OBJECTIVES:We developed a web application (PACT app) based on Acceptance and Commitment Therapy to support mental health for people with Parkinson's. Here, we assess the app's acceptability and the feasibility of conducting a randomised controlled trial to evaluate its effectiveness. METHOD:This was a two-armed parallel group design with 2:1 allocation to the PACT app or waiting-list control and a single, post-intervention follow-up. Feasibility outcomes included recruitment and retention rate, intervention engagement and satisfaction. Secondary outcomes included measures of anxiety, depression, quality of life, and cost-effectiveness. Treatment effects for secondary outcomes were estimated using linear regression, following the intention-to-treat principle. RESULTS:Fifty-seven people with Parkinson's were randomised to 4 weeks of PACT app (n = 38) or waiting-list control (n = 19). Recruitment, retention rate, intervention use, and acceptability met our progression criteria. Intervention effects were in the expected direction for all outcomes and largest for measures of depression (Hedges g = -0.96; 95% CI = -1.47 to -0.46) and committed action (Hedges g = 0.87; 95% CI = 0.38 to 1.35). CONCLUSION:Progression criteria were met, and PACT was acceptable to people with Parkinson's. It has potential efficacy and cost-effectiveness. A future larger trial to fully evaluate efficacy is needed.Trial registration: ISRCTN65177345 (01/09/2023).

Fibromyalgia is a type of generalized chronic pain condition that causes physical tenderness, fatigue, sleep disturbance, cognitive impairment, and comorbid psychiatric symptoms. Medication and psychotherapy can offer some relief. Acceptance and Commitment Therapy (ACT) is a current treatment approach that focuses on fostering acceptance of symptoms and engagement in meaningful, value-driven activities. However, no systematic attempts at investigating unwanted events and deterioration have been made in relation to ACT for fibromyalgia. This brief report presents findings on the occurrence of characteristics of such incidents in a groupbased ACT-treatment at a specialized pain clinic. Among the 94 patients included, deterioration rates were generally low across most outcome measures. Unwanted events were monitored using the 32-item Negative Effects Questionnaire, a self-report measure covering symptoms, treatment quality, dependency, stigma, hopelessness, and failure. A total of 37.6 % reported having experienced unwanted events during the treatment period, and 43.2 % at post-treatment. Among the most frequently occurring unwanted events reported at posttreatment were "Unpleasant memories resurfaced" (12.7 %), "I experienced more unpleasant feelings" (9.9 %), and "I feel like I am under more stress" (8.3 %). However, unwanted events reported during treatment were not related to treatment outcome. The results point to the importance of monitoring unwanted events during treatment, although these experiences may not interfere with benefits participants obtain, and, presumably, may be part of the theorized change process. Further research is warranted to understand how unwanted events and deterioration might affect adherence and dropout.

Stigma is common in people with chronic pain. At present, however, the measurement of stigma in Spanish-speaking individuals remains a challenge due to a lack of validated measures in Spanish. The present study examines the psychometric properties of the Spanish version of the Stigma Scale for Chronic Illnesses 8-item version (SSCI-8) in people with chronic pain, focusing on dimensionality, factorial invariance, reliability (internal consistency and test-retest), and construct validity. Adults with chronic pain in Spain were recruited from patient associations and social networks to complete an online survey. The final sample comprised 530 individuals aged 18-70, predominantly women (> 90%). Half of the sample completed the SSCI-8 on a second occasion four weeks later. Data analyses supported a one-factor model with correlated errors as the most optimal solution for the SSCI-8 (CFI =.988; TLI =.983; WRMR =.938; RMSEA =.093; 95% CI [.076,.110]) and factorial invariance across different subgroups. SSCI-8 scores showed a normal distribution, good internal consistency, and adequate stability over time. Significant positive correlations were found, as expected, between stigma and depression, anxiety, pain intensity, pain interference, disability, and injustice experiences. Likewise, significant negative correlations were observed with psychological flexibility. The SSCI-8 accounted for incremental variance beyond injustice experiences in predicting the clinical outcomes. The Spanish version of the SSCI-8 appears psychometrically sound as a measure of stigma for use in people with chronic pain. PERSPECTIVE: The full invariance evidence across gender and pain type reported means that total score differences are due to real differences in perceived stigma, rather than observed differences in interpretations of item contents between men and women in pain or with different types of pain.

