Genetic correlations between pain phenotypes and depression and neuroticism

The association of pain phenotype and providing caregiving with depressive symptom trajectory for older adults: a longitudinal analysis using the health and retirement study

BACKGROUND

This study aims to analyze the association between different pain phenotypes and depressive symptom trajectory among community-dwelling older adults, and whether and how providing caregiving render older adults with pain more prone to a deteriorating depressive trajectory.

METHODS

Data were derived from the Health and Retirement Study between 2008 and 2020. Older adults were classified into different pain phenotypes leveraging four pain characteristics at baseline (i.e. 2008) using latent class analysis, including pain intensity, pain interference, pain location, and pain persistence. Caregiving status was collected at baseline using helper lists. Depressive symptoms were measured biennially from 2008 to 2020. Linear mixed models were constructed to explore the independent and interacted effects of pain phenotypes and providing caregiving on depressive symptom trajectory.

RESULTS

Among 8486 participants aged 60 years old or over (58.8% females, and mean age of 74.28), four pain phenotypes were identified: Severe-persistent pain group (15.0%), Moderate pain group (17.3%), Back pain group (7.0%), and Pain-free group (60.7%). Compared to the Pain-free group, other three pain subtypes exhibited higher baseline depression symptoms with a gradient trend. Older adults with Severe-persistent pain had a significantly slower rate of depression symptom increase. Caregiving did not moderate the impact of any pain subtype on baseline depression symptoms, but it significantly reduced the rate of increase in depression symptoms for both Severe-persistent pain group and Back pain group.

CONCLUSIONS

Pain phenotype-informed depression services should be delivered. Promoting the caregiving benefit finding for the elderly would contribute to the remission of depressive symptom.

The inflammatory and genetic mechanisms underlying the cumulative effect of co-occurring pain conditions on depression

Chronic pain conditions frequently coexist and share common genetic vulnerabilities. Despite evidence showing associations between pain and depression, the additive effect of co-occurring pain conditions on depression risk and the underlying mechanisms remain unclear. Leveraging data from 431,038 UK Biobank participants with 14-year follow-up, we found a significantly increased risk of depression incidence in individuals reporting pain, irrespective of body site or duration (acute or chronic), compared with pain-free individuals. The depression risk increased with the number of co-occurring pain sites. Mendelian randomization supported potential causal inference. We constructed a composite pain score by combining individual effects of acute or chronic pain conditions across eight body sites in a weighted manner. We found that depression risks increased monotonically in parallel with composite pain scores. Moreover, some inflammatory markers, including C-reactive protein, partially mediated the association between composite pain scores and depression risk. Considering the high prevalence of comorbid depression and pain, pain screening may help identify high-risk individuals for depression.

Artificially Sweetened Food Mediates the Perception of Chronic Pain in Individuals With Neuroticism Traits: A Mendelian Randomization Study

BACKGROUND

Previous studies have shown that neuroticism and artificially sweetened food all play essential roles in chronic pain to varying degrees. However, it is unclear precisely the causal relationship between neuroticism traits and chronic pain and whether an unhealthy sweetened food is a mediator in this process.

METHODS

This study employed rigorous research methods to ensure the validity of the findings. We utilized Mendelian randomization (MR) to examine the causal relationships between neuroticism traits, artificially sweetened food, and chronic pain. The data encompass four neuroticism traits (neuroticism, experiencing mood swings, depressed affect, and worry), consumption levels of nine artificially sweetened foods, and seven types of chronic pain. The primary statistical method employed was inverse variance weighting (IVW). Eventually, we explored whether artificially sweetened food serves as a mediator in the relationship between neuroticism traits and chronic pain.

RESULTS

We found that genetic predisposition to higher neuroticism traits and the consumption of artificial sweeteners is associated with an increased risk of chronic pain across multiple sites. Reverse MR analysis also confirms that chronic pain at multiple sites similarly increases the risk of neuroticism traits. Two-step MR suggests the mediating effects of five artificial sweeteners on sciatica: low back pain, thoracic pain, low back pain, joint pain, and muscular pain. These findings could inform interventions and treatments for chronic pain.

CONCLUSION

Neuroticism traits and chronic pain have causal relationships, with artificially sweetened food mediating the pathway from neuroticism traits to chronic pain.

Genome-wide by trait interaction analyses with neuroticism reveal chronic pain-associated depression as a distinct genetic subtype

The frequent co-occurrence of chronic pain (CP) and depression is a well-known phenomenon, supported by both the high prevalence of major depression among CP patients and studies describing a substantial genetic correlation between the two phenotypes. Neuroticism, a trait characterised by maladaptive stress responses and a tendency to experience negative emotions, has been linked to both depression and the experience of pain. This study aimed to determine whether depression associated with CP represents a genetically distinct subtype and to explore the role of neuroticism in modulating genetic susceptibility to depression. To address these questions, we performed genome-wide association analyses for current depression utilising the UK Biobank dataset, followed by genome-wide by trait interaction analyses to assess the interaction effect of neuroticism, and polygenic risk score analyses to compare predictions. Our findings suggest that CP-related depression is a valid subtype of depression. In association with current depression, we identified a total of 49 novel genetic risk polymorphisms meeting the genome-wide significance threshold, including variants involved in synaptic plasticity and transcriptional regulation. Additionally, our results support that neuroticism has a prominent role in modulating the genetic risk of current depression independently of CP, which highlights the importance of considering personality traits and stress factors in understanding the genetic background of complex and heterogeneous phenotypes like depression.

Associations between childhood maltreatment and personality traits in individuals with and without depression: a CTQ-based assessment

BACKGROUND

Prior research has established a correlation between childhood maltreatment (CM) and personality traits. The current understanding regarding the potential variability in the relationship between CM and its impact on personality dimensions among those with major depressive disorder (MDD) and healthy controls (HCs) remains elusive.

AIMS

This study analyzes the association between CM and personality traits in the MDD and HC groups.

METHODS

The study recruited 188 individuals with MDD and 132 HC. The Childhood Trauma Questionnaire (CTQ) was used to assess CM, and the Sixteen Personality Factor Questionnaire (16PF) was used to assess personality traits. We used a 2*2 analysis of covariance (ANCOVA) of the diagnosis and CM on 16PF, and hierarchical regression explored the association between specific types of CM and 16PF in both groups.

RESULTS

The 2*2 ANCOVA results indicated significant interaction effects between CM and diagnosis on personality traits, with CM's impact notably different between groups. In the MDD group, sexual abuse (SA) independently predicted the subscale Q1 (Openness to Change), related to the Big Five's openness. In the HC group, emotional abuse (EA) predicted the subscales C (emotional stability), O (apprehension), and Q4(tension), linked to Big Five's neuroticism.

CONCLUSION

The findings highlight the impact of early adversity on personality development, informing psychology and guiding tailored therapy development.

The influence of credits and stigmas in volunteering on depression, the modulating effects of volunteer personality and motivation

Depression is a common mental health issue affecting volunteers, which directly impacts the quality of services they provide. This study investigates the unique aspects of volunteer depression and analyzes the roles of volunteer credits, stigmatization, personality traits, and motivations in influencing depression levels. Data were collected from a survey of 822 volunteers from the Red Cross in Hubei Province, China. The results indicate that higher volunteer credits significantly reduced depression scores, while increased stigmatization was associated with higher depression levels. Personality traits such as agreeableness and conscientiousness helped mitigate the negative effects of stigmatization, while openness exacerbated its impact. Furthermore, volunteers driven by understanding and value expression were more susceptible to the adverse effects of stigmatization. The findings highlight the importance of improving volunteer mental health by enhancing team trust and reducing stigmatization. Although the large sample size strengthens the study, the cross-sectional design limits causal inference. Overall, the study underscores the importance of understanding personality traits and motivations in developing effective volunteer support measures, thereby enhancing service quality and community well-being.

A genome-wide association study identifies genetic variants associated with hip pain in the UK Biobank cohort (N = 221,127)

Hip pain is a common musculoskeletal complaint that leads many people to seek medical attention. We conducted a primary genome-wide association study (GWAS) on the hip pain phenotype within the UK Biobank cohort. Sex-stratified GWAS analysis approach was also performed to explore sex specific variants associated with hip pain. We found seven different loci associated with hip pain at GWAS significance level, with the most significant single nucleotide polymorphism (SNP) being rs77641763 within the EXD3 (p value = 2.20 × 10-13). We utilized summary statistics from the FinnGen cohort and a previous GWAS meta-analysis on hip osteoarthritis as replication cohorts. Four loci (rs509345, rs73581564, rs9597759, rs2018384) were replicated with a p value less than 0.05. Sex-stratified GWAS analyses revealed a unique locus within the CUL1 gene (rs4726995, p = 2.56 × 10-9) in males, and three unique loci in females: rs1651359966 on chromosome 7 (p = 1.15 × 10-8), rs552965738 on chromosome 9 (p = 2.72 × 10-8), and rs1978969 on chromosome 13 (p = 2.87 × 10-9). This study has identified seven genetic loci associated with hip pain. Sex-stratified analysis also revealed sex specific variants associated with hip pain in males and females. This study has provided a foundation for advancing research of hip pain and hip osteoarthritis.

