The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
The association of single nucleotide polymorphisms in the catechol-O-methyltransferase gene and pain scores in female patients with major depressive disorder.
We tested the hypothesis that single nucleotide polymorphisms (SNPs) in the catechol-O-methyltransferase (COMT) gene are associated with baseline pain levels in patients with major depressive disorder (MDD). Pain levels were quantified using a visual analog scale (VAS) for pain. Data from 159 female and 93 male self-reported white patients with MDD were analyzed. The associations between a haplotype previously associated with pain sensitivity created using COMT SNPs rs6269, rs4633, rs4818, and rs4680, and the proportion of female patients with "Pain While Awake" and "Overall Pain" at baseline were statistically significant (P < .05). In male patients, no statistically significant associations between COMT haplotypes and baseline pain scores were seen. The rs165599 SNP, which has previously been associated with response of depressive symptoms to treatment in patients with MDD, did not impact baseline pain in either gender. In conclusion, baseline pain levels appear to be associated with the COMT pain sensitivity haplotype in female patients with MDD. ⋯ This article presents associations of the COMT pain sensitivity haplotype and baseline pain levels in female patients with MDD. This finding could potentially help clinicians who seek to assess how genetic polymorphisms may contribute to a patient's pain experience.
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Randomized Controlled Trial
Ginger (Zingiber officinale) reduces muscle pain caused by eccentric exercise.
Ginger has been shown to exert anti-inflammatory effects in rodents, but its effect on human muscle pain is uncertain. Heat treatment of ginger has been suggested to enhance its hypoalgesic effects. The purpose of this study was to examine the effects of 11 days of raw (study 1) and heat-treated (study 2) ginger supplementation on muscle pain. Study 1 and 2 were identical double-blind, placebo controlled, randomized experiments with 34 and 40 volunteers, respectively. Participants consumed 2 grams of either raw (study 1) or heated (study 2) ginger or placebo for 11 consecutive days. Participants performed 18 eccentric actions of the elbow flexors to induce pain and inflammation. Pain intensity, perceived effort, plasma prostaglandin E(2), arm volume, range-of-motion and isometric strength were assessed prior to and for 3 days after exercise. Results Raw (25%, -.78 SD, P = .041) and heat-treated (23%, -.57 SD, P = .049) ginger resulted in similar pain reductions 24 hours after eccentric exercise compared to placebo. Smaller effects were noted between both types of ginger and placebo on other measures. Daily supplementation with ginger reduced muscle pain caused by eccentric exercise, and this effect was not enhanced by heat treating the ginger. ⋯ This study demonstrates that daily consumption of raw and heat-treated ginger resulted in moderate-to-large reductions in muscle pain following exercise-induced muscle injury. Our findings agree with those showing hypoalgesic effects of ginger in osteoarthritis patients and further demonstrate ginger's effectiveness as a pain reliever.
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Randomized Controlled Trial
High levels of vicarious exposure bias pain judgments.
The present study evaluated the effects of exposure to facial expression of pain, on observers' perceptions of pain expression. Participants were undergraduates shown brief video clips of the facial expressions of shoulder-pain patients displaying no pain or moderate pain. Participants were randomly allocated to either a high preexposure condition in which each clip was preceded by 10 other clips showing strong pain or a no-exposure control. On each test trial, participants indicated whether they thought the person they saw was in pain or not. Data were analyzed using signal detection theory methods. High prior exposure to pain was unrelated to sensitivity to pain expression, but did significantly diminish the likelihood of judging the other to be in pain. Results are discussed in terms of their implications for pain judgments of health-care professionals, adaptation-level theory, and the psychophysical method of selective adaptation. ⋯ This paper provides an experimental demonstration that, when people have large amounts of exposure to others' expressions of pain, their estimation of others' pain is reduced. The findings offer 1 explanation for the widely observed underestimation bias in pain judgments and may suggest ways of changing it.