BackgroundRecent research shows that chronic pain affects 27% of the adult population. For many, pain significantly impairs quality of life and everyday functioning. Behavioral interventions have shown utility, but access remains limited. Digital health solutions can increase reach, but there is a need for user-friendly, feasible, and evidence-based digital interventions. ObjectiveThis study aimed to clarify how a digital behavioral intervention for people with chronic pain can be developed through a user-centered approach to address the needs and preferences of the target population. MethodsThis study used a multimethod approach involving end users, namely, patients with chronic pain and therapists, to develop prototypes for a digital behavioral intervention across 3 phases. In the preparation phase (phase 0), fictional patient personas (n=3) were created to represent the diversity of the target population while emphasizing transdiagnostic features across people with chronic pain. In the design phase (phase 1), qualitative data from focus groups with patients (n=5; aged 37-51 years; 4/5, 80% women; 2/5, 40% diagnosed with Ehlers-Danlos syndrome; 3/5, 60% either undiagnosed or uncertain about their diagnosis) and therapists (n=12 licensed psychologists; aged 29-64 years; 9/12, 75% women) were collected to explore end-user preferences for the intervention design and content. In the testing phase (phase 2), the initial full prototype of the digital intervention was piloted with patients (n=11; aged 36-58 years; 9/11, 82% women; with diverse diagnoses, including migraine, arthritis, fibromyalgia, complex regional pain syndrome, hypermobile Ehlers-Danlos syndrome, herniated disc, chronic fatigue syndrome, and 1/11, 9% cases of undiagnosed pain) and therapists (n=3 licensed psychologists; aged 36-58 y; 3/3, 100% women). The Consolidated Framework for Implementation Research was used to structure analyses of end-user feedback. ResultsOn the basis of end-user input, a 6-week digital behavioral intervention for chronic pain was created. Focus groups highlighted the importance of accessibility and adaptability of the digital intervention, emphasizing the need for tailored content, flexibility (eg, contact with the therapist via asynchronous messaging, telephone, or video calls), and user-friendly design (eg, easy navigation between modules, short microsessions, and visualizations). Average weekly ratings (scale from 1=not at all to 7=very much) by patients during pilot-testing indicated that the intervention was helpful (mean range 4.27-5.45, SD range 1.20-2.20), enjoyable (mean range 3.81-4.81, SD range 1.12-2.08), and understandable (mean range 4.45-6, SD range 1.30-1.86), suggesting initial acceptability and usability of the intervention. ConclusionsThe results illustrated the utility of the patient personas when preparing, of the focus groups when designing, and of the end-user feedback when testing this new digital intervention for people with chronic pain. The findings indicated that the intervention is promising while also providing relevant end-user suggestions (eg, video content, text-to-speech function, and add-on modules) to guide further improvements.

OBJECTIVE:This study investigated whether psychological flexibility, the key construct in the Acceptance and Commitment Therapy (ACT) model of psychological and behavioural change, significantly predicts wellbeing and functioning in people living with and beyond cancer. DESIGN:This was an online, prospective, longitudinal, correlational study with two time points that were approximately three months apart. METHODS:All participants were required to be at least 18 years of age, be in cancer remission and resident in the United Kingdom. Recruitment for Time-point 1 (n = 331) took place from May to July 2023 and Time-point 2 (n = 266; 80% retention rate) took place between Sept and Nov 2023 using Prolific (an online recruitment platform). The mean age was 51.65 (SD = 13.99). The mean length of remission in months was 89.45 (SD = 80.59) and mean years since diagnosis was 8.91 (SD = 6.99). Data were analysed cross-sectionally and longitudinally. Covariates adjusted for included age, years since diagnosis, time in remission, ethnicity, cancer type and cancer stage. RESULTS:Cross-sectional hierarchical regression analyses showed Time-point 1 psychological flexibility significantly (at p < .001) predicted anxiety, depression, stress, fatigue interference, fear of cancer recurrence, quality of life and pain interference. Psychological flexibility at Time-point 1 significantly predicted all psychosocial variables at Time-point 2, while adjusting for confounding variables. CONCLUSIONS:The findings show that psychological flexibility predicts key psychosocial outcomes relevant for people in remission from cancer. This study provides evidence for the relevance of psychological processes targeted in ACT-based interventions in the context of people living with and beyond cancer.