Chronic pain is specifically associated with updating working memory: a longitudinal twin study

ABSTRACT

Worse executive function (EF) is associated with chronic pain and could mechanistically contribute to pain chronification. It is unclear whether there is overall impairment in EFs or whether there are impairments in specific cognitive domains. Furthermore, the possible genetic risk underlying these associations has not been tested. Participants were from the Colorado Longitudinal Twin study; 786 same-sex twins completed a battery of EF tasks at ages 23 and/or 28 and 634 of these twins self-reported chronic pain at mean age = 28.1; prevalence = 27.76% using the Brief Pain History Questionnaire. The EF tasks were used to define a Common EF factor and 2 factors specific to updating working memory and shifting mental set. We estimated the phenotypic and genetic associations of stable EF variance across ages 23 and 28, as well as EF variance unique to age 28, with pain. With respect to stable EF variance, pain phenotypically correlated with the Updating-specific factor ( r = -0.21, P = 0.008) but did not significantly correlate with the Common EF factor ( r = -0.06, P = 0.350) nor with the Shifting-specific factor ( r = -0.03, P = 0.709). There were no significant phenotypic correlations between pain and EF variance unique to age 28. A twin model indicated that pain and Updating-specific variance share genetic risk ( r A = -0.46, P = 0.005) but not environmental risk ( r E = 0.05, P = 0.844). Updating working memory shares a phenotypic and genetic relationship with pain in young adults. Impairments in gating or monitoring pain signals may play a mechanistic role in pain development.

Unpacking the relationship between Big Five personality traits and experimental pain: A systematic review and meta-analysis

Pain is essential for survival, but individual responses to painful stimuli vary, representing a complex interplay between sensory, cognitive, and affective factors. Individual differences in personality traits and in pain perception covary but it is unclear which traits play the most significant role in understanding the pain experience and whether this depends on pain modality. A systematic search identified 1534 records (CINAHL, MEDLINE, PsycInfo, PubMed and Web of Science), of which 22 were retained and included in a systematic review. Only studies from the pressure pain domain (n=6) could be compared in a formal meta-analysis to evaluate the relationship between Big Five traits and experimental pain. Pressure pain tolerance correlated positively with Extraversion and negatively with Neuroticism with a trivial effect size (<0.1). While these findings suggest personality might be only weakly related to pain in healthy individuals, we emphasize the need to consider standardization, biases, and adequate sample sizes in future research, as well as additional factors that might affect experimental pain sensitivity.

Identification of Oxidative Stress-Related Biomarkers for Pain-Depression Comorbidity Based on Bioinformatics

Oxidative stress has been identified as a major factor in the development and progression of pain and psychiatric disorders, but the underlying biomarkers and molecular signaling pathways remain unclear. This study aims to identify oxidative stress-related biomarkers and signaling pathways in pain-depression comorbidity. Integrated bioinformatics analyses were applied to identify key genes by comparing pain-depression comorbidity-related genes and oxidative stress-related genes. A total of 580 differentially expressed genes and 35 differentially expressed oxidative stress-related genes (DEOSGs) were identified. By using a weighted gene co-expression network analysis and a protein-protein interaction network, 43 key genes and 5 hub genes were screened out, respectively. DEOSGs were enriched in biological processes and signaling pathways related to oxidative stress and inflammation. The five hub genes, RNF24, MGAM, FOS, and TKT, were deemed potential diagnostic and prognostic markers for patients with pain-depression comorbidity. These genes may serve as valuable targets for further research and may aid in the development of early diagnosis, prevention strategies, and pharmacotherapy tools for this particular patient population.

Communicating pain: emerging axonal signaling in peripheral neuropathic pain

Peripheral nerve damage often leads to the onset of neuropathic pain (NeuP). This condition afflicts millions of people, significantly burdening healthcare systems and putting strain on families' financial well-being. Here, we will focus on the role of peripheral sensory neurons, specifically the Dorsal Root Ganglia neurons (DRG neurons) in the development of NeuP. After axotomy, DRG neurons activate regenerative signals of axons-soma communication to promote a gene program that activates an axonal branching and elongation processes. The results of a neuronal morphological cytoskeleton change are not always associated with functional recovery. Moreover, any axonal miss-targeting may contribute to NeuP development. In this review, we will explore the epidemiology of NeuP and its molecular causes at the level of the peripheral nervous system and the target organs, with major focus on the neuronal cross-talk between intrinsic and extrinsic factors. Specifically, we will describe how failures in the neuronal regenerative program can exacerbate NeuP.

Association of chronic pain with suicide attempt and death by suicide: a two-sample Mendelian randomization

Prior studies have suggested an association between chronic pain and suicidal behavior. However, evidence supporting the causal nature of this association, and the role played by depression, remain difficult to establish due to confounding. We investigated associations of chronic pain with suicide attempt and death by suicide as well as the mediating role of depression in this association using a genetically informed method strengthening causal inference. We conducted a two-sample Mendelian randomization. Independent SNPs (N = 97) from the multisite chronic pain GWAS (NGWAS = 387,649) were used as instrumental variables to test associations of chronic pain with suicide attempt (measured from hospital records; NGWAS = 50,264) and death by suicide (measured from official death causes; NGWAS = 18,085). Indirect associations of chronic pain with suicide attempt and death by suicide via major depressive disorder (NGWAS = 173,005) were estimated. Primary analyses were supported by a range of sensitivity and outlier analyses. We found evidence supporting the contribution of chronic pain to increasing the risk of suicide attempt (OR = 1.67, CI = 1.21-2.35) and death by suicide (OR = 2.00, CI = 1.10-3.62). Associations were consistent across sensitivity analysis methods, and no evidence for outliers driving these associations was found. Through mediation analyses, we found that major depressive disorder explained a substantial proportion of the association between chronic pain and suicide attempt (proportion mediated = 39%; ORindirect association = 1.32, CI = 1.09-1.61) and death by suicide (proportion mediated = 34%; ORindirect association = 1.40, CI = 1.13-1.73). Our findings suggest that both pain management interventions and prevention of depression are likely to be effective strategies to reduce suicide risk in individuals with chronic pain.

Personality and Pain Outcomes in Rheumatic Disease: The Mediating Role of Psychological Flexibility

BACKGROUND

Chronic pain is associated with increased disability and vulnerability to emotional disorders. Personality and psychological flexibility (PF) describe interindividual differences that shape the adjustment to chronic pain. Specifically, PF was found to be associated with pain, fatigue, anxiety, and depression intensity. Although previous studies established strong correlations between personality and pain outcomes, evidence on the nature of this relationship is scarce. Therefore, the objective of this study is to explore the mediating effect of PF on the relationship between personality and distress.

METHODS

This transversal study included 108 participants (age M = 56.7, SD = 11.3) diagnosed with musculoskeletal chronic pain. Self-reported measures were administered by the medical care team. Multiple mediation models were performed for estimating the indirect effects on each outcome variable.

RESULTS

After controlling for age and gender covariates, we found that PF completely mediated the relationship between personality traits and all pain outcomes and partially mediated the impact of extraversion on anxiety. In addition, emotional stability also had an indirect effect on anxiety through PF.

CONCLUSIONS

Personality traits and PF are significant predictors of pain outcomes. PF represents a core process mediating the impact of personality traits on the perceived intensity of pain, fatigue, anxiety, and depression in patients with rheumatic disease. These results could facilitate the application of individualized psychological interventions in clinical contexts targeting the reduction of emotional avoidance and in chronic pain patients.

Pain site persistence and changes from childhood to adolescence: a prospective cohort study

BACKGROUND

Pain is a complex experience that interferes with the well-being of youth who experience it. We aimed to assess whether recurrent pain sites in childhood can predict later recurrent pain sites prospectively.

METHODS

Pain was assessed using the Luebeck Pain Screening Questionnaire at ages 7, 10, and 13 from the Generation XXI cohort. We used multinomial regression to assess the association of recurrent pain sites at ages 7 and 10 with those at age 13.

RESULTS

We included 3833 participants. Boys with recurrent abdominal/pelvic pain at age 7 were more likely to report headaches (OR 2.81; 95%CI 1.48-5.34), abdominal/pelvic (OR 2.92; 95%CI 1.46-5.84), and musculoskeletal pain (OR 1.55; 95%CI 1.02-2.34) at age 13. Girls with recurrent abdominal/pelvic pain at age 7 were more likely to report both musculoskeletal (OR 1.62; 95%CI 1.10-2.40) and abdominal/pelvic pain (OR 1.74; 95%CI 1.15-2.65). At age 10, all pain sites were associated with pain in the same site at age 13.

