Pain
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Randomized Controlled Trial
Treating pain with pain: supraspinal mechanisms of endogenous analgesia elicited by heterotopic noxious conditioning stimulation.
While being exposed to an intensive tonic pain stimulus at one area of the body, another phasic pain stimulus applied to a remote site is perceived as less painful. The neurophysiological basis for this "pain inhibits pain" phenomenon has been presumed to be an activation of the spino-bulbo-spinal mechanism termed "diffuse noxious inhibitory controls." However, several additional mechanisms such as an activation of the descending pain control system may contribute to this observation. Here we investigated the underlying supraspinal mechanisms of "heterotopic noxious conditioning stimulations" (HNCS), representing this specific experimental constellation. ⋯ These effects were in part reversed by naloxone, speaking for the contribution of endogenous opioid neurotransmission to this mechanism. Taken together, these results demonstrate a substantial contribution of higher-order brain regions to the phenomenon of hypoalgesia during HNCS. Functional magnetic resonance imaging shows how the human brain is involved in heterotopic noxious conditioning and reveals active supraspinal pain modulatory mechanisms during dual pain stimulation.
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The fear avoidance model of pain (FAM) conceptualizes pain catastrophizing as the cognitive antecedent of pain-related fear, and pain-related fear as the emotional antecedent of depression and disability. The FAM is essentially one of mediation whereby pain-related fear becomes the process by which depression or disability ensue. However, emerging literature suggests that pain catastrophizing, pain-related fear, and depression might be at least partially distinct in their prediction of different pain-related outcomes. ⋯ After controlling for pain intensity and FAM variables, pain self-efficacy was shown to be a unique predictor of medication use. Implications for the FAM and the clinical management of musculoskeletal pain conditions are discussed. Unique relationships were found between pain catastrophizing and long-term pain intensity, between fear of movement and long-term work disability, and between pain self-efficacy and medication use at one-year follow-up.
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Chronic pain not only interferes with daily activities, it may also have a negative impact on the perceived integrity of one's self through self-discrepancies. Self-discrepancies are experienced distances between the actual self and self-guides that can exist from 2 perspectives (ie, own and other). Self-discrepancies are associated with negative mood states and incite self-regulatory behavior in order to reduce these discrepancies. ⋯ In contrast to expectations, none of the other self-discrepancies was related to activity patterns. Of interest was that avoidance, but not persistence behavior, was predictive of higher levels of disability and lower levels of quality of life. Support is provided for the role of self-discrepancies in the emotional well-being and behavioural patterns of patients with chronic low back pain.
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Forty-five women with fibromyalgia (FM) engaged in a 30-day electronic diary assessment, recording daily ratings of pain and 2 forms of maladaptive coping: pain catastrophizing and pain attention. Participants were genotyped for the val(158)met single nucleotide polymorphism (rs4680) in the catechol-O-methyltransferase (COMT) gene. COMT genotype moderated the daily relations of both maladaptive coping processes and pain. ⋯ Further, the findings advance our understanding of the role of COMT in FM, suggesting that genetic variation in the val(158)met polymorphism may affect FM pain through pathways of pain-related cognition. This study examined 2 forms of maladaptive coping: pain catastrophizing and pain attention. The findings provide multimeasure and multimethod support for genetic moderation of a maladaptive coping and pain process and suggest that genetic variation in the val(158)met polymorphism may affect fibromyalgia pain through pathways of pain-related cognition.
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The role of anxiety in pain is less well understood than the role of depression. Based on recent conceptual thinking about worry and pain, we explored the relationship between pain status and worry about health and anxiety in 1217 community-dwelling men aged 70 years or older who participated in the baseline phase of the Concord Health and Ageing in Men Project study, a large population-based epidemiological study of healthy ageing based in Sydney, Australia. We hypothesised that worry about health would be associated with having persistent pain, and that the association would be stronger in the presence of co-existing pain-related interference with activities (intrusive pain). ⋯ These findings suggest that at a population level, subthreshold anxiety and pain are strongly related, and worry about health occurs much more commonly than anxiety itself. To our knowledge, this is the first study to explore, specifically, the relationship between pain status and worry about health in older men. In older community-dwelling men, pain was robustly associated with worry about health, highlighting the potential importance of subthreshold anxiety-related psychological factors.