Sex differences in the efficacy of psychological therapies for the management of chronic and recurrent pain in children and adolescents: a systematic review and meta-analysis

Sex, gender, and pain: Evidence and knowledge gaps

Sex and gender contribute to the variation in pain experience. A range of biological, psychological, and social factors are relevant, which point to potential pain mechanisms and the reasons for this sex/gender-based variation. This review provides a brief critical overview of the evidence for these patterns. It draws on both experimental and clinical studies and identifies some of the biological and psychosocial factors that are thought to impact on men and women's pain. There are limitations and gaps in understanding, and numerous challenges exist, ranging from difficulties with concepts through to methodology. There is a focus on gender as a dimensional set of psychosocial constructs, as this offers one approach to help enhance our understanding of men and women's pain.

The effects of autistic traits in adolescents on the efficacy of paediatric Intensive Interdisciplinary Pain Treatment (IIPT)

Autistic adolescents are at greater risk of chronic pain, but it is unclear how autistic features may relate to individual aspects of chronic pain. As autism traits exist in the general population as well, it is important to know if autistic traits could impact how effective chronic pain management is for adolescents. Here we examined autistic traits in 112 patients (12-18yrs) recruited from a UK national specialist adolescent pain rehabilitation programme. Participants completed screening questionnaires for autistic traits upon entry to the programme, as well as clinically recognised pain measures before and after the 3-week treatment program. Autistic traits predicted greater psychological challenges at treatment onset. Critically, autistic traits were not related to the magnitude of improvement in pain measures during the pain management program. Our study suggests that adolescents with greater autistic traits may benefit from existing pain rehabilitation programs at similar rates to their peers. Additionally, these data suggest no reason for therapeutic pessimism for autistic pain patients. We do however acknowledge that these data may differ in populations with an autistic diagnosis, and that barriers may still exist for autistic people in treatment for pain. PERSPECTIVE: Autistic traits were explored in patients undergoing an Intensive Interdisciplinary Pain Treatment (IIPT). Higher autistic traits correlated with more pain related psychological difficulties at intake. Autistic traits were not related to the magnitude of improvement following IIPT. Our data therefore suggests that autism should not be a barrier to IIPT. DATA AVAILABILITY: Data is held in the PAIRED Pain Rehabilitation Database: Bath and Bristol, individual data used in the current analyses are therefore not available.

Pain and development: interacting phenomena

ABSTRACT

For decades, clinicians and researchers have observed bidirectional relationships between child development and the pain experience in childhood. Pain in childhood is an inherently developmental phenomenon, embedded in an iterative, time-dependent process that reflects individual biological, behavioral, social, psychological, and environmental characteristics that unfold across the early life span. Childhood pain can have wide ranging effects on brain development in ways that contribute-for better and worse-to social, emotional, and cognitive well-being in childhood and on into adulthood. Atypical trajectories of development in the context of disorders such as autism, cerebral palsy, ADHD, and mood/anxiety disorders also contribute to unique childhood pain experiences. In this paper, pain will be considered as a determinant of development, and conversely development will be considered as a key determinant of a child's pain experience. We will discuss how intersectional identities (eg, gender, race, socioeconomic status) and associated social, structural, systemic, and physical environments influence the relationship between development and pain. Finally, we will identify what might be needed to think "developmentally" in ways that extend from the "bench side" in the lab to the "curb side" in the community, integrating a developmental perspective into research and clinical practice to achieve health accessibility and equity in pain care for all children across the developmental spectrum.

