report a greater proportion of passive and avoidant coping responses and less active problem solving coping attempts than non-depressed patients and controls. Results indicated that depressed CLBP patients reported more passive-avoidant coping activities than did non-depressed CLBP patients and controls, whereas coping responses were similar for non-depressed CLBP patients and controls. Additionally, subjects across groups tended to report more passive-avoidant coping in response to the specific back pain stressor (i.e., exacerbation of back pain during activity) than to other life stressors. Finally, the magnitude of reported differences in coping attempts across groups varied as a function of the type of stressor (i.e., specific back pain stressor vs. general stressful life events), particularly with regard to a disinclination to seek social support in response to the back pain exacerbation. We conclude that: (1) chronic back pain patients may employ different coping activities when attempting to manage pain exacerbations than when confronting more general life stressors, and (2) an increased rate of passive-avoidant coping responses (relative to matched health controls) is associated with the combination of CLBP and concurrent depressed mood, rather than with CLBP alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence, onset, and risk of psychiatric disorders in men with chronic low back pain: a controlled study.

This study used structured diagnostic interviews and DSM-III criteria to assess lifetime prevalence and pre-morbid risk of psychiatric disorder in a sample of men with long-standing chronic back pain (CLPB) attending a primary care clinic. A control group of age and demographically matched men without history of back pain was also studied. Compared to controls, men with CLBP had significantly higher lifetime rates of major depression (32% vs. 16%), alcohol use disorder (64.9% vs. 38.8%), and a major anxiety disorder (30.9% vs. 14.3%). Almost all CLBP men ever experiencing a mood disorder reported recurrent, not single, episodes. The 6 month point prevalence of major depression, but not other disorders, was also significantly elevated for men with CLBP. In CLBP, the first episode of major depression generally (58.1%) followed pain onset. While the initial major depressive episode usually commenced within the first 2 years of established pain, late onset mood disorder was also common. By comparison in most cases (81%) onset of alcohol use disorders considerably preceded pain. When an age-matching procedure was used to gauge relative vulnerability to psychiatric illness in patients and controls, CLBP patients had significantly higher pre-pain rates of alcohol use disorder but not depression. After age of pain onset, CLBP subjects had over 9 times the risk of developing major depression, but had similar rates of developing alcoholism. We conclude that (1) alcohol use disorders rather than depression may increase risk of developing CLBP, and (2) risk of new onset and recurrent major depression remains high for men throughout their pain career. This suggests that psychological adaptation to long-standing pain may be less successful than previously thought, especially with regard to recurrent mood disorder.

Pain and impairment beliefs in chronic low back pain: validation of the Pain and Impairment Relationship Scale (PAIRS).

Few validated instruments are available to assess beliefs and attitudes that patients have regarding pain, or ability to function despite discomfort. The Pain and Impairment Relationship Scale (PAIRS) was developed to tap these important beliefs and attitudes in chronic pain patients. Preliminary data indicate that the PAIRS is internally consistent and significantly related to impairment in a highly selected pain clinic sample of patients, including some chronic low back pain patients. The present study was designed to extend the validation of the PAIRS to a more general sample of chronic benign low back pain patients. Furthermore, additional tests supported the discriminant, convergent and divergent validity, as well as the reliability and relative independence from favorable self-report response bias of the PAIRS, by respectively demonstrating that: (1) the impairment beliefs assessed with the PAIRS were more prominent in chronic low back pain (CLBP) patients than in matched non-pain, healthy controls; (2) scores on the PAIRS were significantly related to measures of physical impairment, but not to physicians ratings of disease severity; (3) the impairment beliefs assessed with the PAIRS are readily distinguishable from cognitive distortions and emotional distress; (4) PAIRS scores for chronic low back pain patients are relatively consistent over time; and (5) PAIRS scores are not significantly associated with measures of favorable self-report response bias. We conclude that the PAIRS has demonstrated at least preliminary utility for applications by researchers and clinicians interested in chronic pain.

Depression in spouses of chronic pain patients: the role of patient pain and anger, and marital satisfaction.

Although several studies have shown that spouses of chronic pain patients may experience clinically significant depressive symptoms few studies have comprehensively examined the role of both patient and spouse-related factors in the development and maintenance of this emotional distress. Twenty-nine married male chronic benign low back pain patients and their spouses were recruited in order to examine the role of patient, spouse, and marital factors in spouse depressive symptomatology. The results indicated that 28% percent of the spouses in the sample reported significantly depressed mood. A 2-stage regression analysis was employed that revealed 3 significant predictors of spouse's depressed mood, namely patient's average pain; patient's reported levels of anger and hostility, and the spouse's level of marital satisfaction. These findings are discussed in terms of their implications for clinical interventions for pain patients and their families.

The language of pain: affective descriptors of pain are a better predictor of psychological disturbance than pattern of sensory and affective descriptors.

The language used by chronic benign pain patients to characterize their pain complaint was analyzed to determine the best predictor of psychiatric disturbance. Using the 78 adjectives provided by the McGill Pain Questionnaire, the number of affective descriptors used was the best predictor of psychiatric disturbance. Addition of sensory descriptors either to augment the total number of descriptors used (magnitude) or as a pattern of sensory greater than affective or sensory less than affective failed to increase predictive strength.

Pain measurement: the affective dimensional measure of the McGill pain questionnaire with a cancer pain population.

Two experiments used the McGill Pain Questionnaire (MPQ) to examine the affective dimension of pain in patients whose pain was secondary to malignancy. In experiment I, segregating groups of cancer patients on the basis of extreme scores (high versus low) on the MPQ failed to produce segregation on independent measures of affect and infirmity. This outcome contrasts with earlier work with chronic benign pain patients. Experiment II compared cancer pain patients matched with benign pain patients on intensity of pain report on the affective dimension of the MPQ. Cancer pain patients reported a reliably higher affective loading to their pain. These data suggest that cancer pain patients employ different criteria than benign pain patients in selecting affective pain descriptors. Possible explanations for this difference are discussed.

Pain measurement: construct validity of the affective dimension of the McGill Pain Questionnaire with chronic benign pain patients.

The research reported here used a population of chronic benign pain patients and examined the relationship between scores in the affective dimension of the McGill Pain Questionnaire and independent measures of affect and infirmity The data indicated that patients who reported high affective dimensional scores were significantly more depressed and anxious and somatized more than patients who reported low effective scores. Similarly, these high affective patients reported significantly greater perceived infirmity secondary to their pain. These results suggest that the affective dimension score of the McGill Pain Questionnaire can serve as a useful index of the overall affective status of pain patients and given this interpretation the dimension has good construct validity.

Measurement of pain: patient preference does not confound pain measurement.

Chronic pain patients reported pain intensity on each of 3 pain intensity scales, the visual analog, numerical and adjectival scales, and then ranked the scales in order of perceived best communication of pain intensity. All patients were able to complete an adjectival scale but 11% were unable to complete a visual analog scale and 2% failed at a numeric scale. The intensity of the pain ratings on the 3 scales were significantly correlated and there were no reliable differences in reported intensity as a function of preference. Pain intensity was reliably higher on each scale for depressed-anxious patients as compared to non-depressed/non-anxious patients. Patients completing all 3 scales indicated a significant preference for the adjectival scale but the basis for this preference did not appear related to sex, etiology of pain, affective variables nor selected psychological variables. These data indicate that pain scale preference does not influence pain intensity report. Nevertheless, there are some clinical situations in which a numeric scale is likely to yield a better measure of pain intensity.