Pain
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Little is known about patients prescribed high doses of opioids to treat chronic non-cancer pain, though these patients may be at higher risk for medication-related complications. We describe the prevalence of high-dose opioid use and associated demographic and clinical characteristics among veterans treated in a VA regional healthcare network. Veterans with chronic non-cancer pain prescribed high doses of opioids (≥ 180 mg/day morphine equivalent; n=478) for 90+ consecutive days were compared to two groups with chronic pain: Traditional-dose (5-179 mg/day; n=500) or no opioid (n=500). ⋯ After controlling for demographic factors and VA facility, neuropathy, low back pain, and nicotine dependence diagnoses were associated with increased likelihood of high-dose prescriptions. High-dose patients frequently did not receive care consistent with treatment guidelines: there was frequent use of short-acting opioids, urine drug screens were administered to only 25.7% of patients in the prior year, and 32.0% received concurrent benzodiazepine prescriptions, which may increase risk for overdose and death. Further study is needed to identify better predictors of high-dose usage, as well as the efficacy and safety of such dosing.
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Despite growing interest in the placebo effect, the neural correlates of conditioned analgesia are still incompletely understood. We investigated herein on brain activity during the conditioning and post-conditioning phases of a placebo experimental paradigm, using event-related fMRI in 31 healthy volunteers. Brief laser heat stimuli delivered to one foot (either right or left) were preceded by different visual cues, signalling either painful stimuli alone, or painful stimuli accompanied by a (sham) analgesic procedure. ⋯ Specifically, a large focus in the right prefrontal cortex showed activity related to analgesia, irrespective of the expected side of stimulation. Analgesia was also related to decreased activity, detectable immediately following noxious stimulation, in parietal, insular and cingulate pain-related clusters. Our findings of dynamic changes in prefrontal areas during placebo conditioning, and of direct placebo effects on cortical nociceptive processing, add new insights into the neural bases of conditioned placebo analgesia.
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Other people can have a significant impact on one's pain. Although correlational data abound, causal relationships between one's pain experience, individual traits of social relating (e.g. attachment style), and social factors (e.g. empathy) have not been investigated. Here, we studied whether the presence of others and 'perceived empathy' (defined as participants' knowledge of the extent to which observers felt they understood and shared their pain) can modulate subjective and autonomic responses to pain; and whether these influences can be explained by individual traits of pain coping and social attachment. ⋯ In addition, social presence decreased autonomic responses to pain irrespective of individual personality traits. To our knowledge this is the first time that adult attachment style has been shown to modulate the effects of social presence and 'perceived empathy' on experimentally induced pain. The results are discussed in relation to recent cognitive models of pain coping and attachment theory.
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Few studies have investigated whether prognostic indicators, which contribute to the transition from acute to chronic low back pain (LBP), are also those which contribute to continuing persistence of chronic LBP. We compared the contribution of physical, psychological and social indicators to predicting disability after one year between consulters with LBP of less than 3 months duration and more than 3 months duration. Data from two large prospective cohort studies of consecutive patients consulting with LBP in general practices were merged, providing complete data for 258 cases with acute/subacute LBP and 668 cases with chronic LBP at 12 months follow-up. ⋯ Fear of pain was significantly associated with disability in chronic LBP. Importantly, beyond baseline disability, the effect size of the other prognostic indicators for poor outcome was rather low. These findings must continue to challenge researchers to identify useful early predictors of outcome in persons with disabling back pain, as screening and targeted treatment approaches are dependent upon prognostic indicators with clinical significance.
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The present prospective longitudinal study on chronic postoperative pain was conducted to assess the predictive power of attentional and emotional variables specifically assumed to augment pain, such as pain hypervigilance, pain-related anxiety, pain catastrophizing and attentional biases to pain. Their relevance was determined in comparison with other psychological and physiological predictors (depression, anxiety, somatization, cortisol reactivity, pain sensitivity). In 84 young male patients the predictor variables were assessed one day before surgery (correction of chest malformation). ⋯ The few subjectively disabled patients after six months could be identified in addition by low pressure pain and high cold pain thresholds before surgery. An attentional bias towards positive stimuli prior to surgery may indicate a maladaptive coping style, which avoids necessary confrontation with pain and predisposes patients to chronic postoperative pain. Lasting subjectively felt pain-related disability occurs predominantly in patients with high levels of pain hypervigilance before surgery.