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N-3 fatty acids, including docosahexaenoic acid (DHA), have a beneficial effect in both pain and psychiatric disorders. In fact, we previously reported that stress-induced pain prolongation might be mediated through the suppression of the G-protein coupled-receptor 40/free fatty acid receptor 1 (GPR40/FFAR1), which is activated by DHA and long-chain fatty acids. However, the involvement of GPR40/FFAR1 ligands in the development of stress-induced chronic pain has not yet been described. In this study, we investigated the role of DHA in stress-evoked pain chronicity using diet-induced n-3 fatty acid deficient mice. The n-3 fatty acid deficient mice showed exacerbation of anxiety-like behavior after repeated exposure to social defeat stress. The intact n-3 fatty acid deficient mice showed a decrease in paw threshold values. On the other hand, paw withdrawal thresholds of defeated but not non-stressed, n-3 fatty acid deficient mice continued until day 49 after paw surgery. We evaluated changes in phosphatidylcholine composition in the brains of repeat stress-evoked chronic pain model mice which were not on n-3 fatty acid deficiency diets On day 7 after paw surgery, phosphatidylcholines with DHA and other long-chain fatty acids were found to have decreased in the brains of stressed mice. Moreover, stress-induced persistent mechanical allodynia was improved by oral DHA supplementation. These results indicated that chronic stress may directly affect brain lipid composition; the related changes could be involved in chronic pain development. Our findings suggested that n-3 fatty acids, particularly DHA, are useful as a potential therapeutic target for stress-evoked chronic pain.
Learn More >When patients first develop a painful temporomandibular disorder (TMD) and seek care, 1 priority for clinicians is to assess prognosis. The authors aimed to develop a predictive model by using biopsychosocial measures from the Diagnostic Criteria for Temporomandibular Disorders (DC-TMD) to predict risk of developing TMD symptom persistence.
Learn More >Co-prevalence of chronic pain and post-traumatic stress disorder (PTSD) negatively impacts the course of both disorders. Patients diagnosed with both conditions report greater pain, affective distress and disability when compared to those with either chronic pain or PTSD alone. While the prevalence and complexity of the comorbidity is widely acknowledged, there is a dearth of research examining potential mechanism variables that might account for the relationship between chronic pain and PTSD. The current study utilizes a series of mediation analyses to examine if pain catastrophizing mediates the relationship between PTSD symptomatology and chronic pain outcome.
Learn More >Sleep disturbance and chronic pain are related. The present study evaluated both direct and indirect (mediated) pathways through which sleep disturbance might be related to chronic pain intensity and function.
Learn More >Internalizing mental health issues co-occur with pediatric chronic pain at high rates and are linked to worse pain and functioning. Although the field has prioritized anxiety and posttraumatic stress disorder, little is known about co-occurring depression and chronic pain in youth, despite its high prevalence. The purpose of this narrative review was to examine the existing literature on the co-occurrence of pediatric chronic pain and depressive disorders and symptoms and propose a conceptual model of mutual maintenance to guide future research.
Learn More >The conceptualization of placebo has changed from inactive pills to a detailed understanding of how patients' perception of receiving a treatment influences pain processing and overall treatment outcome. Large placebo effects were recently demonstrated in chronic neuropathic pain, thereby opening the question of whether placebo effects also apply to orofacial neuropathic pain. In this article, we review the new definitions, magnitude, and social, psychological, neurobiologic, and genetic mechanisms of placebo effects in pain, especially neuropathic pain, to illustrate that placebo effects are not simply response bias but psychoneurobiological phenomena that can be measured at many levels of the neuroaxis. We use this knowledge to carefully illustrate how patients' perceptions of the treatment, the relationship with the health care provider, and the expectations and emotions toward a treatment can influence test and treatment outcome and potentially skew the results if they are not taken into consideration. Orofacial neuropathic pain is a new research area, and we review the status on definition, diagnosis, mechanisms, and pharmacologic treatment of neuropathic pain after trigeminal nerve injury, as this condition may be especially influenced by placebo factors. Finally, we have a detailed discussion of how knowledge of placebo mechanisms may help improve the understanding, diagnosis, and treatment of orofacial neuropathic pain, and we illustrate pitfalls and opportunities of applying this knowledge to the test of dental treatments.
Learn More >Treatment options for chronic low back pain (CLBP) include cognitive behavioral interventions. Most of these interventions only have small and short-lived effects. Using strict inclusion criteria for participation in an intensive combined physical and psychological program, encouraging effects were reported at 1-year follow-up. This study evaluates the long-term follow-up results of the same program. The hypothesis is that previously reported results are maintained.
Learn More >To investigate whether physician-patient agreement of potential patient problem areas impacts subsequent patient enrollment in an interdisciplinary pain management program.
Learn More >This systematic review summarises evidence assessing endogenous pain inhibition in people with irritable bowel syndrome (IBS) compared with healthy controls using conditioned pain modulation (CPM) and offset analgesia (OA). Evidence regarding the role of psychological variables is also examined. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Four electronic databases were searched to retrieve studies assessing CPM or OA in adults diagnosed with IBS according to the ROME II/III criteria. Standardized mean differences were calculated for each study and a random effects model was used for meta-analysis. Eleven studies were included, 5 of which reported results on the relationship between CPM and psychological variables. None of the studies assessed OA. The risk of bias assessment found a lack of assessor blinding in all studies. The pooled effect estimate was 0.90 (95% CI, 0.40-1.40) indicating a significantly lower CPM effect in people with IBS compared with controls. This effect was reduced to 0.51 when 1 outlier was excluded from the analysis. In addition, reduced CPM responses were significantly correlated with higher anxiety (r=0.17 to 0.64), stress (r=0.63), and pain catastrophizing (r=0.38) in people with IBS; however, the evidence available was limited and the strength of these associations variable. Depression was not found to be associated with CPM in these IBS cohorts. The results of this review suggest that people with IBS, as a group, demonstrate reduced pain inhibition measured by CPM. The preliminary evidence about the association between psychological factors and CPM warrants further investigations.
Learn More >Parents play a critical role in children's experience of, and recovery from, chronic pain. Although several parental factors have been linked to child pain and functioning, these factors are typically examined in isolation or as moderators/mediators. Structural equation modeling affords the opportunity to examine the extent to which parental factors are interrelated, and if there are differential associations among parental factors and child outcomes. Based on extant literature, a unified model of parental factors, including chronic pain status, physical functioning, responses to child pain, and psychological factors, and their effect on child pain and functioning, was conceptualized. This model was evaluated using structural equation modeling based on data from 146 dyads recruited from a multidisciplinary pain clinic. Modifications to model iterations were made based on theoretical and statistical justification. The final model revealed associations among all parental factors with significant loadings on child pain and functioning. Findings indicated the conceptual model was supported, with the exception of parent responses to child pain. Findings support inclusion of parent chronic pain status and physical and psychological functioning as part of a comprehensive assessment of youth with chronic pain and may inform new parental intervention targets to improve child outcomes. Perspective: A unified structural equation model indicated parents' own chronic pain characteristics and physical and psychological functioning represent important factors associated with child pain and functioning. Current family-based interventions which often primarily focus on parent responses to child pain may need to be adapted to more comprehensively address parental factors.
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