CONCLUSION

Recurrent abdominal/pelvic pain at age 7 may be related to the development of various pains in adolescence. Pain at a given site at age 10 can be associated with pain at that same site at age 13.

IMPACT

Recurrent abdominal or pelvic pain during childhood was distinctively associated with an increased risk of recurrent pain in other sites during adolescence. Recurrent pain during childhood was associated with pain in the same sites at age 13, and this persistence seemed to emerge between the ages of 7 and 10 for both boys and girls. Studying early pain sites may add to the understanding of the etiology of chronic pain.

Variability in the prevalence of depression among adults with chronic pain: UK Biobank analysis through clinical prediction models

BACKGROUND

The prevalence of depression among people with chronic pain remains unclear due to the heterogeneity of study samples and definitions of depression. We aimed to identify sources of variation in the prevalence of depression among people with chronic pain and generate clinical prediction models to estimate the probability of depression among individuals with chronic pain.

METHODS

Participants were from the UK Biobank. The primary outcome was a "lifetime" history of depression. The model's performance was evaluated using discrimination (optimism-corrected C statistic) and calibration (calibration plot).

RESULTS

Analyses included 24,405 patients with chronic pain (mean age 64.1 years). Among participants with chronic widespread pain, the prevalence of having a "lifetime" history of depression was 45.7% and varied (25.0-66.7%) depending on patient characteristics. The final clinical prediction model (optimism-corrected C statistic: 0.66; good calibration on the calibration plot) included age, BMI, smoking status, physical activity, socioeconomic status, gender, history of asthma, history of heart failure, and history of peripheral artery disease. Among participants with chronic regional pain, the prevalence of having a "lifetime" history of depression was 30.2% and varied (21.4-70.6%) depending on patient characteristics. The final clinical prediction model (optimism-corrected C statistic: 0.65; good calibration on the calibration plot) included age, gender, nature of pain, smoking status, regular opioid use, history of asthma, pain location that bothers you most, and BMI.

CONCLUSIONS

There was substantial variability in the prevalence of depression among patients with chronic pain. Clinically relevant factors were selected to develop prediction models. Clinicians can use these models to assess patients' treatment needs. These predictors are convenient to collect during daily practice, making it easy for busy clinicians to use them.

A multi-ancestry genetic study of pain intensity in 598,339 veterans

Chronic pain is a common problem, with more than one-fifth of adult Americans reporting pain daily or on most days. It adversely affects the quality of life and imposes substantial personal and economic costs. Efforts to treat chronic pain using opioids had a central role in precipitating the opioid crisis. Despite an estimated heritability of 25-50%, the genetic architecture of chronic pain is not well-characterized, in part because studies have largely been limited to samples of European ancestry. To help address this knowledge gap, we conducted a cross-ancestry meta-analysis of pain intensity in 598,339 participants in the Million Veteran Program, which identified 126 independent genetic loci, 69 of which are new. Pain intensity was genetically correlated with other pain phenotypes, level of substance use and substance use disorders, other psychiatric traits, education level and cognitive traits. Integration of the genome-wide association studies findings with functional genomics data shows enrichment for putatively causal genes (n = 142) and proteins (n = 14) expressed in brain tissues, specifically in GABAergic neurons. Drug repurposing analysis identified anticonvulsants, β-blockers and calcium-channel blockers, among other drug groups, as having potential analgesic effects. Our results provide insights into key molecular contributors to the experience of pain and highlight attractive drug targets.

The multi-generational familial aggregation of interstitial cystitis, other chronic nociplastic pain disorders, depression, and panic disorder

BACKGROUND

Interstitial cystitis/painful bladder syndrome (IC) is a chronic pelvic pain condition which has high comorbidity with other nociplastic, or unexplained, pain disorders [e.g. fibromyalgia (FM), irritable bowel syndrome (IBS), and myalgic encephalomyelitis/chronic fatigue (ME/CFS)] and some psychiatric conditions [major depressive disorder (MDD) and panic disorder (PD)]. Here we investigated the shared familiality of IC and these other nociplastic and psychiatric conditions.

METHODS

Subjects were identified in the Utah Population Database, which links genealogy data back to the 1800s to medical record diagnosis billing code data back to 1995. We computed the relative risk of each of these disorders among first (FDR), second (SDR), and third-degree relatives (TDR) of six proband groups: IC, FM, IBS, ME/CFS, PD, and MDD. Given the known familial aggregation of each of these disorders, we conducted our analyses to test for heritable interrelationships using proband subgroups whose members did not have the diagnosis assessed in their relatives.

RESULTS

We observed strong evidence for heritable interrelationships among all six disorders. Most analyses indicated significantly increased risk for each of the six disorders in FDR, SDR, and TDR of all or most proband groups. Out of 30 possible bidirectional disorder interrelationships, 26 were significant among FDR, 23 were significant among SDR, and 7 were significant among TDR. Clustering was observed in both close and distant relatives.

CONCLUSIONS

Our results support a common, heritable component to IC and other nociplastic and psychiatric conditions.

Genome-wide association study on pharmacological outcomes of musculoskeletal pain in UK Biobank

The pharmacological management of musculoskeletal pain starts with NSAIDs, followed by weak or strong opioids until the pain is under control. However, the treatment outcome is usually unsatisfying due to inter-individual differences. To investigate the genetic component of treatment outcome differences, we performed a genome-wide association study (GWAS) in ~23,000 participants with musculoskeletal pain from the UK Biobank. NSAID vs. opioid users were compared as a reflection of the treatment outcome of NSAIDs. We identified one genome-wide significant hit in chromosome 4 (rs549224715, P = 3.88 × 10-8). Suggestive significant (P < 1 × 10-6) loci were functionally annotated to 18 target genes, including four genes linked to neuropathic pain processes or musculoskeletal development. Pathway and network analyses identified immunity-related processes and a (putative) central role of EGFR. However, this study should be viewed as a first step to elucidate the genetic background of musculoskeletal pain treatment.

Big data, big consortia, and pain: UK Biobank, PAINSTORM, and DOLORisk

Chronic pain (CP) is a common and often debilitating disorder that has major social and economic impacts. A subset of patients develop CP that significantly interferes with their activities of daily living and requires a high level of healthcare support. The challenge for treating physicians is in preventing the onset of refractory CP or effectively managing existing pain. To be able to do this, it is necessary to understand the risk factors, both genetic and environmental, for the onset of CP and response to treatment, as well as the pathogenesis of the disorder, which is highly heterogenous. However, studies of CP, particularly pain with neuropathic characteristics, have been hindered by a lack of consensus on phenotyping and data collection, making comparisons difficult. Furthermore, existing cohorts have suffered from small sample sizes meaning that analyses, especially genome-wide association studies, are insufficiently powered. The key to overcoming these issues is through the creation of large consortia such as DOLORisk and PAINSTORM and biorepositories, such as UK Biobank, where a common approach can be taken to CP phenotyping, which allows harmonisation across different cohorts and in turn increased study power. This review describes the approach that was used for studying neuropathic pain in DOLORisk and how this has informed current projects such as PAINSTORM, the rephenotyping of UK Biobank, and other endeavours. Moreover, an overview is provided of the outputs from these studies and the lessons learnt for future projects.

The interplay of personality traits, anxiety, and depression in Chinese college students: a network analysis

Background

Anxiety and depression are among the greatest contributors to the global burden of diseases. The close associations of personality traits with anxiety and depression have been widely described. However, the common practice of sum scores in previous studies limits the understanding of the fine-grained connections between different personality traits and anxiety and depression symptoms and cannot explore and compare the risk or protective effects of personality traits on anxiety and depression symptoms.

Objective

We aimed to determine the fine-grained connections between different personality traits and anxiety and depression symptoms and identify the detrimental or protective effects of different personality traits on anxiety and depression symptoms.

Methods

A total of 536 college students from China were recruited online, and the average age was 19.98 ± 1.11. The Chinese version of the Ten-Item Personality Inventory, Generalized Anxiety Disorder-7, and Patient Health Questionnaire-9 was used to investigate the personality traits and symptoms of anxiety and depression of participants after they understood the purpose and filling method of the survey and signed the informed consent. The demographic characteristics were summarized, and the scale scores were calculated. The network model of personality traits and symptoms of anxiety and depression was constructed, and bridge expected influence (BEI) was measured to evaluate the effect of personality traits on anxiety and depression. The edge accuracy and BEI stability were estimated, and the BEI difference and the edge weight difference were tested.

Results

In the network, 29 edges (indicating partial correlations between variables) bridged the personality community and the anxiety and depression community, among which the strongest correlations were extraversion-fatigue, agreeableness-suicidal ideation, conscientiousness-uncontrollable worry, neuroticism-excessive worry, neuroticism-irritability, and openness-feelings of worthlessness. Neuroticism had the highest positive BEI value (0.32), agreeableness had the highest negative BEI value (-0.27), and the BEI values of neuroticism and agreeableness were significantly different from those of most other nodes (p < 0.05).

