A Comparative Meta-Analysis of Unidisciplinary Psychology and Interdisciplinary Treatment Outcomes Following Acceptance and Commitment Therapy for Adults with Chronic Pain

Effectiveness of psychological interventions to decrease cognitive fusion in patients with chronic pain: A systematic review and meta-analysis

OBJECTIVE

While there is sufficient evidence of Acceptance and Commitment Therapy's effectiveness in allowing patients to deal with chronic pain, the effectiveness in cognitive fusion, one of the six core components of the Psychology Flexibility Model, has yet to be established. The aim of this article is to assess whether psychological interventions decrease cognitive fusion.

METHODS

The Web of Science, SCOPUS, Medline, and PsycINFO databases were searched for primary studies up to June 2024. Studies with a cognitive fusion measure in which chronic pain patients received a psychological intervention were included. A methodological quality scale was applied to the selected studies and the average effect sizes (Hedges g) were calculated.

RESULTS

This review included 18 articles with 24 studies (19 pre-post/follow-up studies and five randomized control trials). Cognitive fusion decreased significantly after the intervention. The effect sizes were small/medium at post-test, g = -0.39, p < .001, 95% CI [-0.52, -0.26]; and medium at long-term follow-up, g = -0.55, p < .001, 95% CI [-0.74, -0.36]. A similar tendency was found for studies with RCTs at post-test, g = -0.61, p = .006, 95% CI [-1.05, -0.17], short-term follow-up, g = -0.79, p < .001, 95% CI [-1.18, -0.40] and long-term follow-up, g = -0.58, p = .003, 95% CI [-0.95, -0.20]). Moderator variables such as unemployment, gender, pain intensity, level of depression before the intervention, and duration and intervention modality were identified.

CONCLUSION

Psychological interventions tended to decrease cognitive fusion in chronic pain patients. Nonetheless, more clinical trials are needed to establish the role of cognitive fusion in psychological flexibility.

Impact of healthcare interventions on distress following acute musculoskeletal/orthopaedic injury: a scoping review of systematic reviews

BACKGROUND

Musculoskeletal injuries can cause distress, and distress is associated with delayed recovery. Numerous interventions have been developed to facilitate recovery from injury, and several systematic reviews evaluate the efficacy of these interventions for reducing psychological distress.

OBJECTIVES

This scoping review aims to map the synthesised evidence for the relationship between treatment interventions and distress-related outcomes following acute injury. The objectives were (1) to describe the types of interventions that have been evaluated in relation to distress-related outcomes following accidental injury, (2) to examine the scope of distress-related outcomes that have been measured in relation to these interventions and (3) to explore the range of clinical professions that deliver these interventions.

DESIGN

We searched nine electronic databases and grey literature (to 21 April 2022). We included any systematic review reporting on the relationship between interventions delivered in the time following injury and distress-related outcomes. Data relevant to the specific objectives of this scoping review were extracted and described using narrative synthesis.

RESULTS

From 8412 systematic reviews imported for screening, 8266 unique records were screened. 179 were selected for full-text review. 84 systematic reviews were included in the study. Interventional types were pharmacological, psychological, exercise based, physical/manual therapies, virtual reality based, multimodal and workplace based. Interventions were delivered digitally, face to face and using virtual reality by a variety of healthcare professionals, including doctors, nurses, psychologists and physiotherapists. The most frequently reported distress-related variables included anxiety, depression, post-traumatic stress disorder diagnosis.

CONCLUSION

A wide range of interventions may help to mitigate distress following acute accidental musculoskeletal or orthopaedic injury. Even interventions that were not designed to reduce distress were found to improve distress-related outcomes. In view of the important role of distress in recovery from injury, it is recommended that distress-related variables are measured as core outcomes in the evaluation of treatments for acute injuries.

Does Platelet-Rich Plasma Deserve a Role in Accelerating the Recovery of Reflex Sympathetic Dystrophy Following Distal Radius Fracture?

Introduction

This study was to evaluate the efficacy of multiple platelet-rich plasma injections in reflex sympathetic dystrophy following distal radius fracture after previous various treatments have failed.

Materials and methods

This comparative prospective study was designed for 64 patients of reflex sympathetic dystrophy developed following distal radius fracture, from January 2009 to December 2020 were enrolled in this study. This cohort of patient was given either four multiple subcutaneous platelet-rich plasma injections at weekly interval (n = 32) or two injections in a month with 15 days interval (n = 32). The primary outcome measure assessed with patient rated wrist evaluation questionnaire score. The secondary outcome was a visual analogue scale pain score. The final follow up was at 2 years. p ≤ 0.05 is considered statistically.

