Pain
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Randomized Controlled Trial
Pain response to cannabidiol in opioid-induced hyperalgesia, acute nociceptive pain, and allodynia using a model mimicking acute pain in healthy adults in a randomized trial (CANAB II).
Opioids in general and remifentanil in particular can induce hyperalgesia. Preclinical data suggest that cannabidiol might have the capacity to reduce opioid-induced hyperalgesia (OIH). Thus, we investigated the effect of oral cannabidiol on OIH in healthy volunteers using an established pain model. ⋯ Cannabidiol was well tolerated. We conclude that a high single-oral dose of 1600-mg cannabidiol is not effective in reducing OIH. Before excluding an effect of cannabidiol on OIH, research should focus on drug formulations enabling higher cannabidiol concentrations.
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Randomized Controlled Trial
How do placebo effects contribute to mindfulness-based analgesia? Probing acute pain effects and interactions using a randomized balanced placebo design.
Recent sham-controlled studies suggest placebo effects contribute to acute pain relief after mindfulness interventions. However, the specific effects of mindfulness processes and their interaction with placebo effects remain unclear. This study aimed to characterize the role of mindfulness and placebo processes underlying mindfulness-based pain attenuation. ⋯ These findings suggest a lack of specific effects of mindfulness and instruction on acute pain. Nonetheless, participants' expectancies and beliefs about the treatment they received did predict pain relief. Together with the overall improvement after any intervention, these findings suggest that expectancy and belief may play a stronger role in attenuating acute pain in novices following brief mindfulness interventions than the actual mindfulness-specific processes or instructions delivered.
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Musculoskeletal pain is a global health concern, and work-related psychosocial stress might be a potential contributing factor. This cross-sectional study investigates whether job stress is associated with chronic and widespread musculoskeletal pain in 2051 Brazilian active civil servants included in the Brazilian Longitudinal Study of Adult Health Musculoskeletal (ELSA-Brasil MSK). Job stress was assessed using the Effort-Reward Imbalance (ERI) questionnaire. ⋯ Chronic musculoskeletal pain according to body regions, especially generalized pain, was also associated with ERI domains effort (OR = 2.06; 95%CI = 1.33-3.21), overcommitment (OR = 3.44; 95%CI = 2.20-5.39), and effort-reward imbalance ratio (OR = 2.06; 95%CI = 1.30-3.27). Results reveal an association between job stress not only with CMP at any site but notably with the pain spread to other body sites or regions. Our findings suggest that lowering stress at work and discouraging overcommitment may help reduce the CMP burden, including reduction of CMP spread from one site or region of the body to another.
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Randomized Controlled Trial
Non-invasive vagus nerve stimulation modulates trigeminal but not somatosensory perception: functional evidence for a trigemino-vagal system in humans.
Noninvasive vagus nerve stimulation (nVNS) is effective in several types of headache disorders. We sought to unravel the mechanism of how nVNS exhibits this efficacy. This study used a randomized, single-blind, sham-controlled, crossover design and comprised 3 projects with 3 independent cohorts of healthy participants. ⋯ Heart rate variability parameters did not change after nVNS. Our results provide functional evidence of a long hypothesized functional trigemino-vagal system in humans and may explain why nVNS is effective in some headache disorders but not in somatic pain disorders. Because unilateral nVNS modulated the trigeminal thresholds bilaterally, this effect is probably indirect through a central top-down mechanism.
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We assessed the joint effects of back pain and mental health conditions on healthcare utilization and costs in a population-based sample of adults in Ontario. We included Ontario adult respondents of the Canadian Community Health Survey between 2003 and 2012, followed up to 2018 by linking survey data to administrative databases. Joint exposures were self-reported back pain and mental health conditions (fair/poor mental health, mood, and anxiety disorder). ⋯ There was no evidence of synergism for all-cause utilization or costs. Combined effects of back pain and mental health conditions on back pain-specific utilization or opioid prescription were greater than expected, with evidence of synergism. Health services targeting back pain and mental health conditions together may provide greater improvements in outcomes.