Traumatic Life Experience and Pain Sensitization: Meta-analysis of Laboratory Findings

Impact of adverse childhood experiences on sensory thresholds in adults living with multimorbidity and chronic pain (the ACE-MAP study): protocol for an observational feasibility study

INTRODUCTION

Exposure to adverse childhood experiences (ACEs) is associated with a range of poor long-term health outcomes, including multimorbidity and chronic pain. Epidemiological evidence underpins much of this relationship; however, psychophysical testing methods, such as quantitative sensory testing (QST), may provide valuable insights into potential mechanisms. Previous studies have shown inconsistent links between ACEs and QST, but the QST profiles of people with multimorbidity have not been reported. We hypothesise that exposure to ACEs is associated with lowered QST thresholds (ie, experience of pain with milder stimuli) and that this association is stronger in adults with multimorbidity and/or chronic pain. The ACE-MAP study is a cross-sectional feasibility study with the primary aim of assessing the feasibility and acceptability of the proposed study procedures. The secondary aim is to generate preliminary data to understand the impact of ACEs on QST thresholds.

METHODS AND ANALYSIS

We plan to recruit 40 participants, with 10 in each of the following groups: (1) chronic pain with multimorbidity; (2) chronic pain without multimorbidity; (3) multimorbidity without chronic pain; and (4) controls. Participants will complete a series of questionnaires (including on ACEs, chronic pain and long-term conditions) and will then take part in QST assessments. The primary study outcomes will include measures of feasibility and acceptability of the proposed study design. The secondary study outcomes will include exploratory analysis on the relationship between ACEs and QST thresholds.

ETHICS AND DISSEMINATION

The study was approved by the Scotland B Research Ethics Committee (reference: 24/SS/0031). Results from the study will be presented at scientific conferences, published in a peer-reviewed journal and shared with patients and members of the public through other media streams.

TRIAL REGISTRATION NUMBER

ISRCTN10049430.

The effect of eye movement desensitization and reprocessing on fibromyalgia: A multiple-baseline experimental case study across ten participants

Fibromyalgia (FM) is a chronic pain disorder characterized by widespread musculoskeletal pain, fatigue, and stiffness in muscles and joints. Traumatic life experiences and post-traumatic stress symptoms play a role in its development and persistence. Although previous research suggests that pain and FM symptoms decrease after eye movement desensitization and reprocessing (EMDR) therapy, its effectiveness has not been investigated in a controlled manner. The present study investigated the effectiveness of a six-session, 90-minute EMDR therapy using a multiple baseline single-case experimental design (SCED) across ten adult females with FM. The SCED involved a baseline, intervention, one- and three-month follow-up phase. The primary outcome was pain. Secondary outcomes included post-traumatic stress symptoms, other FM symptoms (fatigue, stiffness in muscles and joints), and the impact of FM on daily activities and sleep. Data were statistically analyzed by primarily testing means across phases on an individual and group level. Post-traumatic stress symptoms improved significantly in seven participants. Pain severity decreased significantly in six participants, with three of them maintaining significant improvement three months later. One participant showed clinically relevant change one month later. Furthermore, improvements were observed in secondary outcome measures. The findings support the efficacy of EMDR in reducing FM symptoms.

The relationship between traumatic exposure and pain perception in children: the moderating role of posttraumatic symptoms

ABSTRACT

Adverse childhood experiences (ACEs) affect approximately half of all children worldwide. These experiences have been linked to increased pain sensitivity in adulthood and a higher likelihood of developing severe chronic pain. However, most studies have assessed the effects of ACEs retrospectively, long after they occurred, leaving room for other factors to influence the observed outcomes. We investigated, for the first time, the association between ACEs and concurrent pain perception among young children who live in a conflict zone and are consistently exposed to potentially traumatic experiences. Participants were 60 elementary school children (ages 8-11 years) living in conflict regions (n = 39) or nonconflict regions (n = 21). Posttraumatic stress symptom (PTSS) severity, traumatic exposure, pressure pain threshold (PPT), and mechanical detection threshold (MDT) were measured. Trauma-exposed children had significantly lower PPT than did controls, but MDT was similar across groups. Pressure pain threshold correlated positively with proximity to the conflict zone and inversely with traumatic exposure magnitude and PTSS severity. In addition, PTSSs moderated the relationship between repeated traumatic exposure and PPT. Children with higher PTSS severity displayed pain hypersensitivity regardless of their traumatic exposure level, whereas in children with lower PTSS severity, greater traumatic exposure correlated with pain hypersensitivity. The results suggest that ACEs among children lead to concurrent pain hypersensitivity and distress and may put them at elevated risk of chronic pain early in life. In addition, our findings emphasize the need for identifying children with various PTSS levels to provide tailored interventions and mitigate the long-term negative effects of ACEs.