Pain catastrophizing is understood as a negative cognitive and emotional response to pain. Researchers, clinicians, advocates, and patients have reported stigmatizing effects of the term on patients when used clinically and in the media. This report describes the results of an international, observational, cross-sectional study investigation of clinician and researcher (professionals) perspectives on the term pain catastrophizing and whether new terminology is needed or desired. Open-ended electronic surveys were distributed to researchers and clinicians by collaborators, stakeholders, and through social media. Professionals reported on their familiarity with the term, its meaning and impacts, and their use of the term with patients. 1,397 surveys from professionals in 46 countries (48.5% from the U.S.) were received. The sample was almost two-thirds female (61.3%), with a mean age of 56.67 (SD=4.04) years, and comprised of 78.6% clinicians (63.6%, pain specialists; n=698) and 20.3% researchers. The majority were familiar with the term (82.2%; n=1148). Among the 1,098 clinicians, 33.6% had used the term in communication with patients. A content analysis of professionals’ responses to open-ended questions is presented. Coded responses were synthesized into five content categories or themes: (1) pain catastrophizing is an exaggerated response to pain; (2) pain catastrophizing is an unhelpful response to pain; (3) the term pain catastrophizing is stigmatizing; (4) the term pain catastrophizing is clinically useful; (5) patients’ perception of the term varies. Results highlight the continual controversy surrounding the term pain catastrophizing and the need for additional research and education to incorporate patient-centered approaches into clinical and public communications.Perspective:We present a content analysis of international clinician and researcher perspectives on the term pain catastrophizing. This investigation provides the largest depiction to date of the controversy surrounding pain catastrophizing and may guide future efforts to decrease stigma in patients with chronic pain and improve patient-clinician communication.

The Pain Vigilance and Awareness Questionnaire (PVAQ) is widely used to assess attention to pain, but no validated Polish version has been previously available. This study aimed to translate the PVAQ into Polish and evaluate its psychometric properties. Two studies were conducted: Study 1 included 418 chronic pain patients recruited online who completed the scale alongside measures of depression, anxiety, pain catastrophizing, pain anxiety, pain intensity, functional limitations, and psychological flexibility. A follow-up was completed by 79% after 30 days. Study 2 involved 148 hospital-recruited chronic pain patients who completed the adapted scale and measures of pain intensity and functional limitations. None of the previously proposed models describing the factor structure of the PVAQ scale adequately fit the data. However, factor analyses indicated that a 12-item version with two correlated factors–Passive Awareness and Active Vigilance–provided acceptable model fit. The Polish PVAQ showed good internal consistency, moderate test–retest reliability, and expected correlations with related constructs. Interestingly, Passive Awareness (but not Active Vigilance) was positively associated with components of psychological flexibility. The Polish 12-item PVAQ is reliable and valid instrument for assessing pain-related attention in chronic pain samples, aiding healthcare professionals in identifying highly vigilant individuals to tailor interventions accordingly.

Fear and avoidance remain important concepts for understanding chronic pain. The objective of our research was to develop and evaluate a Polish version of a measure to assess these concepts: the 20-item Pain Anxiety Symptoms Scale (PASS-20). The goal also included establishing a cutoff score to differentiate between individuals with a high level of pain-related disability and those with lower levels. The scale underwent back-translation into Polish, and two studies were conducted among individuals reporting chronic pain: in a large online sample (N = 418; 60% women, 40% men; age: 19-86, M = 49), and in a hospital-recruited sample (N = 148; 77% women, 22% men; age: 18-85; M = 57). We assessed validity, internal consistency, and test-retest reliability. Confirmatory factor analyses supported both a model with four correlated factors-cognitive anxiety, physiological responses, avoidance, and fearful thinking-and a hierarchical model with four lower order factors and a higher order factor representing general pain anxiety. There was no evidence of ceiling or floor effects. Cronbach's αs exceeded .82 and .76 for the online and hospital-recruited samples, respectively, indicating robust internal consistency. The translated PASS-20 scores showed moderate test-retest reliability and positively correlated with pain catastrophizing, depression, stress, anxiety, and pain intensity. Women and individuals with disabilities reported higher scores. Receiver operating characteristic analysis determined an optimal cutoff score of 52 or above to distinguish highly disabled individuals with 82.35% sensitivity and 58.86% specificity. A minimal detectable change of 26.81 for the PASS-20 total score was identified. The Polish PASS-20 provides valid and reliable scores for measuring pain-related anxiety. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

