Pain
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Randomized Controlled Trial
Categories of placebo response in the absence of site-specific expectation of analgesia.
Experimental placebo analgesia is induced by building an expectation of reduced pain in a specific body part, usually using an inert cream in the guise of a local anaesthetic in conjunction with conditioning. We investigated non-site-specific placebo analgesia by conditioning subjects to expect the anaesthetic cream on one arm, without specifying if they will definitely receive the cream, or to which arm it might be applied. Painful heat pulses (150 ms) from a CO2 laser were delivered randomly to both arms. ⋯ In the treatment group, we observed a range of placebo responses: unilateral responders (33.3%), subjects with a placebo response in the conditioned arm only; bilateral responders (33.3%), subjects reporting reduction in the intensity ratings in both arms, and non-responders, whose intensity ratings were not influenced by conditioning. We discuss these responses in terms of different levels of expected analgesia, facilitated by the absence of a site-specific focus for the treatment. We suggest this allowed the individuals suggestibility to influence their assessment of the pain experience by combining different levels of expectation with the information from the actual pain stimulus.
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Functional magnetic resonance imaging (fMRI) of blood oxygen level dependent (BOLD) haemodynamic responses was used to study the effects of the noxious substance capsaicin on whole brain activation in isofluorane anaesthetised rats. Rats (n=8) received intradermal injection of capsaicin (30 microg/5 microl), or topical cream (0.1%) capsaicin and BOLD responses were acquired for up to 120 min. Effects of capsaicin versus placebo cream treatment on the BOLD response to a 15 g mechanical stimulus applied adjacent to the site of cream application were also studied. ⋯ Capsaicin also produced increases in BOLD signal intensity in other regions that contribute to pain processing, such as the parabrachial nucleus and superior colliculus. Mechanical stimulation in capsaicin-treated rats, but not placebo-treated rats, induced a significant decrease in BOLD signal intensity in the PAG (p<0.001). These data demonstrate that the noxious substance capsaicin produces brain activation in the midbrain regions and reveals the importance of the PAG in central sensitization.
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Chronic pain has adverse effects on individuals with chronic pain (ICPs) as well as their family members. Borrowing from an empathy model described by Goubert et al. (2005), we examined top-down and bottom-up factors that may be related to psychological well-being in the spouses of ICPs. A diverse community sample of 113 middle-aged spouses of individuals with chronic pain (ICPs) completed measures on pain severity and spouse pain catastrophizing (PCS-S; Cano et al., 2005). ⋯ However, when both partners reported chronic pain, there was no significant difference in psychological distress between partners. Hierarchical regression analyses showed that spouse magnification catastrophizing was associated with depressive and anxiety symptoms, and that helplessness catastrophizing was associated with depressive symptoms for spouses of ICPs who also reported chronic pain but not for spouses of ICPs without chronic pain. The results are discussed in light of interpersonal processes that may affect spouses' distress.
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Randomized Controlled Trial
Adjunctive self-hypnotic relaxation for outpatient medical procedures: a prospective randomized trial with women undergoing large core breast biopsy.
Medical procedures in outpatient settings have limited options of managing pain and anxiety pharmacologically. We therefore assessed whether this can be achieved by adjunct self-hypnotic relaxation in a common and particularly anxiety provoking procedure. Two hundred and thirty-six women referred for large core needle breast biopsy to an urban tertiary university-affiliated medical center were prospectively randomized to receive standard care (n=76), structured empathic attention (n=82), or self-hypnotic relaxation (n=78) during their procedures. ⋯ Pain increased significantly in all three groups (logit slopes: standard care=0.53, empathy=0.37, hypnosis=0.34; all p<0.001) though less steeply with hypnosis and empathy than standard care (p=0.024 and p=0.018, respectively). Room time and cost were not significantly different in an univariate ANOVA despite hypnosis and empathy requiring an additional professional: 46 min/161 dollars for standard care, 43 min/163 dollars for empathy, and 39 min/152 dollars for hypnosis. We conclude that, while both structured empathy and hypnosis decrease procedural pain and anxiety, hypnosis provides more powerful anxiety relief without undue cost and thus appears attractive for outpatient pain management.
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Living with chronic pain is associated with many deleterious outcomes, including a substantially increased risk of suicide. While many general risk factors for suicidal ideation and behavior have been identified, few studies have examined pain-related factors that confer increased or decreased risk for suicidality. The present study assessed individual differences in the use of pain-related coping strategies and pain-related catastrophizing as correlates of suicidal ideation in patients with chronic pain. ⋯ Demographic and other pain-related variables such as pain severity and duration were not generally robust predictors of suicidal ideation in this sample of patients with chronic pain. These are the first findings to suggest a unique (e.g., independent of pain severity or depressive symptomatology) association between pain-coping strategies and suicide-related cognitions in the context of chronic pain. Further research in this area, including the addition of suicide prevention materials to pain-coping skills training programs, may benefit large numbers of individuals who are at elevated suicide risk as a consequence of chronic pain.