Selenoprotein T, a potential treatment of attention-deficit/hyperactivity disorder and comorbid pain in neonatal 6-OHDA lesioned mice

pathological pain and Attention-deficit/hyperactivity disorder (ADHD) are two complex multifactorial syndromes. The comorbidity of ADHD and altered pain perception is well documented in children, adolescents, and adults. According to pathophysiological investigations, the dopaminergic system's dysfunction provides a common basis for ADHD and comorbid pain. Growing evidence suggests that oxidative stress may be crucial in both pathologies. Recent studies revealed that a small peptide encompassing the redox-active site of selenoprotein T (PSELT), protects dopaminergic neurons and fibers as well as lesioned nerves in animal models. The current study aims to examine the effects of PSELT treatment on ADHD-like symptoms and pain sensitivity, as well as the role of catecholaminergic systems in these effects. Our results demonstrated that intranasal administration of PSELT reduced the hyperactivity in the open field, decreased the impulsivity displayed by 6-OHDA-lesioned male mice in the 5-choice serial reaction time task test and improved attentional performance. In addition, PSELT treatment significantly increased the nociception threshold in both normal and inflammatory conditions. Furthermore, anti-hyperalgesic activity was antagonized with sulpiride pre-treatment, but not by phentolamine, or propranolol pre-treatments. The present study suggests that PSELT reduces the severity of ADHD symptoms in mice and possesses potent antinociceptive effects which could be related to the involvement of D2/D3 dopaminergic receptors.

Prevalence of chronic and multisite pain in adolescents and young adults with ADHD: a comparative study between clinical and general population samples (the HUNT study)

Attention-deficit/hyperactivity disorder (ADHD) and chronic pain are prevalent and associated. We examined the prevalence and distribution of chronic pain in adolescents and young adults with ADHD using 9-years longitudinal data (from T1:2009-2011 to T3:2018-2019) with three time points from a clinical health survey compared to two age-matched reference population-based samples. Mixed-effect logistic regression and binary linear regression were used to estimate the probability for chronic and multisite pain at each time point and to compare the prevalence of chronic pain with the reference populations. The prevalence of chronic and multisite pain was high in those with ADHD, especially in female young adults, with highly prevalent chronic pain at 9 years of follow-up (75.9%) compared to 45.7% in females in the reference population. The probability of having pain was only statistically significant for chronic pain in males at 3 years of follow-up (41.9%, p = 0.021). Those with ADHD were at higher risk of reporting single-site and multisite pain compared to the general population at all measurement points. Longitudinal studies should be tailored to further understand the complex sex differences of comorbid chronic pain and ADHD in adolescents, exploring predictive factors of pain assessing long-term associations with bodyweight, psychiatric comorbidities, and possible mechanisms of stimulant use effects on pain.

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

Challenges with embedding an integrated sex and gender perspective into pain research: Recommendations and opportunities

The focus of this article, within this BBI horizons special issue, is on sex, gender, and pain. We summarise what is currently known about sex- and gender-related variations in pain, exploring intersectional biological and psychosocial mechanisms, and highlight gaps in knowledge and understanding. Five key challenges with the exploration of sex and gender in pain research are presented, relating to: conceptual imprecision, research bias, limitations with binary descriptions, integrating sex and gender, and timely adoption/implementation of good research practice. Guidance on how to overcome such challenges is provided. Despite clear evidence for sex and gender differences in pain, there are conceptual and methodological barriers to overcome. Innovation in methods and approach can help develop more effective and tailored treatment approaches for men, women, boys, girls, and gender-diverse people.

Topical Review: Acute and Chronic Pain Experiences in Transgender and Gender-Diverse Youth

OBJECTIVE

To provide an overview of the existing literature on gender diversity in pediatric acute and chronic pain, propose an ecological systems model of understanding pain in transgender and gender-diverse (TGD) youth, and identify a direction for future work that will address the key knowledge gaps identified.

METHODS

Relevant literature on pain and gender diversity was reviewed, drawing from adult literature where there was insufficient evidence in pediatric populations. Existing relevant models for understanding minority stress, gender and pain, and pain experiences within marginalized groups were considered with the reviewed literature to develop a pain model in TGD youth.

RESULTS

While there is an abundance of literature pointing to increased risk for pain experiences amongst TGD youth, there is comparably little empirical evidence of the rates of pain amongst TGD youth, prevalence of TGD identities in pain care settings, effective pain treatments for TGD youth and unique considerations for their care, and the role intersectional factors in understanding TGD youth identities and pain.

CONCLUSION

Pediatric psychologists are well-positioned to advance the research on acute and chronic pain in TGD youth, make evidence-based adaptations to clinical care for TGD youth with pain, including pain related to gender affirmation, and support colleagues within the medical system to provide more inclusive care.