Conclusion

There are intricate correlations between personality traits and the symptoms of anxiety and depression in college students. Neuroticism was identified as the most crucial risk trait for depression and anxiety symptoms, while agreeableness was the most central protective trait.

Neurophysiological and Psychosocial Mechanisms of Fibromyalgia: A Comprehensive Review and Call for An Integrative Model

Research into the neurobiological and psychosocial mechanisms involved in fibromyalgia has progressed remarkably in recent years. Despite this, current accounts of fibromyalgia fail to capture the complex, dynamic, and mutual crosstalk between neurophysiological and psychosocial domains. We conducted a comprehensive review of the existing literature in order to: a) synthesize current knowledge on fibromyalgia; b) explore and highlight multi-level links and pathways between different systems; and c) build bridges connecting disparate perspectives. An extensive panel of international experts in neurophysiological and psychosocial aspects of fibromyalgia discussed the collected evidence and progressively refined and conceptualized its interpretation. This work constitutes an essential step towards the development of a model capable of integrating the main factors implicated in fibromyalgia into a single, unified construct which appears indispensable to foster the understanding, assessment, and intervention for fibromyalgia.

Gender difference in the relationship between personality traits and changes in depressive symptoms before and after the COVID-19 outbreak: A follow-up study among Chinese adults

OBJECTIVES

Increasing depressive symptoms have become an urgent public health concern worldwide. This study aims to explore the correlation between personality traits and changes in depressive symptoms before and after the COVID-19 outbreak and to examine the gender difference in this association further.

METHODS

Data were obtained from the China Family Panel Studies (CFPS, wave in 2018 and 2020). A total of 16,369 residents aged 18 and above were included in this study. Multinomial logistic regression analysis was used to examine whether personality traits were associated with changes in depressive symptoms. We also analyzed whether there was an interaction effect of gender and personality traits on depressive symptoms.

RESULTS

Conscientiousness, extroversion, and agreeableness are negatively associated with depressive symptoms, while neuroticism and openness are positively related. Gender moderates the relationship between personality traits and depressive symptoms. Compared to men, women have demonstrated a stronger association between neuroticism (OR = 0.79; 95 % CI = 0.66, 0.94), conscientiousness (OR = 1.40; 95 % CI = 1.15, 1.69), and persistent depressive symptoms.

LIMITATIONS

Given its longitudinal study design, it is insufficient to draw a causal inference between personality traits and depressive symptoms.

CONCLUSION

Personality traits and their various dimensions are correlated with changes in depressive symptoms. Persistent depressive symptoms are positively related to neuroticism and negatively associated with conscientiousness. Women demonstrate a stronger association between personality traits and persistent depressive symptoms. Thus, in Chinese adults' mental health intervention and prevention programs, personality and gender-specific strategies should be considered, especially in the context of the COVID-19 pandemic.

The genetic architecture of pain intensity in a sample of 598,339 U.S. veterans

Chronic pain is a common problem, with more than one-fifth of adult Americans reporting pain daily or on most days. It adversely affects quality of life and imposes substantial personal and economic costs. Efforts to treat chronic pain using opioids played a central role in precipitating the opioid crisis. Despite an estimated heritability of 25-50%, the genetic architecture of chronic pain is not well characterized, in part because studies have largely been limited to samples of European ancestry. To help address this knowledge gap, we conducted a cross-ancestry meta-analysis of pain intensity in 598,339 participants in the Million Veteran Program, which identified 125 independent genetic loci, 82 of which are novel. Pain intensity was genetically correlated with other pain phenotypes, level of substance use and substance use disorders, other psychiatric traits, education level, and cognitive traits. Integration of the GWAS findings with functional genomics data shows enrichment for putatively causal genes (n = 142) and proteins (n = 14) expressed in brain tissues, specifically in GABAergic neurons. Drug repurposing analysis identified anticonvulsants, beta-blockers, and calcium-channel blockers, among other drug groups, as having potential analgesic effects. Our results provide insights into key molecular contributors to the experience of pain and highlight attractive drug targets.

Investigating the shared genetic architecture and causal relationship between pain and neuropsychiatric disorders

Pain often occurs in parallel with neuropsychiatric disorders. However, the underlying mechanisms and potential causality have not been well studied. We collected the genome-wide association study (GWAS) summary statistics of 26 common pain and neuropsychiatric disorders with sample size ranging from 17,310 to 482,730 in European population. The genetic correlation between pair of pain and neuropsychiatric disorders, as well as the relevant cell types were investigated by linkage disequilibrium (LD) score regression analyses. Then, transcriptome-wide association study (TWAS) was applied to identify the potential shared genes by integrating the gene expression information and GWAS. In addition, Mendelian randomization (MR) analyses were conducted to infer the potential causality between pain and neuropsychiatric disorders. Among the 169 pairwise pain and neuropsychiatric disorders, 55 pairs showed positive correlations (median r_g = 0.43) and 9 pairs showed negative correlations (median r_g =  -0.31). Using MR analyses, 26 likely causal associations were identified, including that neuroticism and insomnia were risk factors for most of short-term pain, and multisite chronic pain was risk factor for neuroticism, insomnia, major depressive disorder and attention deficit/hyperactivity disorder, and vice versa. The signals of pain and neuropsychiatric disorders tended to be enriched in the functional regions of cell types from central nervous system (CNS). A total of 19 genes shared in at least one pain and neuropsychiatric disorder pair were identified by TWAS, including AMT, NCOA6, and UNC45A, which involved in glycine degradation, insulin secretion, and cell proliferation, respectively. Our findings provided the evidence of shared genetic structure, causality and potential shared pathogenic mechanisms between pain and neuropsychiatric disorders, and enhanced our understanding of the comorbidities of pain and neuropsychiatric disorders.

A Shared Genetic Signature for Common Chronic Pain Conditions and its Impact on Biopsychosocial Traits

The multiple comorbidities & dimensions of chronic pain present a formidable challenge in disentangling its aetiology. Here, we performed genome-wide association studies of 8 chronic pain types using UK Biobank data (N =4,037-79,089 cases; N = 239,125 controls), followed by bivariate linkage disequilibrium-score regression and latent causal variable analyses to determine (respectively) their genetic correlations and genetic causal proportion (GCP) parameters with 1,492 other complex traits. We report evidence of a shared genetic signature across chronic pain types as their genetic correlations and GCP directions were broadly consistent across an array of biopsychosocial traits. Across 5,942 significant genetic correlations, 570 trait pairs could be explained by a causal association (|GCP| >0.6; 5% false discovery rate), including 82 traits affected by pain while 410 contributed to an increased risk of chronic pain (cf. 78 with a decreased risk) such as certain somatic pathologies (eg, musculoskeletal), psychiatric traits (eg, depression), socioeconomic factors (eg, occupation) and medical comorbidities (eg, cardiovascular disease). This data-driven phenome-wide association analysis has demonstrated a novel and efficient strategy for identifying genetically supported risk & protective traits to enhance the design of interventional trials targeting underlying causal factors and accelerate the development of more effective treatments with broader clinical utility. PERSPECTIVE: Through large-scale phenome-wide association analyses of >1,400 biopsychosocial traits, this article provides evidence for a shared genetic signature across 8 common chronic pain types. It lays the foundation for further translational studies focused on identifying causal genetic variants and pathophysiological pathways to develop novel diagnostic & therapeutic technologies and strategies.

A Meta-Analysis of the Genome-Wide Association Studies on Two Genetically Correlated Phenotypes Suggests Four New Risk Loci for Headaches

Headache is one of the commonest complaints that doctors need to address in clinical settings. The genetic mechanisms of different types of headache are not well understood while it has been suggested that self-reported headache and self-reported migraine were genetically correlated. In this study, we performed a meta-analysis of genome-wide association studies (GWAS) on the self-reported headache phenotype from the UK Biobank and the self-reported migraine phenotype from the 23andMe using the Unified Score-based Association Test (metaUSAT) software for genetically correlated phenotypes (N = 397,385). We identified 38 loci for headaches, of which 34 loci have been reported before and four loci were newly suggested. The LDL receptor related protein 1 (LRP1)-Signal Transducer and Activator of Transcription 6 (STAT6)-S hort chain D ehydrogenase/R eductase family 9C member 7 (SDR9C7) region in chromosome 12 was the most significantly associated locus with a leading p value of 1.24 × 10-62 of rs11172113. The One Cut homeobox 2 (ONECUT2) gene locus in chromosome 18 was the strongest signal among the four new loci with a p value of 1.29 × 10-9 of rs673939. Our study demonstrated that the genetically correlated phenotypes of self-reported headache and self-reported migraine can be meta-analysed together in theory and in practice to boost study power to identify more variants for headaches. This study has paved way for a large GWAS meta-analysis involving cohorts of different while genetically correlated headache phenotypes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00078-7.