Veterans with chronic pain: Examining gender differences in pain type, overlap, and the impact of post-traumatic stress disorder

BACKGROUND

Women are more likely to experience multiple overlapping pain conditions (MOPCs) relative to men. Post-traumatic stress disorder can negatively impact the severity and trajectory of chronic pain and its treatment. Specific associations between gender, post-traumatic stress disorder (PTSD), and MOPCs require further examination.

METHODS

A cohort of all Veterans in 2021 who met criteria for one or more of 12 chronic pain types was created using national Veterans Health Administration administrative data. MOPCs were defined as the number of pain types for which each patient met criteria. Multivariable logistic regression models estimated gender differences in frequency for each of the 12 pain subtypes, after controlling for demographics and comorbidities. Negative binomial regression was used to estimate gender differences in the count of MOPCs and to explore moderation effects between gender and PTSD.

RESULTS

The cohort included 1,936,859 Veterans with chronic pain in 2021, which included 12.5% women. Among those with chronic pain, women Veterans had higher rates of MOPCs (mean = 2.3) relative to men (mean = 1.9): aIRR = 1.31, 95% CI: 1.30-1.32. PTSD also served as an independent risk factor for MOPCs in adjusted analysis (aIRR = 1.23, 95% CI: 1.23-1.24). The interaction term between gender and PTSD was not significant (p = 0.87). Independent of PTSD, depressive disorders also served as a strong risk factor for MOPCs (aIRR = 1.37, 95% CI: 1.36-1.37).

CONCLUSIONS

Individuals with MOPCs and PTSD may have complex treatment needs. They may benefit from highly coordinated trauma-sensitive care and integrated interventions that simultaneously address pain and PTSD.

SIGNIFICANCE

Women were significantly more likely than men to experience MOPCs. PTSD was also significantly, independently, associated with MOPCs. Patients, particularly women, may benefit from tailored interventions that address both trauma and MOPCs.

rs12411980 single-nucleotide polymorphism related to PRTFDC1 expression is significantly associated with phantom tooth pain

Phantom tooth pain (PTP) is one type of non-odontogenic neuropathic toothache, which rarely occurs after appropriate pulpectomy or tooth extraction. The cause of PTP is unknown. We investigated pain-related genetic factors that are associated with PTP. Four pain-associated genes, including G protein-coupled receptor 158 (GPR158) and phosphoribosyl transferase domain containing 1 (PRTFDC1), are adjacent to each other on the human genome. Some of these four genes or their genomic region may be related to PTP. We statistically analyzed associations between single-nucleotide polymorphisms (SNPs) in the genomic region and PTP in patients with PTP (PTP group), other orofacial pain (OFP group), and healthy control subjects. We then performed a database search of expression quantitative trait loci (eQTLs). For the seven SNPs that were significantly associated with PTP even after Bonferroni correction, we focused on the rs12411980 tag SNP (p = 9.42 × 10-4). Statistical analyses of the PTP group and healthy subject groups (group labels: NOC and TD) revealed that the rate of the GG genotype of the rs12411980 SNP was significantly higher in the PTP group than in the healthy subject groups (PTP group vs. NOC group: p = 2.92 × 10-4, PTP group vs. TD group: p = 5.46 × 10-4; percentage of GG: 30% in PTP group, 12% in NOC group, 11% in TD group). These results suggest that the GG genotype of the rs12411980 SNP is more susceptible to PTP. The rs2765697 SNP that is in strong linkage disequilibrium with the rs12411980 SNP is an eQTL that is associated with higher PRTFDC1 expression in the minor allele homozygotes in the healthy subject groups of the rs2765697 SNP. Thus, PRTFDC1 expression similarly increases in the minor allele homozygotes (GG genotype) in the healthy subject groups of the rs12411980 SNP, which would lead to greater susceptibility to PTP.