Associations between Chronic Pain and Attention-Deficit Hyperactivity Disorder (ADHD) in Youth: A Scoping Review

Background: Chronic pain and ADHD are common conditions among youth that negatively impact functioning. This review fills a critical gap by summarizing current research on chronic pain and ADHD comorbidity, and it proposes a conceptual model of shared associations and underlying mechanisms. Objective: The aims of the current study were to: (1) review the extant literature and present estimates of the prevalence of comorbid non-headache chronic pain and ADHD in youth and (2) describe potential shared mechanisms for ADHD and chronic non-headache pain in youth. We also outline future directions to inform future research and interventions directed to youth with comorbid pain and ADHD. Design: A scoping review of the literature was performed in MEDLINE, PsycInfo, and Cochrane Database of Systematic Reviews using a wide range of search terms related to pain, Attention Deficit-Hyperactivity Disorder, childhood, adolescence, and young adulthood. Results: Eleven published studies were included in the review. These studies examined the prevalence of chronic pain among youth with ADHD, the prevalence of ADHD in chronic pain samples, and the association between chronic pain and ADHD among youth. Findings revealed results from studies indicating a higher prevalence of ADHD among youth with chronic pain and a higher prevalence of chronic pain in samples of youth with ADHD. Conclusions: Findings from this scoping review suggest an association between chronic pain and ADHD among youth. Little research was found to examine the etiology of this association. Future studies should examine underlying mechanisms of comorbid chronic pain and ADHD.

Data visualization as an intervention for pediatric chronic pain: a pilot feasibility study protocol for a randomized controlled crossover trial

BACKGROUND

Chronic pain is a common and costly condition in youth, associated with negative implications that reach far beyond the pain experience itself (e.g., interference with recreational, social, and academic activities, mental health sequelae). As a self-appraised condition, pain experience is influenced by patient's biases and meaning-making in relation to their symptoms and triggers. We propose that interacting with self-reported data will impact the experience of pain by altering understanding and expectations of symptom experience and how pain interacts with other factors (e.g., sleep, emotions, social interactions). In this study, we aim to establish the feasibility and acceptability of using a data visualization platform to track and monitor symptoms and their relationship with other factors, versus simply daily reporting of symptoms using a smartphone-based Ecological Momentary Assessment (EMA).

METHODS

This protocol is for a randomized, single-center, open-label crossover trial. We aim to recruit 50 typically developing youth aged 12-18 years with chronic pain to take part in two phases of data collection. The trial will utilize an A-B counterbalanced design in which participants will be randomly assigned to receive either Part A (EMA alone for 7 days) or Part B (EMA plus visualization platform for 7 days) first and then receive the opposite phase after a 7-day break (washout period). Key outcomes will be participant reports of acceptability and feasibility, EMA completion rates, barriers, and perceptions of the benefits or risks of participation. Secondary exploratory analyses will examine the relationship between EMA-reported symptoms over time and in relation to baseline measures, as well as pilot data on any improvements in symptoms related to engaging with the data visualization platform.

DISCUSSION

This protocol describes the feasibility and pilot testing of a novel approach to promoting self-management and facilitating symptom appraisal using visualized data. We aim to determine whether there is a sufficient rationale, both from the perspective of feasibility and patient satisfaction/acceptability, to conduct a larger randomized controlled trial of this intervention. This intervention has the potential to support clinical care for youth with chronic pain and other conditions where self-appraisal and understanding of symptom patterns are a critical component of functional recovery.

TRIAL REGISTRATION

Open Science Framework doi: https://doi.org/10.17605/OSF.IO/HQX7C . Registered on October 25, 2021, osf.io/hqx7c.