Chronic pain conditions and risk of suicidal behavior: a 10-year longitudinal co-twin control study

BACKGROUND

Understanding the relationship between chronic pain conditions and suicidal behavior-suicide attempt, other intentional self-harm, and death by suicide-is imperative for suicide prevention efforts. Although chronic pain conditions are associated with suicidal behaviors, these associations might be attributed to unmeasured confounding or mediated via pain comorbidity.

METHODS

We linked a population-based Swedish twin study (N=17,148 twins) with 10 years of longitudinal, nationwide records of suicidal behavior from health and mortality registers through 2016. To investigate whether pain comorbidity versus specific pain conditions were more important for later suicidal behavior, we modeled a general factor of pain and two independent specific pain factors (measuring pain-related somatic symptoms and neck-shoulder pain, respectively) based on 9 self-reported chronic pain conditions. To examine whether the pain-suicidal behavior associations were attributable to familial confounding, we applied a co-twin control model.

RESULTS

Individuals scoring one standard deviation above the mean on the general pain factor had a 51% higher risk of experiencing suicidal behavior (odds ratio (OR), 1.51; 95% confidence interval (CI), 1.34-1.72). The specific factor of somatic pain was also associated with increased risk for suicidal behavior (OR, 1.80; 95% CI, 1.45-2.22]). However, after adjustment for familial confounding, the associations were greatly attenuated and not statistically significant within monozygotic twin pairs (general pain factor OR, 0.89; 95% CI, 0.59-1.33; somatic pain factor OR, 1.02; 95% CI, 0.49-2.11) CONCLUSION: Clinicians might benefit from measuring not only specific types of pain, but also pain comorbidity; however, treating pain might not necessarily reduce future suicidal behavior, as the associations appeared attributable to familial confounding.

Accumulation of health complaints is associated with persistent musculoskeletal pain two years later in adolescents: The Fit Futures study

There is limited knowledge on the association between different health complaints and the development of persistent musculoskeletal pain in adolescents. The aims of this study were to assess whether specific health complaints, and an accumulation of health complaints, in the first year of upper-secondary school, were associated with persistent musculoskeletal pain 2 years later. We used data from a population-based cohort study (the Fit Futures Study in Norway), including 551 adolescents without persistent musculoskeletal pain at baseline. The outcome was persistent musculoskeletal pain (≥3 months) 2 years after inclusion. The following self-reported health complaints were investigated as individual exposures at baseline: asthma, allergic rhinitis, atopic eczema, headache, abdominal pain and psychological distress. We also investigated the association between the accumulated number of self-reported health complaints and persistent musculoskeletal pain 2 years later. Logistic regression analyses estimated adjusted odds ratios (ORs) with 95% confidence intervals (CIs). At the 2-year follow-up, 13.8% (95% CI [11.2-16.9]) reported persistent musculoskeletal pain. Baseline abdominal pain was associated with persistent musculoskeletal pain 2 years later (OR 2.33, 95% CI [1.29-4.19], p = 0.01). Our analyses showed no statistically significant associations between asthma, allergic rhinitis, atopic eczema, headache or psychological distress and persistent musculoskeletal pain at the 2-year follow-up. For the accumulated number of health complaints, a higher odds of persistent musculoskeletal pain at the 2-year follow-up was observed for each additional health complaint at baseline (OR 1.33, 95% CI [1.07-1.66], p = 0.01). Health care providers might need to take preventive actions in adolescents with abdominal pain and in adolescents with an accumulation of health complaints to prevent development of persistent musculoskeletal pain. The potential multimorbidity perspective of adolescent musculoskeletal pain is an important topic for future research to understand the underlying patterns of persistent pain conditions in adolescents.

The genetic structure of pain in depression patients: A genome-wide association study and proteome-wide association study

BACKGROUND

Comparing with the general population, the pain in depression patients has more complex biological mechanism. We aim to explore the etiological mechanism of pain in depression patients from the perspective of genetics.

METHODS

Utilizing the UK Biobank samples with self-reported depression status or PHQ score ≥10, we conducted genome-wide association studies (GWAS) of seven pain traits (N = 1,133-58,349). Additionally, we used FUSION pipeline to perform proteome-wide association study (PWAS) and transcriptome-wide association study (TWAS) by integrating GWAS summary data with two different proteome reference weights (ROS/MAP and Banner) and Rnaseq gene expression reference weights, respectively.

RESULTS

GWAS identified 3 significant genes associated with different pain traits in depression patients, including TRIOBP (P_GWAS = 4.48 × 10^-8) for stomach or abdominal pain, SLC9A9(P_GWAS = 2.77 × 10^-8) for multisite chronic pain (MCP) and ADGRF1 (P_GWAS = 1.51 × 10^-8) for neck or shoulder pain. In addition, PWAS and TWAS analysis also identified multiple candidate genes associated with different pain traits in depression patients, such as TPRG1L (P_PWAS-Banner = 3.38 × 10^-2) and SIRPA (P_PWAS-Banner = 3.65 × 10^-2) for MCP, etc. Notably, when comparing the results of PWAS and TWAS analysis, we found overlapping candidate genes in these pain traits, such as GSTM3 (P_PWAS-_Banner = 3.38 × 10^-2, P_TWAS = 6.92 × 10^-3) in the stomach or abdominal pain phenotype, ATG7 (P_PWAS-_Rosmap = 3.15 × 10^-2, P_TWAS = 2.98 × 10^-2) in the MCP, etc. CONCLUSIONS: We identified multiple novel candidate genes for pain traits in depression patients from different perspectives of genetics, which provided novel clues for understanding the genetic mechanisms underlying the pain in depression patients.

An Italian Twin Study of Non-Cancer Chronic Pain as a Wide Phenotype and Its Intensity

Background and Objectives: Non-cancer chronic pain (CP) results from the interaction between genetic and environmental factors. Twin studies help to estimate genetic and environmental contributions to complex traits such as CP. To date, twin studies on the heritability of pain phenotypes have relied almost exclusively on specific diagnoses, neglecting pain intensity. This study aims to estimate the genetic and environmental contributions to CP occurrence as a wide phenotype and its intensity among a non-clinical population. Materials and Methods: A nationwide online survey was conducted in February 2020 on 6000 adult twins enrolled in the Italian Twin Registry. A five-item questionnaire, designed and validated by our study group, was administered to detect the CP condition along with its intensity, underlying causes or triggers, treatments, and self-perceived efficacy. The twin study design was used to infer the relative weight of genes and environment on CP occurrence and intensity, and biometrical modelling was applied to these phenotypes. Results: A total of 3258 twins, aged ≥18, replied to the online survey (response rate 54%). These included 762 intact pairs (mean age: 39 years; age range: 18–82 years; 34% male; CP prevalence: 24%), of whom 750 pairs were subjected to biometrical modelling after the exclusion of pairs with either unknown zygosity or cancer-associated CP. Broad-sense heritability estimates were driven by non-additive genetic effects and were 0.36 (0.19–0.51) for CP occurrence and 0.31 (0.16–0.44) for CP intensity. No evidence emerged for either sex differences in genetic and environmental variance components or interactions of these components with age. Conclusions: Moderate non-additive genetic components were suggested for non-cancer CP occurrence and its intensity. These results encourage further research on the gene–gene interactions underlying CP liability and associated phenotypes, and also strengthen the need for prevention strategies to avoid CP occurrence or to decrease pain intensity.

Genome-wide association study of pain sensitivity assessed by questionnaire and the cold pressor test

ABSTRACT

We deployed an online pain sensitivity questionnaire (PSQ) and an at-home version of the cold pressor test (CPT) in a large genotyped cohort. We performed genome-wide association studies on the PSQ score (25,321 participants) and CPT duration (6853). We identified one new genome-wide significant locus associated with the PSQ score, which was located in the TSSC1 (also known as EIPR1 ) gene (rs58194899, OR = 0.950 [0.933-0.967], P -value = 1.9 × 10 -8 ). Although high pain sensitivity measured by both PSQ and CPT was associated with individual history of chronic and acute pains, genetic correlation analyses surprisingly suggested an opposite direction: PSQ score was inversely genetically correlated with neck and shoulder pain ( rg = -0.71), rheumatoid arthritis (-0.68), and osteoarthritis (-0.38), and with known risk factors, such as the length of working week (-0.65), smoking (-0.36), or extreme BMI (-0.23). Gene-based analysis followed by pathway analysis showed that genome-wide association studies results were enriched for genes expressed in the brain and involved in neuronal development and glutamatergic synapse signaling pathways. Finally, we confirmed that females with red hair were more sensitive to pain and found that genetic variation in the MC1R gene was associated with an increase in self-perceived pain sensitivity as assessed by the PSQ.