Results

The patient rated wrist evaluation score for usual and specific activities and EQ-VAS for pain level showed statistically significant greater improvement in group A (42 ± 21%) compared to group B (19 ± 24%), (p = 0.37). Patients also had improvement in wrist movements with no statistically significant differences in both groups. The standard difference in means of all three functional scores was almost similar between both groups A and B (standard difference in means = 0.032; 95% CI 0.236-0.830; p = 0.495), considered clinically meaningful.

Conclusion

This study results suggest autologous platelet-rich plasma injections seem to be safe, cost effective, efficacious algorithm treatment for reflex sympathetic dystrophy following distal radius fracture patients where previous treatments have failed.

Feasibility of Web-Based Single-Session Empowered Relief in Patients With Chronic Pain Taking Methadone or Buprenorphine: Protocol for a Single-Arm Trial

BACKGROUND

Chronic pain affects tens of millions of US adults and continues to rise in prevalence. Nonpharmacologic behavioral pain treatments are greatly needed and yet are often inaccessible, particularly in settings where medication prescribing is prioritized.

OBJECTIVE

This study aims to test the feasibility of a live-instructor, web-based 1-session pain relief skills class in an underserved and potentially at-risk population: people with chronic pain prescribed methadone or buprenorphine either solely for pain or for comorbid opioid use disorder (OUD).

METHODS

This is a national, prospective, single-arm, uncontrolled feasibility trial. The trial is untethered from medical care; to enhance participants' willingness to join the study, no medical records or drug-monitoring records are accessed. At least 45 participants will be recruited from outpatient pain clinics and from an existing research database of individuals who have chronic pain and are taking methadone or buprenorphine. Patient-reported measures will be collected at 6 time points (baseline, immediately post treatment, 2 weeks, and months 1-3) via a web-based platform, paper, or phone formats to include individuals with limited internet or computer access and low literacy skills. At baseline, participants complete demographic questions and 13 study measures (Treatment Expectations, Body Pain Map, Medication Use, Pain Catastrophizing Scale [PCS], Patient-Reported Outcomes Measurement Information System [PROMIS] Measures, and Opioid Craving Scale). Immediately post treatment, a treatment satisfaction and acceptability measure is administered on a 0 (very dissatisfied) to 10 (completely satisfied) scale, with 3 of these items being the primary outcome (perceived usefulness, participant satisfaction, and likelihood of using the skills). At each remaining time point, the participants complete all study measures minus treatment expectations and satisfaction. Participants who do not have current OUD will be assessed for historical OUD, with presence of OUD (yes or no), and history of OUD (yes or no) reported separately. Feasibility threshold is set as an overall group treatment satisfaction rating of 8 of 10. In-depth qualitative interviews will be conducted with about 10 participants to obtain additional data on patient perceptions, satisfactions, needs, and wants. To assess preliminary efficacy, we will examine changes in pain catastrophizing, pain intensity, pain bothersomeness, sleep disturbance, pain interference, depression, anxiety, physical function, global impression of change, and opioid craving at 1 month post treatment.

RESULTS

This project opened to enrollment in September 2021 and completed the recruitment in October 2023. The data collection was completed in February 2024. Results are expected to be published in late 2024.

CONCLUSIONS

Results from this trial will inform the feasibility and preliminary efficacy of Empowered Relief in this population and will inform the design of a future randomized controlled trial testing web-based Empowered Relief in chronic pain and comorbid OUD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05057988; https://clinicaltrials.gov/study/NCT05057988.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/53784.