People with Parkinson’s disease can experience psychological distress and have difficulties accessing face-to-face psychological support due to symptom burden and limited availability of psychological services. Digital options for psychological support can bridge this gap. We have developed an app based on acceptance and commitment therapy (ACT) to support people with Parkinson’s to improve psychological wellbeing. To assess the acceptability of the app and the feasibility of conducting a randomised controlled trial (RCT) to evaluate the effectiveness of using the app to improve wellbeing for people with Parkinson’s. We will conduct a parallel-group randomised controlled feasibility trial comparing a digital app based on ACT (intervention group) to usual care (waitlist control group). We will recruit 60 people with Parkinson’s, 40 to the intervention group and 20 to the control group. Primary feasibility outcomes include recruitment and retention rate, intervention engagement and satisfaction. Secondary outcomes include measures of clinical effectiveness (anxiety and depression), quality of life and cost-effectiveness. Interviews will be conducted to assess acceptability of the app. Primary feasibility outcome data will be analysed descriptively and compared against pre-defined feasibility criteria. Secondary outcomes will be analysed based on an intention-to-treat principle, and a cost-consequence analysis will be used to estimate cost-effectiveness. Interviews will be analysed using a deductive thematic analysis based on the Theoretical Framework of Acceptability. This trial will provide data on the feasibility of conducting a full-scale RCT of the effectiveness and cost-effectiveness of the app to improve psychological wellbeing for people with Parkinson’s disease.

Objective:Ineffective pediatric post-operative pain management increases the risk of Chronic Post-Surgical Pain (CPSP), affecting around 20% of children undergoing major surgery. Psychological predictors of recovery, in both children and their parents, have been identified. However, how these variables change throughout the recovery process remains unclear. The aim of the present study was to investigate the associations of adolescent and parental risk and resilience variables in everyday life, during post-operative recovery, for adolescents undergoing spinal fusion surgery. Methods:Participants were adolescents with Idiopathic Scoliosis (AIS), aged 12-18 years, undergoing spinal fusion surgery, and their parents, recruited at four hospitals in Belgium. Participants completed daily assessments for 7 consecutive days, at 5 time-points, before surgery, and at 3 and 6 weeks, and 6 and 12 months, post-surgery. Diary measures included adolescent and parental pain and recovery variables known to be relevant in the context of pediatric post-operative pain. Network analysis was used to explore correlations between all variables throughout the post-operative recovery process. Results:The sample comprised N=190 participants. Associations were stronger within adolescent and parent variables, than between them. For adolescents, psychological flexibility was associated with positive mood and activity engagement, and pain intensity with pain catastrophizing and activity avoidance. For parents, higher levels of pain-related fear and catastrophizing were related to more parent-to-child instructions to avoid activities. Regarding adolescent-parent between correlations, parental instructions to avoid activities were associated with adolescent physical complaints and activity avoidance, and parent pain catastrophizing was associated with adolescent pain-related fear and catastrophizing. Generally, networks displayed both similarities and differences across post-operative phases. Discussion:The study sample was small in relation to the statistical analyses conducted. Even so, the present findings provide a new perspective on psychological predictors at play in everyday life throughout the pediatric post-operative recovery process, indicating important targets, both clinical and for future investigation.

BACKGROUND:Chronic low back pain (cLBP) typically involves behavior patterns in the development and maintenance of symptoms. Acceptance and Commitment Therapy (ACT) is an evidence-based treatment for chronic pain shown to improve pain-related depression, anxiety, and sleep, as well as pain catastrophizing, pain interference, and levels of reported pain. It has been proven effective when delivered in person or online, but an online therapist-enhanced ACT has not been tested to treat cLBP. This approach may have care delivery advantages while maintaining patient engagement with treatment. OBJECTIVE:Describe the design and implementation of the therapist-supported, online model of ACT that was evaluated in the Biomarking for Evaluating Spine Treatments (BEST) Trial. METHODS:The BEST Trial is a sequential, multiple assignment randomized trial of 4 treatment modalities (exercise and manual therapy; duloxetine; enhanced self-management of pain; and ACT) to inform a precision medicine approach to the treatment of cLBP. The ACT intervention was delivered over the internet via a custom, web-based software platform. The program had three primary components: (1) interactive online sessions consisting of video, audio and self-assessment; (2) therapist sessions via video visits; and (3) ongoing therapist support outside the video visits through a messaging system. DISCUSSION:The ACT intervention addresses the need for mental health care integrated with chronic low back pain treatment. The online ACT treatment program with enhanced therapist support was designed to overcome barriers to multimodal care of CLBP and improve a range of treatment outcomes. CLINICALTRIAL.GOV ID:NCT05396014. REGISTRATION:The BEST Trial is registered in ClinicalTrials.gov (NCT05396014): https://clinicaltrials.gov/study/NCT05396014.