Pediatric Chronic Orofacial Pain: A Narrative Review of Biopsychosocial Associations and Treatment Approaches

Pediatric chronic orofacial pain (OFP) is an umbrella term which refers to pain associated with the hard and soft tissues of the head, face, and neck lasting >3 months in patients younger than 18 years of age. Common chronic pediatric OFP diagnoses include temporomandibular disorder, headaches, and neuropathic pain. Chronic OFP can adversely affect youth's daily functioning and development in many areas of well-being, and may be associated with emotional stress, depression, functional avoidance, and poor sleep, among other negative outcomes. In this mini-review, we will discuss common psychological comorbidities and familial factors that often accompany chronic pediatric OFP conditions. We will also discuss traditional management approaches for pediatric orofacial pain including education, occlusal appliances, and psychological treatments such as relaxation, mindfulness-based interventions, and cognitive-behavioral treatments. Finally, we highlight avenues for future research, as a better understanding of chronic OFP comorbidities in childhood has the potential to prevent long-term pain-related disability in adulthood.

Pediatric Chronic Pain, Resilience and Psychiatric Comorbidity in Canada: A Retrospective, Comparative Analysis

Objective

Chronic pain compromises child and adolescent well-being and development. This study aimed to identify risk factors for chronic pain and exploration of how young people negotiate such risks and express resilience. We hypothesized children and youth with chronic pain would report greater prevalence of mental health disorders than the general population; and those demonstrating greater resilience would demonstrate less psychiatric comorbidity.

Method

A retrospective chart review was conducted for all patients (ages 7-17) attending the sole pediatric chronic pain clinic in Manitoba, from 2015 to 2019 (N = 116). Patients' demographic information and psychiatric illness burden were compared to provincial epidemiological data using Chi-Square tests. Pain sites, family history, psychiatric illness, psychosocial functioning, treatment history and treatment recommendations were explored.

Results

The sample was predominantly female (74%; N = 114). Sixty-eight percent of patients reported a family history of chronic pain. Thirty-seven percent of the patients (vs. 14.0% anticipated; N = 326 260) reported comorbid psychiatric disorder, X² (1, N = 114) = 53.00, p < 0.001. Thirty-two percent reported diagnosis of mood and/or anxiety disorder (vs. 7.3%), X² (1, N = 114) = 99.34, p < 0.001. Children and youth demonstrating resilience through engagement in more prosocial behaviors reported fewer psychiatric symptoms (rs = -0.292, N = 114, p = 0.002, Spearman's correlation).

Conclusions

Female sex, family history, and lower socioeconomic status were associated with chronic pain. Psychiatric conditions were more prevalent in chronic pain patients than in the general population. Approaching chronic pain from a mind-body perspective, while building on patients' strengths, is central to informing treatment.

The anatomy of pain and suffering in the brain and its clinical implications

Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause of human suffering worldwide, because effective, specific and safe therapies have yet to be developed. It is unevenly distributed among sexes, with women experiencing more pain and suffering. Chronic pain can be anatomically and phenomenologically dissected into three separable but interacting pathways, a lateral 'painfulness' pathway, a medial 'suffering' pathway and a descending pain inhibitory pathway. One may have pain(fullness) without suffering and suffering without pain(fullness). Pain sensation leads to suffering via a cognitive, emotional and autonomic processing, and is expressed as anger, fear, frustration, anxiety and depression. The medial pathway overlaps with the salience and stress networks, explaining that behavioural relevance or meaning determines the suffering associated with painfulness. Genetic and epigenetic influences trigger chronic neuroinflammatory changes which are involved in transitioning from acute to chronic pain. Based on the concept of the Bayesian brain, pain (and suffering) can be regarded as the consequence of an imbalance between the two ascending and the descending pain inhibitory pathways under control of the reward system. The therapeutic clinical implications of this simple pain model are obvious. After categorizing the working mechanisms of each of the available treatments (pain killers, psychopharmacology, psychotherapy, neuromodulation, psychosurgery, spinal cord stimulation) to 1 or more of the 3 pathways, a rational combination can be proposed of activating the descending pain inhibitory pathway in combination with inhibition of the medial and lateral pathway, so as to rebalance the pain (and suffering) pathways.

