The journal of pain : official journal of the American Pain Society
-
Review Meta Analysis
Reward for pain. Hyperalgesia and allodynia induced by operant conditioning: systematic review and meta-analysis.
Learning processes have been discussed in the context of pain chronicity for decades. Particularly, operant conditioning has been used to experimentally induce and modulate pain in healthy humans. In this systematic review and meta-analysis, research findings on pain facilitation (hyperalgesic effect) and pain elicitation (allodynic effect) are evaluated. ⋯ PERSPECTIVE: Operant conditioning can be a mechanism of pain chronicity. All experimental studies investigating this hypothesis have been identified and summarized. It has been demonstrated that allodynic and hyperalgesic effects can be induced by operant conditioning.
-
Native Americans (NAs) have a higher prevalence of chronic pain than any other U. S. racial/ethnic group; however, little is known about the mechanisms for this pain disparity. This study used quantitative sensory testing to assess pain experience in healthy, pain-free adults (n = 137 NAs (87 female), n = 145 non-Hispanic whites (NHW; 68 female)) after painful electric, heat, cold, ischemic, and pressure stimuli. ⋯ This could place NAs at risk for future chronic pain and could ultimately lead to a vicious cycle that maintains pain (eg, pain → anxiety/catastrophizing → pain). PERSPECTIVE: NAs experienced heightened sensory, anxiety, and catastrophizing reactions in response to multiple pain stimuli. Given the potential for anxiety and catastrophic thoughts to amplify pain, this characteristic may place them at risk for pain disorders and could lead to a vicious cycle that maintains pain.
-
Among youth with chronic pain, elevated somatic symptoms across multiple body systems have been associated with greater emotional distress and functional disability and could represent poor adaptation to pain. The Children's Somatic Symptoms Inventory (formerly the Children's Somatization Inventory) is commonly used to assess somatic symptoms in children. However, no studies have evaluated the clinical usefulness of the measure in the assessment of pediatric patients with chronic pain. ⋯ The assessment of somatic symptoms in pediatric patients with chronic pain may provide useful information regarding patients' psychosocial risk and tendency to access health services. Perspective: Clinical reference points based on the CSSI-24 total scores meaningfully differentiated youth with chronic pain on measures of emotional distress, functioning, parent catastrophizing and protective responses, and health care use. Assessing somatic symptoms could provide useful information regarding a pediatric patient's psychosocial risk, tendency to access health services, and need for enhanced care coordination.
-
Sphingosine-1-phosphate (S1P) receptor 1 subtype (S1PR1) activation by its ligand S1P in the dorsal horn of the spinal cord causes mechanohypersensitivity. The cellular and molecular pathways remain poorly understood. We report that the activation of S1PR1 with an intrathecal injection of the highly selective S1PR1 agonist SEW2871 led to the development of mechanoallodynia by activating the nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome (increased expression of NLRP3, cleaved caspase 1 and mature IL-1β) in the dorsal horn of the spinal cord. ⋯ Our findings provide novel mechanistic insights on how S1PR1 activation in the spinal cord contributes to the development of nociception while identifying the cellular substrate for these activities. PERSPECTIVE: This study is the first to link the activation of NLRP3 and IL-1β signaling in the spinal cord and S1PR1 signaling in astrocytes to the development of S1PR1-evoked mechanoallodynia. These findings provide critical basic science insights to support the development of therapies targeted toward S1PR1.
-
This study aims to determine the rate of chronic pain in a community sample of young adult cannabis users, assess the extent to which pain relief is an important motivation for cannabis use, and explore differences in consumption patterns and problem behaviors between users with and without chronic pain. The study design was cross-sectional. Self-selected community-dwelling young adults (ages 18-29 years; n = 143) who regularly use cannabis completed an online survey. ⋯ Cannabis users with and without chronic pain report experiencing several negative consequences owing to their use. PERSPECTIVE: This article compares motivations for cannabis use and describes differences in consumption patterns among a community sample of young adult users with and without chronic pain. This information may be useful for providers who assess and treat pain in young adults, particularly in settings that have legalized recreational use.