This study investigates whether data from people with endometriosis (n = 58) and fibromyalgia (n = 58) exhibit what is called “ergodicity,” meaning that results from analyses of aggregated group data can be used to support conclusions about the individuals within the groups. The variables studied here are commonly investigated in chronic pain: pain intensity, pain interference, depressive symptoms, psychological flexibility, and pain catastrophizing. Data were collected twice daily for 42 days from each participant and analyzed in 2 ways: as separate cross-sectional group studies using the timepoints as the separate data sets (between-person) and as individual longitudinal studies using each person's time series data (within person). To confirm ergodicity, the results from the 2 analyses should agree. However, this is not what was observed in several respects. The between-person data showed substantially less variability compared with within-person data. This was evident in both the summary statistics involving single variables and in the correlational analyses. Overall, between-person correlations were relatively restricted in range, while within-person correlations varied widely. These findings have potentially profound implications for the field of chronic pain research. Because ergodicity was not found, this raises doubts around the assumption that aggregated data collected from groups can accurately represent the range of individual experiences in chronic pain. These results advocate for a shift toward inclusion of more individual person-focused approaches as an addition to group-based approaches. This shift could lead to more personalized and effective treatments by better capturing and then clarifying the heterogeneous nature of chronic pain, including the processes that underlie it.

Objectives: Persistent symptoms following COVID-19 may adversely impact the general mental health of people with chronic pain, and psychological flexibility may buffer these impacts. However, it remains unclear whether such lasting implications of COVID-19 differ between people with and without chronic pain. This study investigated the relationships between persistent symptoms post-COVID-19, psychological flexibility, and general mental health among people with and without persistent pain during the COVID-19 pandemic in the UK. Methods: A total of 204 adults living in the UK were recruited via social media and completed an online survey, including measures of persistent symptoms, depression (Patient Health Questionnaire-9), anxiety (General Anxiety Disorder-7), insomnia (the Insomnia Severity Index), and psychological flexibility (the Multidimensional Psychological Flexibility Inventory), and were included in the analyses. Results: Participants with persistent pain (n = 70) experienced more-persistent symptoms, poorer general mental health, and a higher level of psychological inflexibility compared with participants without persistent pain (n = 133). Overall, the relationships between persistent physical symptoms, general mental health, and psychological (in)flexibility showed similar patterns in the two groups. Participants with more-persistent physical symptoms experienced significantly poorer general mental health. Furthermore, people with higher levels of psychological inflexibility reported worse general mental health. There was little evidence that psychological (in)flexibility could “buffer” the association between persistent physical symptoms and general mental health. Conclusions: People with chronic pain appear more vulnerable to persistent symptoms and reduced general mental health compared with people without pain. Treatments that reduce psychological inflexibility, such as ACT, may improve outcomes for people with persistent symptoms post-COVID-19.

The Acceptance and Commitment Therapy-Fidelity Measure (ACT-FM) offers a user-friendly assessment of ACT delivery in clinical trials and clinical practice. However, the ACT-FM's measurement properties have not been adequately explored. This study tests whether it performs two key functions: 1) discriminates between therapy sessions delivered with different levels of fidelity to ACT principles; 2) enables reliable scoring. In total, 14 clinicians with experience in ACT were recruited to an online repeated measures experimental study. Using the ACT-FM, they rated three audio clips of simulated therapy sessions with differing levels of ACT fidelity (high, mixed, and low). Audio clips were otherwise identical in terms of clinician-patient dyad, problem (anxiety), and length (15 min). Analyses indicated that ACT-FM scores for Total ACT Consistency and Total ACT Inconsistency domains differed significantly between audio clips and in the expected directions. Intraclass correlation coefficients indicated moderate inter-rater reliability on both domains and there was 80 % agreement among raters at the item level. However, wide confidence intervals suggest imprecision in reliability estimates. These findings suggest that the ACT-FM effectively discriminates between ACT delivered with various levels of fidelity. Yet, further study of interrater reliability is required.