Do Children With Functional Abdominal Pain Benefit More From a Pain-Specific Cognitive-Behavioral Intervention Than From an Unspecific Attention Control Intervention? Results of a Randomized Controlled Trial

INTRODUCTION

We aimed to compare the efficacy of cognitive-behavioral therapy (CBT) among children with functional abdominal pain with an attention control (AC), hypothesizing the superiority of CBT group intervention regarding pain intensity (primary outcome), pain duration and frequency (further primary outcomes), functional disability, and quality of life and coping strategies (key secondary outcomes).

METHODS

We conducted a prospective, multicenter, randomized controlled efficacy trial (RCT) with 4 time points (before intervention, after intervention, 3-month follow-up, and 12-month follow-up). One hundred twenty-seven children aged 7-12 years were randomized to either the CBT (n = 63; 55.6% girls) or the AC (n = 64; 57.8% girls).

RESULTS

Primary endpoint analysis of the logarithmized area under the pain intensity curve showed no significant difference between groups (mean reduction = 49.04%, 95% confidence interval [CI] -19.98%-78.36%). Treatment success rates were comparable (adjusted odds ratio = 0.53, 95% CI 0.21-1.34, number needed to treat = 16). However, time trend analyses over the course of 1 year revealed a significantly greater reduction in pain intensity (40.9%, 95% CI 2.7%-64.1%) and pain duration (43.6%, 95% CI 6.2%-66.1%) in the CBT compared with the AC, but not in pain frequency per day (1.2, 95% CI -2.7 to 5.2). In the long term, children in the CBT benefitted slightly more than those in the AC with respect to functional disability, quality of life, and coping strategies.

DISCUSSION

Both interventions were effective, which underlines the role of time and attention for treatment efficacy. However, in the longer term, CBT yielded more favorable results.

Phenotyping peripheral neuropathic pain in male and female adolescents: pain descriptors, somatosensory profiles, conditioned pain modulation, and child-parent reported disability

ABSTRACT

Neuropathic pain (NeuP) can be difficult to diagnose and manage in children. Data regarding prevalence and sex-dependent differences are limited, and more detailed phenotyping is needed. This observational cohort study recruited adolescents (10-17 years) with NeuP or complex regional pain syndrome (CRPS). After pain history and NeuP questionnaires, quantitative sensory testing was performed. Individual z-score plots were calculated with body-region control measures and matched to mechanism-related sensory profiles (sensory loss, thermal hyperalgesia, and mechanical hyperalgesia). Conditioned pain modulation was assessed with pressure pain threshold and a contralateral cold conditioning stimulus, and meaningful conditioned pain modulation defined as twice the standard error of measurement. Patients and parents completed validated questionnaires for child quality of life (QoL), pain catastrophizing, and self-reported anxiety/depression. Males (n = 23) and females (n = 43) with NeuP (n = 52) or CRPS (n = 14) reported moderate-severe pain with neuropathic sensory descriptors. Mixed patterns of sensory gain/loss at pain sites were not sex-dependent. Thermal hyperalgesia was common in both NeuP and CRPS, whereas sensory loss occurred only with NeuP and in a smaller proportion than adult cohorts. Conditioned pain modulation was inhibitory in 54%, facilitatory in 14%, and nonresponders had variable cold conditioning sensitivity. Males and females reported marked impairment of QoL, increased emotional distress, and pain catastrophising. Child-parent QoL scores correlated, but catastrophizing scores were discordant when parents or adolescents reported higher anxiety/depression. NeuP in adolescents is associated with significant pain, physical impairment, and psychosocial impairment. Quantifying alterations in somatosensory profiles, descending modulation, child and parent psychological function will inform individualized therapy and stratification for future clinical trials.

The gender context of pain

Pain is a major source of global suffering, with women bearing the greatest burden. Alongside biology, psychological and social factors, including gender, help explain these differences. However, there has been no direct attempt to develop a unified social psychological model of men and women's pain. By drawing on approaches to both gender and pain, a gender context model of pain is presented. It proposes that pain is partly influenced by the gender context in which it occurs, which operates at both individual and interpersonal levels. The model is used to structure an appraisal of the existing evidence around gender and pain, and explore whether the model helps explain why such variation occurs. It is argued that despite evidence for an association between gender and pain, there are empirical gaps that need to be addressed. Implications and directions for future investigations into sex, gender and pain are considered.