Brain-specific genes contribute to chronic but not to acute back pain

Introduction

Back pain is the leading cause of disability worldwide. Although most back pain cases are acute, 20% of acute pain patients experience chronic back pain symptoms. It is unclear whether acute pain and chronic pain have similar or distinct underlying genetic mechanisms.

Objectives

To characterize the molecular and cellular pathways contributing to acute and chronic pain states.

Methods

Cross-sectional observational genome-wide association study.

Results

A total of 375,158 individuals from the UK Biobank cohort were included in the discovery of genome-wide association study. Of those, 70,633 (19%) and 32,209 (9%) individuals met the definition of chronic and acute back pain, respectively. A total of 355 single nucleotide polymorphism grouped into 13 loci reached the genome-wide significance threshold (5x10^-8) for chronic back pain, but none for acute. Of these, 7 loci were replicated in the Nord-Trøndelag Health Study (HUNT) cohort (19,760 chronic low back pain cases and 28,674 pain-free controls). Single nucleotide polymorphism heritability was 4.6% (P=1.4x10^-78) for chronic back pain and 0.81% (P=1.4x10-8) for acute back pain. Similar differences in heritability estimates between acute and chronic back pain were found in the HUNT cohort: 3.4% (P=0.0011) and 0.6% (P=0.851), respectively. Pathway analyses, tissue-specific heritability enrichment analyses, and epigenetic characterization suggest a substantial genetic contribution to chronic but not acute back pain from the loci predominantly expressed in the central nervous system.

Conclusion

Chronic back pain is substantially more heritable than acute back pain. This heritability is mostly attributed to genes expressed in the brain.

Genetic correlation between female infertility and mental health and lifestyle factors: A linkage disequilibrium score regression study

Background and Aims

Female fertility is a heterogeneous condition of complete psychosocial and physical well-being. Observational studies have revealed that women with infertility have varying degrees of poor mental status and lifestyle choices in varying degrees. However, the genetic contribution to female infertility remains elusive. Our study aimed to explore the genetic correlations between female infertility and mental health and lifestyle factors.

Methods

The genome-wide association study (GWAS) data sets of characteristics related to mental health and lifestyle were obtained from the IEU OpenGWAS database. The GWAS data sets of female infertility were derived from the Finggen database. Linkage disequilibrium score regression was performed to systematically estimate the pairwise genetic correlations between female infertility and a set of mental health- and lifestyle-related traits.

Results

The genetic correlation analysis revealed a moderate and positive genetic correlation between depressive symptoms, major depressive disorder, and female infertility. Similarly, worry and the personality trait of neuroticism displayed a moderate positive genetic correlation with female infertility. Adversely, a negative and moderate genetic correlation was observed between strenuous sports or exercises and female infertility.

Conclusion

The study demonstrated genetic correlations between female infertility and mental health status, including depression, worry, and neuroticism. Additionally, we observed that females with better physical activity may have reduced risks of female infertility. These findings would serve as a fundamental resource for understanding the genetic mechanisms of the effects of mental health and lifestyle factors on female infertility.

A scoping review and comparison of approaches for measuring genetic heterogeneity in psychiatric disorders

An improved understanding of genetic etiological heterogeneity in a psychiatric condition may help us (a) isolate a neurophysiological 'final common pathway' by identifying its upstream genetic origins and (b) facilitate characterization of the condition's phenotypic variation. This review aims to identify existing genetic heterogeneity measurements in the psychiatric literature and provides a conceptual review of their mechanisms, limitations, and assumptions. The Scopus database was searched for studies that quantified genetic heterogeneity or correlation of psychiatric phenotypes with human genetic data. Ninety studies were included. Eighty-seven reports quantified genetic correlation, five applied genomic structural equation modelling, three evaluated departure from the Hardy-Weinberg equilibrium at one or more loci, and two applied a novel approach known as MiXeR. We found no study that rigorously measured genetic etiological heterogeneity across a large number of markers. Developing such approaches may help better characterize the biological diversity of psychopathology.

Reciprocal interaction between depression and pain: results from a comprehensive bidirectional Mendelian randomization study and functional annotation analysis

ABSTRACT

To understand a putative causal link for depression and pain, we retrieved summary statistics from genome-wide association studies conducted for pain at 7 different body sites (N = 151,922-226,683) and major depression disorder (MDD, Ncase/control = 246,363/561,190). We conducted a bidirectional Mendelian randomization analysis using distinct genome-wide association studies-identified single nucleotide polymorphisms for each trait as instrumental variables and performed several sensitivity analyses to verify Mendelian randomization assumptions. We also conducted functional annotation analysis using 396 tissue-specific annotations from the roadmap project. Across 7 different body sites, genetic predisposition to depression was associated with pain at the neck/shoulder (odds ratio [OR] = 1.08 per one log-unit increase in depression risk, 95% confidence interval [CI]: 1.06-1.10), back (OR = 1.05, 95% CI: 1.04-1.07), abdominal/stomach (OR = 1.03, 95% CI: 1.02-1.04), as well as headache (OR = 1.10, 95% CI: 1.07-1.12), but not with pain on the face, hip, and knee. In the reverse direction, genetically instrumented multisite chronic pain (OR = 1.78 per one increment in the number of pain site, 95% CI: 1.51-2.11) and headache (OR = 1.55 per one log-unit increase in headache risk, 95% CI = 1.13-2.10) were associated with MDD. Functional annotation analysis showed differential clustering patterns where depression clustered closely with headache and neck/shoulder pain, exhibiting substantial brain tissue enrichment. Our study indicates that depression is a causal risk factor for headache and pain localized at neck/shoulder, back, and abdominal/stomach, rather than pain at face, hip, and knee, and suggests common neurological pathologies underlying the development of depression, headache, and neck/shoulder pain.

Genetic basis to structural grey matter associations with chronic pain

Structural neuroimaging studies of individuals with chronic pain conditions have often observed decreased regional grey matter at a phenotypic level. However, it is not known if this association can be attributed to genetic factors. Here we employed a novel integrative data-driven and hypothesis-testing approach to determine whether there is a genetic basis to grey matter morphology differences in chronic pain. Using publicly available genome-wide association study summary statistics for regional chronic pain conditions (n = 196 963) and structural neuroimaging measures (n = 19 629-34 000), we applied bivariate linkage disequilibrium-score regression and latent causal variable analyses to determine the genetic correlations (rG) and genetic causal proportion (GCP) between these complex traits, respectively. Five a priori brain regions (i.e. prefrontal cortex, cingulate cortex, insula, thalamus and superior temporal gyrus) were selected based on systematic reviews of grey matter morphology studies in chronic pain. Across this evidence-based selection of five brain regions, 10 significant negative genetic correlations (out of 369) were found (false discovery rate < 5%), suggesting a shared genetic basis to both reduced regional grey matter morphology and the presence of chronic pain. Specifically, negative genetic correlations were observed between reduced insula grey matter morphology and chronic pain in the abdomen (mean insula cortical thickness), hips (left insula volume) and neck/shoulders (left and right insula volume). Similarly, a shared genetic basis was found for reduced posterior cingulate cortex volume in chronic pain of the hip (left and right posterior cingulate), neck/shoulder (left posterior cingulate) and chronic pain at any site (left posterior cingulate); and for reduced pars triangularis volume in chronic neck/shoulder (left pars triangularis) and widespread pain (right pars triangularis). Across these negative genetic correlations, a significant genetic causal proportion was only found between mean insula thickness and chronic abdominal pain [rG (standard error, SE) = -0.25 (0.08), P = 1.06 × 10-3; GCP (SE) = -0.69 (0.20), P = 4.96 × 10-4]. This finding suggests that the genes underlying reduced cortical thickness of the insula causally contribute to an increased risk of chronic abdominal pain. Altogether, these results provide independent corroborating evidence for observational reports of decreased grey matter of particular brain regions in chronic pain. Further, we show for the first time that this association is mediated (in part) by genetic factors. These novel findings warrant further investigation into the neurogenetic pathways that underlie the development and prolongation of chronic pain conditions.

Implications on hypnotherapy: Neuroplasticity, epigenetics and pain

We provide a brief review about the significance of hypnosis with respect to applications and physiological processes in hypnotherapy. Our review concludes that hypnosis is a promising method to manage acute and chronic pain. In addition, we discuss indications pointing toward the view that hypnosis can induce changes in neuroplasticity possibly involving epigenetic mechanisms.

Post-inflammatory Abdominal Pain in Patients with Inflammatory Bowel Disease During Remission: A Comprehensive Review

Patients with inflammatory bowel disease often experience ongoing pain even after achieving mucosal healing (i.e., post-inflammatory pain). Factors related to the brain-gut axis, such as peripheral and central sensitization, altered sympatho-vagal balance, hypothalamic-pituitary-adrenal axis activation, and psychosocial factors, play a significant role in the development of post-inflammatory pain. A comprehensive study investigating the interaction between multiple predisposing factors, including clinical psycho-physiological phenotypes, molecular mechanisms, and multi-omics data, is still needed to fully understand the complex mechanism of post-inflammatory pain. Furthermore, current treatment options are limited and new treatments consistent with the underlying pathophysiology are needed to improve clinical outcomes.

