Pain
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Best current estimates of neuropathic pain prevalence come from studies using screening tools detecting pain with probable neuropathic features; the proportion experiencing significant, long-term neuropathic pain, and the proportion not responding to standard treatment are unknown. These "refractory" cases are the most clinically important to detect, being the most severe, requiring specialist treatment. The aim of this study was to estimate the proportion of neuropathic pain in the population that is "refractory," and to quantify associated clinical and demographic features. ⋯ Graded categories of chronic pain with and without neuropathic characteristics were generated, incorporating the refractory criteria. Completed questionnaires were returned by 4451 individuals (response rate 47%); 399 had "chronic pain with neuropathic characteristics" (S-LANSS positive, 8.9% of the study sample); 215 (53.9%) also reported a positive relevant history ("Possible neuropathic pain"); and 98 (4.5% of all Chronic Pain) also reported an "adequate" trial of at least one neuropathic pain drug ("Treated possible neuropathic pain"). The most refractory cases were associated with dramatically poorer physical and mental health, lower pain self-efficacy, higher pain intensity and pain-related disability, and greater health care service use.
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The objective of this study was to examine the prevalence and patterns associated with past-year medical use, medical misuse, and nonmedical use of prescription opioids (NMUPO) among adolescents over a 2-year time period and to examine substance abuse, sleeping problems, and physical pain symptoms associated with these patterns of medical use, medical misuse, and NMUPO. A Web-based survey was self-administered by a longitudinal sample of 2050 middle and high school students in 2009-2010 (Year 1) and again in 2010-2011 (Year 2). The study was set in 2 southeastern Michigan school districts. ⋯ Multiple logistic regression analyses indicated that the odds of a positive screen for substance abuse in Year 2 were greater for adolescents who reported medical misuse or NMUPO for non-pain-relief motives in Year 1 compared with those who did not use prescription opioids. The findings indicate an increased risk for substance abuse among adolescents who report medical misuse or NMUPO for non-pain-relief motives over time. The findings have important clinical implications for interventions to reduce medical misuse and NMUPO among adolescents.
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Comparative Study
Noxious stimulation excites serotonergic neurons: a comparison between the lateral paragigantocellular reticular and the raphe magnus nuclei.
The present study was designed to record electrophysiological responses to graded noxious thermal stimuli of serotonergic and nonserotonergic neurons in the lateral paragigantocellular reticular (LPGi) and the raphe magnus (RMg) nuclei in rats. All of the neurons recorded were juxtacellularly filled with neurobiotin and identified with double immunofluorescent labeling for both neurobiotin and serotonin. Under halothane anesthesia (0.75%), noxious thermal stimuli ⩾48°C activated almost all (88%) of the serotonergic neurons located within the LPGi (n=16). ⋯ Recording of serotonergic neurons in the RMg (n=21) demonstrated that the proportion of strongly activated (>2spike/s) neurons (19% vs 59% for the LPGi) as well as the magnitude of the activation (2.1±0.4spike/s: mean of responses above the population median) to thermal noxious stimuli were significantly lower than in the LPGi (P<.05). Within the boundaries of both the LPGi and the RMg (B3 group), nonserotonergic neurons were also predominantly excited (75%) by noxious stimuli, and the resulting activation (7.9±1.2spike/s) was even greater than that of serotonergic neurons. Thermal noxious stimuli-induced activation of LPGi serotonergic cells probably plays a key role in serotonin-mediated modulations of cardiac baroreflex and transmission of nociceptive messages occurring under such intense noxious conditions.