Reporting and analyses of sex/gender and race/ethnicity in randomized controlled trials of interventions published in the highest-ranking anesthesiology journals

Aim: We assessed reporting of data on sex/gender and race/ethnicity in randomized controlled trials of interventions published in the highest-ranking anesthesiology journals from 2014 to 2017. Methods: We extracted data regarding terminology for sex/gender, proportion of participants according to the race/gender and race/ethnicity, and results shown for the race/gender and race/ethnicity. Results: Among the analyzed 732 trials, few stratified allocation of participants on the basis of sex/gender and race/ethnicity, few reported results for sex/gender or race/ethnicity and the outcomes reported may be influenced by one or both. Conclusion: In conclusion, outcomes of anesthesiology trials could be vulnerable to an important and avoidable source of bias; trialists need to pay more attention to sex and race/ethnicity when designing and reporting their studies.

Exploring the relationship between male norm beliefs, pain-related beliefs and behaviours: An online questionnaire study

BACKGROUND

Gender beliefs help explain the variation found in pain among men and women. Gender norms and expectations are thought to affect how men and women report and express pain. However, less is known about how such beliefs are related to pain outside of laboratory settings. The aim of this study was therefore to consider the relationship between beliefs in male role norms, pain and pain behaviours in men and women.

METHODS

An online questionnaire study was conducted. A total of 468 adults (352 women), with or without pain, completed a series of self-report measures relating to beliefs about pain and male role norms, as well as pain and general health behaviours.

RESULTS

An experience of pain was associated with lower beliefs in traditional male norms. Endorsing stereotypical male norms was related to increased stigma associated with seeking professional help for pain in both men and women, but to a lesser extent associated with general health behaviours. There also seemed to be gender-based beliefs associated with the expression of pain.

CONCLUSIONS

Together these findings suggest that beliefs in gender (male) norms are relevant to pain, and that there is utility in exploring the variation in pain beyond binary male-female categories.

Nociceptive mechanisms involved in the acute and chronic phases of a complex regional pain syndrome type 1 model in mice

Complex regional pain syndrome I (CRPS-I) is a chronic painful pathology still undertreated. CTK 01512-2 is a recombinant version of the spider peptide Phα1β, and it functions as a voltage-gated calcium channel blocker and a transient receptor potential ankyrin 1 (TRPA1) antagonist with antinociceptive effect in different pain models. Here, we investigate the mechanisms involved in the acute and chronic nociceptive phases of a model of CPRS-I in mice and assess the antinociceptive effect of CTK 01512-2 using this model. Adult male and female mice C57BL/6 (20-30 g) were used to determine mechanical (von Frey test) or cold (acetone test) allodynia induction. Inflammatory parameters (serum and tibial nerve lactate levels, hind paw temperature and edema, or tissue cell infiltration) were evaluated after chronic post-ischemia pain (CPIP, a model of CPRS-I) induction. Anti-inflammatory and anti-neuropathic drugs or CTK 01512-2 were tested. First, we detected that CPIP-induced mechanical and cold allodynia in male and female mice in a similar way. In the acute phase (1 day after CPIP), an increase in inflammatory parameters were observed, as well as the anti-allodynic effect of anti-inflammatory compounds. In the chronic phase (17 days after CPIP), mice exhibited mechanical and cold allodynia, and anti-neuropathic drugs induced antinociception, while no inflammatory alterations were found. CTK 01512-2 reversed the CPIP allodynic effect in both nociceptive phases. Thus, this CPRS-I model can be used to understand the mechanisms involved in CPRS-I induced pain and inflammation. Besides, we observed that CTK 01512-2 has a valuable antinociceptive effect in this pain model.

