Pain
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Randomized Controlled Trial
Partial reinforcement, extinction, and placebo analgesia.
Numerous studies indicate that placebo analgesia can be established via conditioning procedures. However, these studies have exclusively involved conditioning under continuous reinforcement. Thus, it is currently unknown whether placebo analgesia can be established under partial reinforcement and how durable any such effect would be. ⋯ However, although the placebo analgesia established under CRF extinguished during test phase, the placebo analgesia established under PRF did not. These findings indicate that PRF can induce placebo analgesia and that these effects are more resistant to extinction than those established via CRF. PRF may therefore reflect a novel way of enhancing clinical outcomes via the placebo effect.
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Multicenter Study
Genome-wide analysis of single nucleotide polymorphisms and copy number variants in fibromyalgia suggest a role for the central nervous system.
Fibromyalgia (FM) is a highly disabling syndrome defined by a low pain threshold and a permanent state of pain. The mechanisms explaining this complex disorder remain unclear, and its genetic factors have not yet been identified. With the aim of elucidating FM genetic susceptibility factors, we selected 313 FM cases having low comorbidities, and we genotyped them on the Illumina 1 million duo array. ⋯ They were followed up, and an intronic deletion in NRXN3 was demonstrated to be associated to female cases of FM with low levels of comorbidities (P=.021, odds ratio [95% confidence interval]=1.46 [1.05-2.04]). Both GWAS and aCGH results point to a role for the central nervous system in FM genetic susceptibility. If the proposed FM candidate genes were further validated in replication studies, this would highlight a neurocognitive involvement in agreement with latest reports.
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The current cross-sectional study examined child and adolescent pain severity in relation to various domains of school functioning and, in line with self-determination theory, the potentially protective role of perceived teacher support of child/adolescent autonomy and competence. Data from a large representative sample of Flemish school children and adolescents (N=10650; 50.8% boys; age range 10-21years; mean age=14.33) was collected as part of the World Health Organization (WHO) collaborative Health Behaviour in School-Aged Children (HBSC) survey. Child/adolescent pain severity was graded based on a pediatric pain classification system adapted from that of Von Korff et al. ⋯ However, the association between pain grade and school absenteeism was less pronounced when children perceived their teachers to be highly supportive of competence and autonomy. Furthermore, teacher support of competence appeared to buffer against the harmful effects of severe pain upon instances of bullying experiences at school. Future research directions and implications for school-based interventions are discussed.