Acceptance and Commitment Therapy for Chronic Pain: An Overview of Systematic Reviews with Meta-Analysis of Randomized Clinical Trials

This overview of reviews aimed to summarize the evidence from systematic reviews and meta-analyses of randomized clinical trials of the efficacy of acceptance and commitment therapy (ACT) for adults with chronic pain in relation to pain intensity, pain-related functioning, quality of life, and psychological factors. The Cumulative Index of Nursing and Allied Health Literature (CINAHL), Embase, PsycINFO, PubMed, and the Cochrane Library databases were searched from inception to July 2, 2023. AMSTAR 2 was used to assess the methodological quality of systematic reviews. The overlap among reviews was calculated. Nine reviews comprising 84 meta-analyses of interest were included. At post-treatment, some meta-analyses mainly showed that ACT can reduce depression symptoms, anxiety symptoms, psychological inflexibility, and pain catastrophizing; and can improve mindfulness, pain acceptance, and psychological flexibility. At three-month follow-up, ACT can reduce depression symptoms and psychological inflexibility, as well as improve pain-related functioning and psychological flexibility. At six-month follow-up, ACT can improve mindfulness, pain-related functioning, pain acceptance, psychological flexibility, and quality of life. At six-twelve-month follow-up, ACT can reduce pain catastrophizing and can improve pain-related functioning. Some methodological and clinical issues are identified in the reviews, such as a very high overlap between systematic reviews, the fact that the certainty of the evidence is often not rated and specific details needed to replicate the interventions reviewed are often not reported. Overall, however, randomized clinical trials and systematic reviews show that ACT can improve outcomes related to chronic pain (eg, pain-related functioning). Future systematic reviews should address the methodological and clinical concerns identified here to produce higher-quality findings. PERSPECTIVE: Despite certain methodological and clinical issues, randomized clinical trials and systematic reviews of ACT appear to show that it can improve outcomes related to chronic pain (eg, psychological factors).

Treatment of last resort? Psychological therapy seeking in chronic pain patients

OBJECTIVE

Our goal was to assess how many chronic pain patients seek psychological treatment for their condition and what psychological and demographic characteristics are associated with that decision.

METHODS

The association between pain intensity, quality of life and psychological treatment seeking was tested in two hypothetical models which differed according to beliefs about either external or internal control over pain.

RESULTS

A minority of patients had experience with psychological treatment of chronic pain. Patients who had that experience were younger, suffered from more intense pain, and applied many more coping strategies than patients who never tried this kind of treatment. Intense pain and low quality of life motivated chronic pain patients to seek psychological treatment only if they believed that doctors could control their pain.

DISCUSSION

The study results stress the importance of diversifying the methods used to treat chronic pain and educating patients about the benefits of psychological treatment. Low numbers of chronic pain patients who take advantage of psychological treatment indicate that encouragement from medical professionals might be necessary.

Effect of acceptance and commitment therapy for depressive disorders: a meta-analysis

OBJECTIVE

To systematically evaluate the effect of Acceptance and Commitment Therapy (ACT) on depressive disorders.

METHODS

The electronic databases of Web of Science Core Collection, Pubmed, EMBASE, Cochrane Library, PsycInfo, CNKI, Wanfang and Weipu were used to select relevant publications. Screening, data extraction, and quality assessment were undertaken following PRISMA guidelines for preferred reporting of systematic reviews and meta-analysis. RevMan5.4 was used for meta-analysis.

RESULTS

11 studies with a total of 962 patients were included. Random-effects model analysis showed that ACT could effectively reduce the level of depressive symptoms in patients with depressive disorders (SMD = - 1.05, 95% CI: - 1.43-- 0.66, P < 0.00001), improve psychological flexibility (MD = 4.84, 95% CI: 2.70-6.97, P < 0.00001), and have good maintenance effect (SMD = - 0.70, 95% CI: - 1.15-- 0.25, P = 0.002). All differences were statistically significant.

CONCLUSIONS

ACT not only improves depressive symptoms and psychological flexibility, but also has a good maintenance effect, and it is particularly effective in Chinese patients. Large randomized controlled trials are needed to validate the findings from this meta-analysis.

Interdisciplinary pain rehabilitation and sexual functioning: Treatment outcomes and patient preferences

BACKGROUND/OBJECTIVE

Sexual dysfunction is common for patients experiencing chronic pain. Prior research is limited on how treatment for chronic pain affects patients' sexual functioning. This study reports pre-/post-treatment measures of self-reported sexual functioning among individuals presenting for chronic pain treatment at an interdisciplinary pain rehabilitation program (IPRP) and reports patient treatment preferences.

METHOD

This study uses detailed treatment measures across multiple domains of sexual functioning to describe the prevalence and correlates of self-reported sexual functioning among individuals with chronic pain presenting for and discharging from treatment at an IPRP (N = 71). Domains include sexual interest, satisfaction with sexual functioning, vaginal lubrication, vaginal discomfort, and erectile function. Patients also completed a multiple-choice treatment preferences questionnaire created for this study.