TRPV1 Channel Contributes to the Behavioral Hypersensitivity in a Rat Model of Complex Regional Pain Syndrome Type 1

Complex regional pain syndrome type 1 (CRPS-I) is a debilitating pain condition that significantly affects life quality of patients. It remains a clinically challenging condition and the mechanisms of CRPS-I have not been fully elucidated. Here, we investigated the involvement of TRPV1, a non-selective cation channel important for integrating various painful stimuli, in an animal model of CRPS-I. A rat model of chronic post-ischemia pain (CPIP) was established to mimic CRPS-I. TRPV1 expression was significantly increased in hind paw tissue and small to medium-sized dorsal root ganglion (DRG) neurons of CPIP rats. CPIP rats showed increased TRPV1 current density and capsaicin responding rate in small-sized nociceptive DRG neurons. Local pharmacological blockage of TRPV1 with the specific antagonist AMG9810, at a dosage that does not produce hyperthermia or affect thermal perception or locomotor activity, effectively attenuated thermal and mechanical hypersensitivity in bilateral hind paws of CPIP rats and reduced the hyperexcitability of DRG neurons induced by CPIP. CPIP rats showed bilateral spinal astrocyte and microglia activations, which were significantly attenuated by AMG9810 treatment. These findings identified an important role of TRPV1 in mediating thermal and mechanical hypersensitivity in a CRPS-I animal model and further suggest local pharmacological blocking TRPV1 may represent an effective approach to ameliorate CRPS-I.

Intergenerational examination of pain and posttraumatic stress disorder symptoms among youth with chronic pain and their parents

Introduction

Posttraumatic stress disorder (PTSD) symptoms are prevalent among youth with chronic pain, and associated with poorer pain outcomes and health-related quality of life (HRQoL). Conceptual models suggest that parent factors, including parents' own chronic pain, may be linked to higher co-occurring pain and PTSD symptoms and lower HRQoL in children. However, this has not been empirically examined.

Objectives

The aim of this study was to examine the relationship between parental chronic pain and (1) parent PTSD symptoms, (2) child PTSD symptoms, (3) child pain outcomes, and (4) child HRQoL in a sample of treatment-seeking youth with chronic pain and their parents.

Methods

Youth (n = 173) aged 8 to 18 years and parents (n = 204) recruited from a tertiary-level pediatric chronic pain program completed psychometrically-sound measures of pain and PTSD symptoms. Youth also completed measures of pain interference and HRQoL.

Results

Half of the parents in this sample reported chronic pain. A series of analyses of covariances revealed that parents with vs without chronic pain reported significantly higher PTSD symptoms, and children of parents with vs without chronic pain reported significantly higher PTSD symptoms and pain interference and lower HRQoL.

Conclusion

Findings from this study suggest that having a parent with chronic pain may confer additional risk for children with chronic pain experiencing higher PTSD symptoms, poorer pain outcomes, and lower HRQoL than having a parent without chronic pain. This could be due to genetics or social learning. Future longitudinal research is needed to understand how parental pain influences co-occurring pain and PTSD symptoms, and HRQoL, in children.

The Pivotal Role of Pediatric Psychology in Chronic Pain: Opportunities for Informing and Promoting New Research and Intervention in a Shifting Healthcare Landscape

PURPOSE OF REVIEW

In the context of new efforts to formulate more comprehensive diagnostic and treatment processes for chronic pain conditions, this review aims to provide an overview of some of the most salient developments in the diagnosis and clinical treatment of pediatric chronic pain and to delineate the current and future role of clinical pediatric psychologists in these efforts.

RECENT FINDINGS

The acceptance and promotion of the multidisciplinary approach to pediatric pain management has had an especially significant impact on the field of pediatric psychology. Though chronic pain was historically conceptualized as a biomedical problem, psychology is increasingly viewed as a routine, integral, and component part of treatment. With this evolving biopsychosocial paradigm, pediatric psychology is poised to help shape the development of this field, contributing to emerging conceptual and diagnostic frameworks via consultation, research, clinical care, and education. This review discusses the role of pediatric psychologists as collaborators in emerging diagnostic and assessment frameworks, leaders in pain-related research, drivers of clinical care, and educators for providers, patients, and the lay public. With increased opportunities to enhance the conceptualization and treatment of pediatric pain, pediatric psychologists have an important role to play in reducing the prevalence and persistence of pediatric pain.

