The journal of pain : official journal of the American Pain Society
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A cross-sectional, Internet-based survey was conducted in a nationally representative sample of United States (US) adults to estimate the point prevalence of chronic pain and to describe sociodemographic correlates and characteristics of chronic pain. The survey was distributed to 35,718 members (aged 18 years and older) of a Web-enabled panel that is representative of the US population, and 27,035 individuals responded. Crude and weighted prevalence estimates were calculated and stratified by age, sex, and type of chronic pain. The weighted point-prevalence of chronic pain (defined as chronic, recurrent, or long-lasting pain lasting for at least 6 months) was 30.7% (95% CI, 29.8-31.7). Prevalence was higher for females (34.3%) than males (26.7%) and increased with age. The weighted prevalence of primary chronic lower back pain was 8.1% and primary osteoarthritis pain was 3.9%. Half of respondents with chronic pain experienced daily pain, and average (past 3 months) pain intensity was severe (≥ 7 on a scale ranging from 0 to 10) for 32%. Multiple logistic regression analysis identified low household income and unemployment as significant socioeconomic correlates of chronic pain. Chronic pain is prevalent among US adults and is related to indicators of poorer socioeconomic status. ⋯ The results of this cross-sectional Internet-based survey suggest a considerable burden of chronic pain in US adults. Chronic pain, experienced by about a third of the population, was correlated with indicators of poorer socioeconomic status. Primary chronic pain was most commonly attributed to lower back pain, followed by osteoarthritis pain.
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Based on prior research identifying dispositional optimism as a predictor of placebo responding, the present study tested the hypothesis that individuals high in optimism would be more likely to respond to a placebo analgesic. Optimists and pessimists were randomly assigned to a placebo expectation condition or a no expectation condition before a cold pressor task. Blood pressure and heart rate were recorded before and during the cold pressor task, and participant ratings of pain and expectations were obtained immediately after the task. Analysis of the expectation manipulation revealed that the placebo instruction was successful in altering participant expectancy during the cold pressor. Supporting the main hypothesis, dispositional optimism was associated with lower pain ratings in the placebo condition but not in the control condition. Because dispositional optimism can alter placebo responding to laboratory pain, future studies should examine the potential role that this individual difference factor may play in patient responsivity to pharmacological and nonpharmacological treatments for clinical pain. ⋯ This study examined the possibility that individual differences can predict placebo analgesia. Participants were randomly assigned to receive either a placebo expectation or no expectation before a cold pressor task. Dispositional optimism was related to less cold pressor pain in the placebo condition as compared with the control condition.
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Although most cases of temporomandibular muscle and joint disorders (TMJD) are mild and self-limiting, about 10% of TMJD patients develop severe disorders associated with chronic pain and disability. It has been suggested that fibromyalgia and widespread pain play a significant role in TMJD chronicity. This paper assessed the effects of fibromyalgia and widespread pain on clinically significant TMJD pain (GCPS II-IV). Four hundred eighty-five participants recruited from the Minneapolis/St. Paul area through media advertisements and local dentists received examinations and completed the Graded Chronic Pain Scale (GCPS) at baseline and at 18 months. Baseline widespread pain (OR: 2.53, P = .04) and depression (OR: 5.30, P = .005) were associated with onset of clinically significant pain (GCPS II-IV) within 18 months after baseline. The risk associated with baseline fibromyalgia was moderate, but not significant (OR: 2.74, P = .09). Persistence of clinically significant pain was related to fibromyalgia (OR: 2.48, P = .02) and depression (OR: 2.48, P = .02). These results indicate that these centrally generated pain conditions play a role in the onset and persistence of clinically significant TMJD. ⋯ Fibromyalgia and widespread pain should receive important consideration when evaluating and developing a treatment plan for patients with TMJD.
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Comparative Study
A comparison of the DN4 and LANSS questionnaires in the assessment of neuropathic pain: validity and reliability of the Turkish version of DN4.
A screening tool that quickly and correctly differentiates neuropathic pain from non-neuropathic pain is essential. Although there are many screening tools in the assessment of neuropathic pain, many physicians still have the problem of not being able to identify their neuropathic pain patients easily. In this study, we assessed the test-retest reliability, internal consistency, and validity of the Turkish version of DN4 questionnaire. Within the same group of patients, we also compared the DN4 with the LANSS questionnaire. A total of 180 patients (n = 121 with neuropathic pain and n = 59 with non-neuropathic pain characteristics) were enrolled. In our study population, peripheral origin of neuropathic pain, mainly radiculopathies and polyneuropathies, dominated. The reliability and validity of Turkish version of DN4 were found to be high. The sensitivities of the DN4 and the LANSS were 95% and 70.2%, respectively. The specificity of both tests was 96.6%. The strengths and weaknesses of these questionnaires are discussed. ⋯ The Turkish version of DN4 questionnaire is reliable and valid. It is also an easier, quicker, and more sensitive screening tool (1-minute test) compared with the Turkish version of LANSS questionnaire. These features of the DN4 may help clinicians to identify their neuropathic pain patients accurately in daily clinical practice and research studies.
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Comparative Study
Salivary cortisol release and hypothalamic pituitary adrenal axis feedback sensitivity in fibromyalgia is associated with depression but not with pain.
Results on hypothalamicpituitary-adrenal (HPA) axis function in fibromyalgia are heterogeneous and studies that integrate psychological and biological mechanisms in the search for pathways to fibromyalgia are rare. The goal of the study was to evaluate cortisol release and HPA axis feedback regulation in fibromyalgia and its association with psychopathology and pain. Beneath assessment of pain thresholds and self-report of pain, salivary free cortisol release over the day before and after intake of 0.5 mg of dexamethasone was measured in 21 female patients with fibromyalgia and 26 control women. Depression was assessed by questionnaires and clinical interview. We found reduced feedback sensitivity and slightly enhanced cortisol release in patients with fibromyalgia compared with healthy control subjects. Post hoc analyses showed that these effects are exclusively found in those patients, who also had major depressive disorder. Patients with fibromyalgia had lower pain pressure threshold, whereas heat pain thresholds were comparable with control subjects. Pain pressure and heat pain thresholds were not associated with cortisol release. On the other hand measurements of affective pain experience and depression were positively correlated with salivary cortisol over the day. Our results support the hypotheses that HPA axis related alterations are associated with affective disturbances, for example, depression, in patients with fibromyalgia. ⋯ The presented data suggest depression to be an important factor in HPA axis-related dysfunction in fibromyalgia. This might be one explanation for equivocal findings in the literature.