RESULTS

Results from this study show a high prevalence of sexual dysfunction in chronic pain populations (51.5%) and show no significant difference in sexual functioning after completing outpatient treatment, except for a significant improvement in sexual satisfaction for males only. Results from the patient treatment preferences questionnaire indicate that most patients (83.3%) thought their pain was important to address within the context of an IPRP; however, many patients (58.7%) did not think their treatment addressed sexual functioning. In addition, many patients (34%) would prefer to discuss sexual functioning with their primary care provider or pelvic floor physical therapist.

CONCLUSION

Findings demonstrate that usual multidisciplinary pain management treatment is not sufficient to address patients' concerns with sexual functioning. Additional creative strategies will need to be studied on how to best treat these overlapping problems. Implications and future research directions are discussed.

A self-guided Internet-based intervention for individuals with chronic pain and depressive symptoms: study protocol of a randomized controlled trial

BACKGROUND

Despite the existence of evidence-based therapy options for the treatment of chronic pain and comorbid depressive symptoms (e.g., CBT), many individuals remain untreated. Treatment gaps result from a lack of specialists, patient fear of stigmatization, or patient immobility. Internet-based self-help interventions could serve as an anonymous and flexible alternative treatment option. In a pilot study, chronic pain patients with comorbid depressive symptoms who used a generic Internet-based depression program showed a significant reduction in depressive symptoms (but not pain symptoms) compared to a waitlist control group. Based on these findings, we developed the low-threshold, anonymous, and cost-free Internet-based self-help intervention Lenio that is tailored to the specific needs of chronic pain patients with comorbid depressive symptoms. Lenio is accompanied by the smartphone application (app) COGITO designed to increase therapeutic success. With Lenio and COGITO addressing both chronic pain and depressive symptoms, the trial aims to increase treatment effects of online interventions for chronic pain patients by reducing both depressive symptoms and pain.

METHODS

The effectiveness of the Internet-based self-help intervention and accompanying smartphone app will be evaluated in a randomized controlled trial (RCT). A total of 300 participants will be randomized into an intervention group (Lenio/COGITO), an active control group (depression-focused smartphone app), or a waitlist control group. Assessments will be done at baseline, after an 8-week intervention period (post), and after 16 weeks (follow-up). The primary outcome is the post-assessment reduction in "pain impairment" (mean value of impairment in daily life, free time, and work) as assessed by the DSF (German pain questionnaire). Secondary outcomes will include the reduction in depressive symptoms as well as in the severity of pain.

DISCUSSION

Lenio is one of the first Internet-based interventions to reduce chronic pain and depression that will be empirically evaluated. Internet-based interventions could offer a promising alternative to conventional face-to-face psychotherapy in the treatment of chronic pain patients. The primary objective of the current study is to add essential insight into the feasibility, effectiveness, and acceptance of Internet-based interventions for people with chronic pain and depressive symptoms.

TRIAL REGISTRATION

DRKS-ID DRKS00026722, Registered on October 6th, 2021.

Are Prayer-Based Interventions Effective Pain Management Options? A Systematic Review and Meta-analysis of Randomized Controlled Trials

This review examined the effects of private and communal participatory prayer on pain. Nine databases were searched. Six randomized controlled trials were included. For private prayer, medium to large effects emerged for 67% to 69% of between-group comparisons; participants in the prayer condition reported lower pain intensity (0.59 < d < 26.17; 4 studies) and higher pain tolerance (0.70 < d < 1.05; 1 study). Pre- to post-intervention comparisons yielded medium to large effects (0.76 < d < 1.67; 2 studies); pain intensity decreased. Although firm conclusions cannot be made because meta-analysis was based on only two studies, the analysis suggested prayer might reduce pain intensity (SMD = - 2.63, 95% CI [- 3.11, - 2.14], I = 0%). (PROSPERO: CRD42020221733).

Online ACT intervention for fibromyalgia: An exploratory study of feasibility and preliminary effectiveness with smartphone-delivered experiential sampling assessment

INTRODUCTION

Acceptance and commitment therapy (ACT) is an effective treatment for chronic pain conditions. ACT seeks to produce clinical change by enhancing Psychological Flexibility (PF). This exploratory (feasibility and preliminary effectiveness) study presents a pilot application of an online ACT group intervention for fibromyalgia (FM) with an extensive Experiential Sampling (ES) assessment of outcome and process variables via smartphone.

