Pain
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Randomized Controlled Trial
Effects of Hypnosis vs Mindfulness Meditation vs Education on Chronic Pain Intensity and Secondary Outcomes in Veterans: A Randomized Clinical Trial.
Effective, rigorously evaluated nonpharmacological treatments for chronic pain are needed. This study compared the effectiveness of training in hypnosis (HYP) and mindfulness meditation (MM) with an active education control (ED). Veterans (N = 328) were randomly assigned to 8 manualized, group-based, in-person sessions of HYP (n = 110), MM (n = 108), or ED (n = 110). ⋯ No significant differences on outcomes between HYP and MM were detected at any time point. This study suggests that all 3 interventions provide posttreatment benefits on a range of outcomes, but the benefits of HYP and MM continue beyond the end of treatment, while the improvements associated with ED dissipate over time. Future research is needed to determine whether the between-group differences that emerged posttreatment are reliable, whether there are benefits of combining treatments, and to explore moderating and mediating factors.
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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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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.