Genome-wide association study identifies RNF123 locus as associated with chronic widespread musculoskeletal pain

BACKGROUND AND OBJECTIVES

Chronic widespread musculoskeletal pain (CWP) is a symptom of fibromyalgia and a complex trait with poorly understood pathogenesis. CWP is heritable (48%-54%), but its genetic architecture is unknown and candidate gene studies have produced inconsistent results. We conducted a genome-wide association study to get insight into the genetic background of CWP.

METHODS

Northern Europeans from UK Biobank comprising 6914 cases reporting pain all over the body lasting >3 months and 242 929 controls were studied. Replication of three independent genome-wide significant single nucleotide polymorphisms was attempted in six independent European cohorts (n=43 080; cases=14 177). Genetic correlations with risk factors, tissue specificity and colocalisation were examined.

RESULTS

Three genome-wide significant loci were identified (rs1491985, rs10490825, rs165599) residing within the genes Ring Finger Protein 123 (RNF123), ATPase secretory pathway Ca2+transporting 1 (ATP2C1) and catechol-O-methyltransferase (COMT). The RNF123 locus was replicated (meta-analysis p=0.0002), the ATP2C1 locus showed suggestive association (p=0.0227) and the COMT locus was not replicated. Partial genetic correlation between CWP and depressive symptoms, body mass index, age of first birth and years of schooling were identified. Tissue specificity and colocalisation analysis highlight the relevance of skeletal muscle in CWP.

CONCLUSIONS

We report a novel association of RNF123 locus and a suggestive association of ATP2C1 locus with CWP. Both loci are consistent with a role of calcium regulation in CWP. The association with COMT, one of the most studied genes in chronic pain field, was not confirmed in the replication analysis.

Genome-wide association study reveals susceptibility loci for self-reported headache in a large community-based Asian population

BACKGROUND

The genetic substrate for headache in the general population has not been identified in Asians. We investigated susceptible genetic variants for self-reported headache in a large community-based Asian population.

METHODS

We conducted a genome-wide association study in participants recruited from a community-based cohort to identify the genetic variants associated with headache in Taiwanese. All participants received a structured questionnaire for self-reported headache. A total of 2084 patients with "self-reported headache" and 11,822 age- and sex-matched controls were enrolled. Gene enrichment analysis using the Genotype-Tissue Expression version 6 database was performed to explore the potential function of the identified variants.

RESULTS

We identified two novel loci, rs10493859 in TGFBR3 and rs13312779 in FGF23, that are functionally relevant to vascular function and migraine to be significantly associated with self-reported headache after adjusting age, sex and top 10 principal components (p = 8.53 × 10^-11 and p = 1.07 × 10^-8, respectively). Gene enrichment analysis for genes with GWAS suggestive significance (p < 10^-6) demonstrated that the expression of these genes was significantly enriched in the artery (p = 8.18 × 10^-4) and adipose tissue (p = 8.95 × 10^-4).

CONCLUSION

Our results suggest that vascular dysfunction might play important roles in the pathogenesis of self-reported headache in Asian populations.

A genome-wide association study finds genetic variants associated with neck or shoulder pain in UK Biobank

Background

Common types of musculoskeletal conditions include pain in the neck and shoulder areas. This study seeks to identify the genetic variants associated with neck or shoulder pain based on a genome-wide association approach using 203 309 subjects from the UK Biobank cohort and look for replication evidence from the Generation Scotland: Scottish Family Health Study (GS:SFHS) and TwinsUK.

Methods

A genome-wide association study was performed adjusting for age, sex, BMI and nine population principal components. Significant and independent genetic variants were then sent to GS:SFHS and TwinsUK for replication.

Results

We identified three genetic loci that were associated with neck or shoulder pain in the UK Biobank samples. The most significant locus was in an intergenic region in chromosome 17, rs12453010, having P = 1.66 × 10⁻¹¹. The second most significant locus was located in the FOXP2 gene in chromosome 7 with P = 2.38 × 10⁻¹⁰ for rs34291892. The third locus was located in the LINC01572 gene in chromosome 16 with P = 4.50 × 10⁻⁸ for rs62053992. In the replication stage, among four significant and independent genetic variants, rs2049604 in the FOXP2 gene and rs62053992 in the LINC01572 gene were weakly replicated in GS:SFHS (P = 0.0240 and P = 0.0202, respectively).

Conclusions

We have identified three loci associated with neck or shoulder pain in the UK Biobank cohort, two of which were weakly supported in a replication cohort. Further evidence is needed to confirm their roles in neck or shoulder pain.

Polygenic risk scoring to assess genetic overlap and protective factors influencing posttraumatic stress, depression, and chronic pain after motor vehicle collision trauma

Posttraumatic stress (PTS), depressive symptoms (DS), and musculoskeletal pain (MSP) are common sequelae of trauma exposure. Although these adverse posttraumatic neuropsychiatric sequelae (APNS) are often studied separately, clinical comorbidity is high. In a cohort of European American motor vehicle collision (MVC) trauma survivors (n = 781), substantial PTS (≥33, IES-R), DS (≥26, CES-D), and MSP (≥4, 0-10 NRS) were identified via a 6-month survey. Genetic risk was estimated using polygenic risk scores (PRSs) calculated from the largest available GWAS datasets of PTSD, MDD, and back pain. We then assessed comorbidity and genetic risk influence for developing chronic PTS, DS, and MSP after MVC. Secondary analyses explored whether common social determinants of health ameliorate genetic vulnerability. We found that 6 months after MVC, nearly half 357/781 (46%) of the participants had substantial PTS, DS, and/or MSP, and overlap was common (PTS + MSP (23%), DS + MSP (18%), PTS + DS (12%)). Genetic risk predicted post-MVC outcomes. PTSD-PRSs predicted PTS and DS (R² = 2.21% and 2.77%, p_adj < 0.01), MDD-PRSs predicted DS and MSP (R² = 1.89%, p_adj < 0.01) and 0.79%, p_adj < 0.05), and back pain-PRS predicted MSP (R² = 1.49%, p_adj < 0.01). Individuals in the highest quintile of PTSD-PRSs had 2.8 and 3.5 times the odds of developing PTS and DS vs. the lowest quintile (95% CI = 1.39-5.75 and 1.58-7.76). Among these high-risk individuals, those living in non-disadvantaged neighborhoods and with college education had 47% (p = 0.048) and 52% (p = 0.04) less risk of developing PTS, and those with high social support had 60% (p = 0.008) less risk of developing DS. Overall, genetic factors influence the risk of APNS after MVC, genetic risk of distinct APNS are overlapping, and specific social determinants greatly augment genetic risk of APNS development after MVC.

Breathlessness across generations: results from the RHINESSA generation study

Background

Breathlessness is a major cause of suffering and disability globally. The symptom relates to multiple factors including asthma and lung function, which are influenced by hereditary factors. No study has evaluated potential inheritance of breathlessness itself across generations.

Methods

We analysed the association between breathlessness in parents and their offspring in the Respiratory Health in Northern Europe, Spain and Australia generation study. Data on parents and offspring aged ≥18 years across 10 study centres in seven countries included demographics, self-reported breathlessness, asthma, depression, smoking, physical activity level, measured Body Mass Index and spirometry. Data were analysed using multivariable logistic regression accounting for clustering within centres and between siblings.

Results

A total of 1720 parents (mean age at assessment 36 years, 55% mothers) and 2476 offspring (mean 30 years, 55% daughters) were included. Breathlessness was reported by 809 (32.7%) parents and 363 (14.7%) offspring. Factors independently associated with breathlessness in parents and offspring included obesity, current smoking, asthma, depression, lower lung function and female sex. After adjusting for potential confounders, parents with breathlessness were more likely to have offspring with breathlessness, adjusted OR 1.8 (95% CI 1.1 to 2.9). The association was not modified by sex of the parent or offspring.

Conclusion

Parents with breathlessness were more likely to have children who developed breathlessness, after adjusting for asthma, lung function, obesity, smoking, depression and female sex in both generations. The hereditary components of breathlessness need to be further explored.

Effects of intrathecal and intracerebroventricular microinjection of kaempferol on pain: possible mechanisms of action

Background and purpose:

Kaempferol (KM), a flavonoid, has an anti-inflammatory and anticancer effect and prevents many metabolic diseases. Nonetheless, very few studies have been done on the antinociceptive effects of KM. This research aimed at assessing the involvement of opioids, gamma-aminobutyric acid (GABA) receptors, and inflammatory mediators in the antinociceptive effects of KM in male Wistar rats.