METHOD

5-weekly ACT online group sessions were applied to 9 female FM patients. Questionnaire-based assessments of several clinical outcomes and PF processes were conducted pre- and post-intervention, and at 6-month follow-up. Extensive (6 weeks pre- and 6 weeks post-intervention) smartphone-delivered ES was implemented to gather process and outcome data in the patients' usual contexts. Clinically significant change was evaluated both at the group level and individually.

RESULTS

This treatment format appears to be feasible and acceptable to participants, with good adoption and completion rates (75 %) and excellent rates of treatment completion and clinical adherence (100 %). Participants showed significant reductions in affective pain, distress and biopsychosocial impact of FM both post-intervention and at 6-month follow-up (as measured with questionnaires), as well as significant improvements in satisfaction with actions and emotional discomfort (as measured through ES). Multilevel regression analyses indicated that PF-related processes assessed through ES had a significant impact on clinical outcomes and predicted the impact of FM at the 6-month follow-up.

CONCLUSIONS

A brief online group ACT intervention for FM was both feasible and acceptable to participants. Also, there was preliminary evidence of effectiveness in enhancing pain-related PF and producing clinical benefits in FM.

On the body-mind nexus in chronic musculoskeletal pain: A scoping review

BACKGROUND AND OBJECTIVE

Bodily experience disturbances are frequent among chronic musculoskeletal pain patients and associated with important pain-related psychosocial outcomes (e.g., disability, quality of life). However, the relationship between bodily experience and the psychological dimensions of chronic pain (e.g., affective, cognitive) has only recently garnered attention. This scoping review aimed to identify trends and gaps in research on the nexus between body awareness, body image, and body schema, and psychological processes/outcomes in adults with chronic musculoskeletal pain to inform future directions for research and practice.

DATABASES AND DATA TREATMENT

This study was guided by Arksey and O'Malley's guidelines and PRISMA-ScR recommendations. Keywords related to body awareness/body image/body schema and pain were searched on PsycInfo and PubMed from database inception until 16 February 2021; 2045 articles were screened, and 41 met the inclusion criteria (i.e., primary quantitative studies investigating body awareness/body image/body schema in relation to pain-related psychological outcomes/processes in chronic musculoskeletal pain).

RESULTS

The referred bodily experience constructs have been inconsistently defined. Body awareness was the most investigated construct, with consistent operationalization strategies. The links between body schema/body image and pain-related psychological processes/outcomes are still under-investigated. Most studies examined the role of bodily experience as a correlate/predictor of psychological outcomes/processes; overall, a better relationship with one's own body was associated with better pain-related psychological outcomes/processes.

CONCLUSIONS

Our findings emphasize the relevance of further investigating body-mind relations in musculoskeletal pain and the development of therapies designed to improve the bodily experience within multidisciplinary treatment programmes. Suggestions for future research are discussed.

SIGNIFICANCE

This scoping review identifies trends/gaps in current research on the relationship between body awareness/body image/body schema and pain-related psychological processes/outcomes in adults with musculoskeletal pain. Overall, findings suggest that better bodily experiences are associated to lower fear-avoidance beliefs, better self-regulation strategies and better chronic pain adjustment, being important targets in pain management interventions. Nonetheless, the results also emphasize the need to further investigate the causal relationships and other outcomes related to psychological resilience, as well as to develop gold standard treatments focused on bodily experience.

Profiles of Pain Acceptance and Values-Based Action in the Assessment and Treatment of Chronic Pain

Pain acceptance and values-based action are relevant to treatment outcomes in those with chronic pain. It is unclear if patterns of responding in these two behavioral processes can be used to classify patients into distinct classes at treatment onset and used to predict treatment response. This observational cohort study had two distinct goals. First, it sought to classify patients at assessment based on pain acceptance and values-based action (N = 1746). Second, it sought to examine treatment outcomes based on class membership in a sub-set of patients completing an interdisciplinary pain rehabilitation program of Acceptance and Commitment Therapy for chronic pain (N = 343). Latent profile analysis was used in the larger sample to identify three distinct patient classes: low acceptance and values-based (AV) action (Low AV; n = 424), moderate acceptance and values-based action (Moderate AV; n = 983) and high acceptance and values-based action (High AV; n = 339). In the smaller treated sample, participants in the Low AV and Moderate AV class demonstrated improvements across all outcome variables, whereas those in the High AV class did not. These findings support the role of pain acceptance and values-based action in those with chronic pain.