BACKGROUND:Identifying predictors for adherence and clinical response to psychological therapies is essential for improving individual treatment outcomes. OBJECTIVE:To explore predictors of adherence and clinical response among individuals with co-occurring chronic low back pain (CLBP) and depression receiving cognitive behavioral therapy (CBT). METHODS:This study employs a secondary analysis of data from a randomized controlled trial (NCT04140838), including 156 individuals with CLBP plus depressive symptoms who received CBT. Multiple linear regression analyses were conducted to assess the predictive power of sociodemographic, health status, pain-related, and therapy-related variables on adherence and clinical response. Adherence was measured by therapy progress (number of completed sessions) and therapy completion (attendance at least 6 out of 8 sessions). Clinical response was assessed by a clinically relevant reduction in posttreatment pain interference. RESULTS:Older age, higher therapy credibility, and higher education level predicted greater therapy progress, while higher therapy credibility and lower baseline stress levels predicted greater therapy completion. In addition, higher opioid use, baseline pain interference, and baseline depression levels predicted lower clinical response; in contrast, higher behavioral activation levels, older age, and unemployment predicted higher clinical response. CONCLUSION:Therapy credibility, age, and education level are key predictors of adherence, and baseline levels of pain interference, depression, and behavioral activation are key predictors of clinical response. These findings may inform opportunities to develop more effective personalized therapeutic plans for individuals with CLBP and depression.

BACKGROUND:Chronic pain remains a significant health concern, particularly among older adults. Pain acceptance - engaging in valued activities despite pain without attempting to control or avoid it - is thought to buffer against the negative psychosocial impacts of chronic pain. OBJECTIVE:The present study aimed to adapt to Polish and evaluate the psychometric properties of a widely used measure of pain acceptance, namely the Chronic Pain Acceptance Questionnaire (CPAQ). METHODS:Two samples of individuals with chronic pain participated: an online sample (N = 418) and a hospital-recruited sample (N = 148). Confirmatory factor analyses assessed one-factor, two-correlated-factor, and two-orthogonal-factor models for both the original 20-item (CPAQ-20) and the short 8-item (CPAQ-8) versions. RESULTS:In both samples, the results consistently supported a two-factor correlated structure for the Polish CPAQ-8: Activity Engagement (AE) and Pain Willingness (PW). The CPAQ-20 did not show adequate fit. The CPAQ-8 demonstrated acceptable-to-good internal consistency (Cronbach's α = 0.63-0.78 total; 0.75-0.82 subscales) and moderate test-retest reliability (ICC = 0.57). The Minimal Detectable Change for the total score was 9.34 points. In the online sample, CPAQ-8 scores negatively correlated with pain anxiety, pain catastrophizing, anxiety, and depression. Across both samples, total CPAQ-8 and PW scores, but not AE, were negatively associated with pain. Participants reporting activity limitations scored significantly lower on CPAQ-8. Additionally, age was positively correlated with AE scores in both samples. CONCLUSIONS:Overall, the Polish CPAQ-8 exhibits good psychometric properties and is suitable for both research and clinical applications. Future studies should examine its longitudinal validity.

ABSTRACTBackgroundThe Multidimensional Psychological Flexibility Inventory (MPFI) is a measure of all facets of psychological flexibility and inflexibility, potentially important processes of change in psychological treatment for chronic pain. In some contexts, it can be considered too long. The aim of this study was, therefore, to validate a short form MPFI (MPFI‐24P) in a chronic pain sample.MethodsAdults with chronic pain were recruited online (N = 404) for a cross‐sectional survey study. They first completed pain background questions and the MPFI. For examining convergent construct validity and explained variance in pain‐related outcomes, participants also completed the Brief Pain Inventory (BPI) Pain Interference Scale, the Work and Social Adjustment Scale (WSAS) and the Patient Health Questionnaire (PHQ‐9), a depression measure. Data were collected on two occasions, 2 weeks apart. Item response theory (IRT) and confirmatory factor analysis (CFA) were used for selecting the best‐performing items.ResultsIRT parameters were overall adequate, and hierarchical CFA demonstrated a good model fit. Network analysis of the MPFI items indicated that, in general, items intended to measure the same facets were substantially interconnected, more so for the inflexibility items. Temporal stability was adequate, and internal consistency was good. The MPFI‐24P correlated with pain interference, work and social adjustment and depression, with the inflexibility scale better predicting these outcomes. The MPFI‐24P correlated strongly with the full‐length MPFI.ConclusionsThe MPFI‐24P for chronic pain is generally valid and reliable, especially the inflexibility scale. It performs similarly to the full‐length MPFI.SignificanceThis paper contributes with a measure that is both feasible to use in clinical practice and research, while being able to measure all facets of psychological flexibility and inflexibility—psychological processes of change that are important to evaluate in psychological treatment of chronic pain in order to better individualize treatment.