Experimental approach:

The intracerebroventricular and/or intrathecal administration of the compounds was done for examining their central impacts on the thermal and chemical pain by the tail-flick and formalin paw tests. For assessing the role of opioid and GABA receptors in the possible antinociceptive effects of KM, several antagonists were used. Also, a rotarod test was carried out for assessing motor performance.

Findings/Results:

The intracerebroventricular and/or intrathecal microinjections of KM (40 μg/rat) had partially antinociceptive effects in the tail-flick test in rats (P < 0.05). In the formalin paw model, the intrathecal microinjection of KM had antinociceptive effects in phase 1 (20 and 40 μg/rat; P < 0.05 and P < 0.01, respectively) and phase 2 (20 and 40 μg/rat; P < 0.01 and P < 0.001, respectively). Using naloxonazine and/or bicuculline approved the involvement of opioid and GABA receptors in the central antinociceptive effects of KM, respectively. Moreover, KM reduced the expression levels of caspase 6, interleukin-1β, tumor necrosis factor-α, and interleukin-6. The antinociceptive effects of KM were not linked to variations in the locomotor activity.

Conclusion and implications:

It can be concluded that KM has remarkable antinociceptive effects at a spinal level, which is associated with the presence of the inflammatory state. These impacts were undetectable following injections in the lateral ventricle. The possible mechanisms of KM antinociception are possibly linked to various modulatory pathways, including opioid and GABA receptors.

Analgesic and Antidepressant Effects of the Clinical Glutamate Modulators Acetyl-L-Carnitine and Ketamine

Pain and depression are leading causes of disability and of profound social and economic burden. Their impact is aggravated by their chronicity and comorbidity and the insufficient efficacy of current treatments. Morphological and functional metabolism studies link chronic pain and depressive disorders to dysfunctional neuroplastic changes in fronto-limbic brain regions that control emotional responses to painful injuries and stressful events. Glutamate modulators are emerging new therapies targeting dysfunctional brain areas implicated in the generation and maintenance of chronic pain and depression. Here, we report the effects of two clinically approved glutamate modulators: acetyl-L-carnitine (ALCAR) and S, R(±)ketamine (KET). ALCAR is a natural neurotrophic compound currently marketed for the treatment of neuropathies. KET is the prototypical non-competitive antagonist at N-methyl-D-aspartate glutamate receptors and a clinically approved anesthetic. Although they differ in pharmacological profiles, ALCAR and KET both modulate aminergic and glutamatergic neurotransmissions and pain and mood. We assessed in rats the effects of ALCAR and KET on cerebral metabolic rates for glucose (rCMRglc) and assessed clinically the effects of ALCAR in chronic pain and of KET in post-operative pain. ALCAR and KET increased rCMRglc at similar degrees in prefrontal, somatosensory, and cingulate cortices, and KET increased rCMRglc at a different, much larger, degree in limbic and dopaminergic areas. While rCMRglc increases in prefrontal cortical areas have been associated with analgesic and antidepressant effects of ALCAR and KET, the marked metabolic increases KET induces in limbic and dopaminergic areas have been related to its psychotomimetic and abuse properties. In patients with chronic neuropathic pain, ALCAR (1,000 mg/day) yielded to a fast (2 weeks) improvement of mood and then of pain and quality of life. In day-surgery patients, KET improved dischargeability and satisfaction. In obese patients undergoing bariatric surgery, a single, low dose of KET (0.5 mg/kg) at induction of anesthesia determined a very fast (hours) amelioration of post-operative depression and pain and an opioid-sparing effect. These findings indicate that ALCAR and KET, two non-selective glutamate modulators, still offer viable therapeutic options in comorbid pain and depression.

Comorbid Chronic Pain and Depression: Shared Risk Factors and Differential Antidepressant Effectiveness

The bidirectional relationship between depression and chronic pain is well-recognized, but their clinical management remains challenging. Here we characterize the shared risk factors and outcomes for their comorbidity in the Australian Genetics of Depression cohort study (N = 13,839). Participants completed online questionnaires about chronic pain, psychiatric symptoms, comorbidities, treatment response and general health. Logistic regression models were used to examine the relationship between chronic pain and clinical and demographic factors. Cumulative linked logistic regressions assessed the effect of chronic pain on treatment response for 10 different antidepressants. Chronic pain was associated with an increased risk of depression (OR = 1.86 [1.37-2.54]), recent suicide attempt (OR = 1.88 [1.14-3.09]), higher use of tobacco (OR = 1.05 [1.02-1.09]) and misuse of painkillers (e.g., opioids; OR = 1.31 [1.06-1.62]). Participants with comorbid chronic pain and depression reported fewer functional benefits from antidepressant use and lower benefits from sertraline (OR = 0.75 [0.68-0.83]), escitalopram (OR = 0.75 [0.67-0.85]) and venlafaxine (OR = 0.78 [0.68-0.88]) when compared to participants without chronic pain. Furthermore, participants taking sertraline (OR = 0.45 [0.30-0.67]), escitalopram (OR = 0.45 [0.27-0.74]) and citalopram (OR = 0.32 [0.15-0.67]) specifically for chronic pain (among other indications) reported lower benefits compared to other participants taking these same medications but not for chronic pain. These findings reveal novel insights into the complex relationship between chronic pain and depression. Treatment response analyses indicate differential effectiveness between particular antidepressants and poorer functional outcomes for these comorbid conditions. Further examination is warranted in targeted interventional clinical trials, which also include neuroimaging genetics and pharmacogenomics protocols. This work will advance the delineation of disease risk indicators and novel aetiological pathways for therapeutic intervention in comorbid pain and depression as well as other psychiatric comorbidities.

Clustering of Social and Physical Pain Variables and Their Association With Mortality in Two Population-Based Cohorts

OBJECTIVE

Social pain and physical pain are related bidirectionally, but how these variables cluster in the population is unknown.

METHODS

This study included 2833 women from the Study of Women's Health Across the Nation (SWAN), a community-based cohort of middle-aged women, and 3972 women from the Pathways Study, a population-based cohort of women diagnosed with American Joint Committee on Cancer stages I-IV breast cancer diagnosed between 2005 and 2013. Women provided data on measures related to social pain (social network size, social support, loneliness, social well-being) and physical pain (sensitivity to pain, bodily pain) at study baseline. Analyzing each cohort separately, we used latent class analysis to evaluate social-physical pain clusters, logistic regression to evaluate predictors of categorization into clusters, and Cox proportional hazards models to evaluate associations of clusters with all-cause mortality. We also performed a meta-analysis to combine cohort mortality associations.

RESULTS

Each cluster analysis produced a "low social-physical pain" cluster (SWAN, 48.6%; Pathways, 35.2%) characterized by low social and pain symptoms, a "high social-physical pain" cluster (SWAN, 17.9%; Pathways, 17.9%) characterized by high symptoms, and a "low social/high physical pain" cluster of women with high pain and compromised social functioning but otherwise low social symptoms (SWAN, 33.5%; Pathways, 46.9%). In meta-analysis, categorization into the high social-physical pain cluster was associated with elevated mortality (adjusted hazard ratio = 1.34, 95% confidence interval = 1.05-1.71, Q statistic = 0.782), compared with those in the low social-physical pain cluster.

CONCLUSIONS

In two cohorts of women, latent class analysis produced similar sets of social-physical pain clusters, with the same proportion having both high social and pain symptoms; women in this cluster had elevated mortality.

Preclinical Considerations about Affective Disorders and Pain: A Broadly Intertwined, yet Often Under-Explored, Relationship Having Major Clinical Implications

Background: Pain, a distinctive undesirable experience, encompasses several different and fluctuating presentations across varying mood disorders. Therefore, the present narrative review aimed to shed further light on the matter, accounting for both experimental animal models and clinical observations about major depressive disorder (MDD) pathology. Method: Major databases were inquired from inception until April 2016 for records about MDD and pain. Results: Pain and MDD are tightly associated with each other in a bi-directional fashion. Several cross-sectional and retrospective studies indicated a high presence of pain in the context of mood disorders, including MDD (up to 65%), but also increased prevalence rates in the case of mood disorders documented among people with a primary diagnosis of either psychological or somatic pain (prevalence rates exceeding 45%). The clinical implications of these observations suggest the need to account for mood and pain manifestations as a whole rather than distinct entities in order to deliver more effective interventions. Limitations: Narrative review, lack of systematic control groups (e.g., people with the primary diagnosis at review, but not the associated comorbidity as a study) to allow reliable comparisons. Prevalence rates and clinical features associated with pain varied across different studies as corresponding operational definitions did. Conclusions: Pain may have a detrimental effect on the course of mood disorders-the opposite holds. Promoting a timely recognition and management of such an often neglected comorbidity would therefore represent a primary goal toward the delivery of effective, multi-disciplinary care.