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 Of these 57 completed the trial; of the 21 who did not complete, four were withdrawn because of adverse effects.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.

Patients with chronic pain frequently report that changes in the weather influence their pain. This study investigated differences in the perceived influence of weather on pain among 558 chronic pain patients living in 4 cities (San Diego, California; Nashville, Tennessee; Worcester, Massachusetts; and Boston, Massachusetts) in the United States. Local climatologic data for each city were obtained from the National Climatic Data Center. All patients completed a weather questionnaire, and the information they provided was compared with demographic and weather variables. The majority of all patients believed that changes in the weather affected their pain. Pain patients who were younger and who had arthritis reported the most sensitivity to changes in weather. Weather sensitivity was unrelated to all other demographic variables and to geographic region. Cold and damp conditions were considered to influence pain the most. However, the perceived effect of weather on pain was not found to be related to regional climate. Thus, the belief that pain is worsened by living in a colder climate was not supported. An equilibrium theory of weather changes and pain is discussed. Further investigations are needed to identify the mechanisms involved in the effects of weather changes on pain.

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.

To understand the relative efficacy of noradrenergic and serotonergic antidepressants as analgesics in chronic back pain without depression, we conducted a randomized, double-blind, placebo-control head-to-head comparison of maprotiline (a norepinephrine reuptake blocker) and paroxetine (a serotonin reuptake blocker) in 103 patients with chronic low back pain. Of these 74 completed the trial; of the 29 who did not complete, 19 were withdrawn because of adverse effects. The intervention consisted of an 8-week course of maprotiline (up to 150 mg daily) or paroxetine (up to 30 mg daily) or an active placebo, diphenhydramine hydrochloride (up to 37.5 mg daily). Patients were excluded for current major depression. Reduction in pain intensity (Descriptor Differential Scale scores) was significantly greater for study completers randomized to maprotiline compared to placebo (P=0.023), and to paroxetine (P=0.013), with a reduction of pain by 45% compared to 27% on placebo and 26% on paroxetine. These results suggest that at standard dosages noradrenergic agents may provide more effective analgesia in back pain than do selective serotonergic reuptake inhibitors.

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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.

Gabapentin is prescribed for analgesia in chronic low back pain, yet there are no controlled trials supporting this practice. This randomized, two-arm, 12-week, parallel group study compared gabapentin (forced titration up to 3600 mg daily) to inert placebo. The primary efficacy measure was change in pain intensity from baseline to the last week on treatment measured by the Descriptor Differential Scale; the secondary outcome was disability (Oswestry Disability Index). The intention-to-treat analysis comprised 108 randomized chronic back pain patients (daily pain for ≥ 6 months) whose pain did (43%) or did not radiate into the lower extremity. Random effects regression models which did not impute missing scores were used to analyze outcome data. Pain intensity decreased significantly over time (p < .0001) with subjects on gabapentin or placebo reporting reductions of about 30% from baseline, but did not differ significantly between groups (p = .423). The same results pertained for disability scores. In responder analyses of those who completed 12 weeks (N=72), the proportion reporting at least 30% or 50% reduction in pain intensity, or at least “Minimal Improvement” on the Physician Clinical Global Impression of Change did not differ significantly between groups. There were no significant differences in analgesia between participants with radiating (n = 46) and non-radiating (n = 62) pain either within or between treatment arms. There was no significant correlation between gabapentin plasma concentration and pain intensity. Gabapentin appears to be ineffective for analgesia in chronic low back pain with or without a radiating component.

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.