BACKGROUND:Chronic pain affects 20%-30% of the population worldwide, leading to significant distress, disability and financial burden. Pain management strategies focusing on pain reduction have shown limited effects on functioning; however, behavioural treatments aimed at enhancing resilience have demonstrated strong empirical support. Digital solutions offer new opportunities for delivering evidence-based treatments, but evaluation at the individual level is needed. The aim of this study is to examine individual-level treatment effects of a digital behavioural treatment for chronic pain in a heterogeneous sample. METHODS:A study with a single-case experimental design (SCED) was conducted with participants (N = 11) experiencing chronic pain (> 3 months) recruited through healthcare. Participants were randomised at baseline (5-10-day A-phase) and completed a 6-module digital treatment based on learning theory and well-established theories applied to chronic pain (6-8-week B-phase), with weekly therapist contact. Digital diaries, prompted twice daily, tracked psychological flexibility and acceptance, pain-related functioning, pain intensity and well-being. Data were analysed using visual analysis and effect size calculations. RESULTS:N = 11 enrolled and data from n = 10 were analysed (n = 1 refused digital diary, n = 2 partial completers, n = 8 full completers). Pain profiles varied (e.g., chronic migraine, fibromyalgia, lower back pain, etc.). Several participants benefited from the treatment, though results varied across individuals and across outcomes. CONCLUSION:The digital behavioural treatment showed promise in addressing diverse pain profiles and associated functioning. The variability in responses highlights the benefit of using SCED to explore individual-level effects, thus offering a methodological proof-of-concept. Findings support further development, including tailoring to match individual needs. SIGNIFICANCE STATEMENT:This proof-of-concept study provides support for the utility of digital behavioural interventions and individual-level evaluation of treatment effects, highlighting the potential of personalised pain treatments. The findings contribute to the growing body of support for digital solutions as effective and accessible approaches to improve functioning and resilience for people with diverse pain experiences.

Background:Chronic post-surgical pain (CPSP) affects ≈20% of children after major surgery, and the condition is associated with functional disability and ill-health. Psychological flexibility (PF) and parental factors have been shown to predict CPSP in youth following spinal fusion surgery. However, the daily dynamics of these processes throughout post-surgical recovery remain unknown. This study aimed at exploring how PF fluctuates in everyday life for youths undergoing spinal fusion surgery, and to investigate the associations between parental responses and adolescent PF. Methods:Adolescents with Idiopathic Scoliosis (AIS), aged 12-18 years, undergoing spinal fusion surgery at four hospitals in Belgium, and their parents, completed diaries, measuring adolescent PF and parental responses (including instructions to avoid or engage in activities, parental protective behavior, and parental pain catastrophizing) for 7 days, at five phases: before surgery (T0), at 3 (T1) and 6 weeks (T2), and 6 (T3) and 12 (T4) months, post-surgery. A single-case approach with aggregated results was used, including Tau-U calculations and cross-lagged correlations. Results:In total, data from 47 adolescents and seven parents were analyzed. Substantial within- and between-person variability characterized the patterns of adolescent PF. Cross-lagged correlations showed bidirectional relationships, demonstrating that parental responses predicted adolescent PF, and that adolescent PF, similarly, predicted parental responses. Discussion:The results reveal the complex dynamics of PF among adolescents following surgery, and that parent-adolescent patterns after surgery may vary across both individuals and time. These findings also emphasize the need for idiographic pain research and individual-level assessments as well as person-centered treatments in clinical practice.