Gender disparity in pediatrics: a review of the current literature

BACKGROUND

Gender-based medicine is an innovative branch of biomedical research and represents a new perspective for the future of health research. Many studies have been published on gender medicine in adults but very few data regarding children are available.

LITERATURE SEARCH AND RESULTS

A literature search covering articles published between 1stJuly, 2006 and 1st February, 2017 and concerning children only was conducted using multiple keywords and standardized terminology in Pubmed database. The search was limited to English-language publications. All relevant articles on endocrines, neurological, psychiatric, gastrointestinal, immunological, oncological, rheumatic, pneumological disorders, infectious diseases and analgesia were evaluated and pertinent articles were included in this review. Most of the available studies on gender disparity in childhood are about endocrine and neuro-psychiatric disorders, while there are few data in other areas of medicine.

CONCLUSIONS

Even if several studies on pediatric gender differences can be found on literature, few of them move forwards to analyze the reasons of the observed diversity. No data on pharmacokinetic and pharmacodynamic differences between boys and girls can be found. Hence, more efforts should be directed to investigate these topics in childhood.

Social interaction and pain: An arctic expedition

Complex human behaviour can only be understood within its social environment. However, disentangling the causal links between individual outcomes and social network position is empirically challenging. We present a research design in a closed real-world setting with high-resolution temporal data to understand this interplay within a fundamental human experience - physical pain. Study participants completed an isolated 3-week hiking expedition in the Arctic Circle during which they were subject to the same variation in environmental conditions and only interacted amongst themselves. Adolescents provided daily ratings of pain and social interaction partners. Using longitudinal network models, we analyze the interplay between social network position and the experience of pain. Specifically, we test whether experiencing pain is linked to decreasing popularity (increasing isolation), whether adolescents prefer to interact with others experiencing similar pain (homophily), and whether participants are increasingly likely to report similar pain as their interaction partners (contagion). We find that reporting pain is associated with decreasing popularity - interestingly, this effect holds for males only. Further exploratory analyses suggest this is at least partly driven by males withdrawing from contact with females when in pain, enhancing our understanding of pain and masculinity. Contrary to recent experimental and clinical studies, we found no evidence of pain homophily or contagion in the expedition group.

Sex differences in complex regional pain syndrome type I (CRPS-I) in mice

BACKGROUND

Sex differences have been increasingly highlighted in complex regional pain syndrome (CRPS) in clinical practice. In CRPS type I (CRPS-I), although inflammation and oxidative stress have been implicated in its pathogenesis, whether pain behavior and the underlying mechanism are sex-specific is unclear. In the present study, we sought to explore whether sex differences have an impact on inflammation, oxidative stress, and pain sensitivity in CRPS-I.

METHODS

Chronic post-ischemia pain (CPIP) was established in both male and female mice as an animal model of CRPS-I. Edema and mechanical allodynia of bilateral hind paws were assessed after reperfusion. Blood samples were analyzed for serum levels of oxidative stress markers and inflammatory cytokines.

RESULTS

Both male and female mice developed edema. Male mice developed CPIP at day 3 after reperfusion; female mice developed CPIP at day 2 after reperfusion. Female mice displayed significantly earlier and higher mechanical allodynia in the ischemic hind paw, which was associated with higher serum levels of IL-2, TNF-α, isoprostanes, 8 OhdG, and malondialdehyde at day 2 after reperfusion. Moreover, female mice showed significantly lower SOD and IL-4 compared to male mice at day 2 after reperfusion.

CONCLUSION

Our results indicate that sex differences in inflammatory and oxidative stress states may play a central role in the sex-specific nociceptive hypersensitivity in CRPS-I, and offer a new insight into pharmacology treatments to improve pain management with CRPS.

Advancing psychological therapies for chronic pain

There is a strong tradition of therapy development and evaluation in the field of psychological interventions for chronic pain. However, despite this research production, the effects of treatments remain uncertain, and treatment development has stalled. This review summarises the current evidence but focusses on promising areas for improvement. Advancing psychological therapies for chronic pain will come from a radical re-imagining of the content, delivery, place, and control of therapy. The next generation of therapeutic interventions will also need alternative methods of measurement and evaluation, and options are discussed.