Opioid Prescribing Patterns for Acute Pain

PURPOSE

The current study aimed to identify patients presenting with acute pain who may be at risk for a complicated trajectory, via identifying clusters of early opioid prescribing patterns.

METHODS

National Veterans Affairs administrative data were utilized to build a cohort of outpatients with acute pain presentations and no more than minimal opioid use in the prior year. Latent Class Analyses (LCA) identified clusters of early opioid prescribing patterns. Risk of progression to long-term opioid use was contrasted between LCA clusters using log-binomial regression, adjusting for confounding variables.

RESULTS

The 2018 cohort included N = 191,283. Among the 27,890 who received an initial opioid prescription, LCA classes were identified using: first supply day, total days dispensed across 30 days, opioid type, dose, and number of prescriptions across the first 30 days. In the three-class model: class 1 indicated an immediate, low-dose, brief supply; class 2 included delayed, low-dose and longer duration prescriptions; and class 3 included delayed high-dose, and moderate duration. Adjusted relative risk ratios for progression to long-term opioid use in the following year were 3.33 (95% CI: 2.71-4.10) for class 1 (absolute risk 1.1%); 7.76 (95% CI: 6.69-8.99) for class 2 (3.1%); and 6.81 (95% CI: 5.72 - 8.12) for class 3 (2.4%); compared to patients who did not receive an acute opioid prescription (0.3%).

CONCLUSIONS

These clusters of acute opioid prescribing could facilitate identification of patients who may benefit from enhanced pain care earlier in the pain trajectory and decrease future reliance on long-term opioid therapy.

Interventions for Depressive Symptoms in People Living with Chronic Pain: A Systematic Review of Meta-Analyses

OBJECTIVE

This review investigated the effectiveness of clinical interventions on depressive symptoms in people with all types of chronic pain.

METHODS

We searched seven electronic databases and reference lists on September 15, 2020, and included English-language, systematic reviews and meta-analyses of trials that examined the effects of clinical interventions on depressive outcomes in chronic pain. Two independent reviewers screened, extracted, and assessed the risk of bias. PROSPERO registration: CRD42019131871.

RESULTS

Eighty-three reviews were selected and included 182 meta-analyses. Data were summarized visually and narratively using standardized mean differences with 95% confidence intervals as the primary outcome of interest. A large proportion of meta-analyses investigated fibromyalgia or mixed chronic pain, and psychological interventions were most commonly evaluated. Acceptance and commitment therapy for general chronic pain, and fluoxetine and web-based psychotherapy for fibromyalgia showed the most robust effects and can be prioritized for implementation in clinical practice. Exercise for arthritis, pharmacotherapy for neuropathic pain, self-regulatory psychotherapy for axial pain, and music therapy for general chronic pain showed large, significant effects, but estimates were derived from low- or critically low-quality reviews.

CONCLUSIONS

No single intervention type demonstrated substantial superiority across multiple pain populations. Other dimensions beyond efficacy, such as accessibility, safety, cost, patient preference, and efficacy for non-depressive outcomes should also be weighed when considering treatment options. Further effectiveness research is required for common pain types such as arthritis and axial pain, and common interventions such as opioids, anti-inflammatories and acupuncture.

Where is my arm? Investigating the link between complex regional pain syndrome and poor localisation of the affected limb

Background

Anecdotally, people living with Complex Regional Pain Syndrome (CRPS) often report difficulties in localising their own affected limb when it is out of view. Experimental attempts to investigate this report have used explicit tasks and yielded varied results.

Methods

Here we used a limb localisation task that interrogates implicit mechanisms because we first induce a compelling illusion called the Disappearing Hand Trick (DHT). In the DHT, participants judge their hands to be close together when, in fact, they are far apart. Sixteen volunteers with unilateral upper limb CRPS (mean age 39 ± 12 years, four males), 15 volunteers with non-CRPS persistent hand pain (‘pain controls’; mean age 58 ± 13 years, two males) and 29 pain-free volunteers (‘pain-free controls’; mean age 36 ± 19 years, 10 males) performed a hand-localisation task after each of three conditions: the DHT illusion and two control conditions in which no illusion was performed. The conditions were repeated twice (one for each hand). We hypothesised that (1) participants with CRPS would perform worse at hand self-localisation than both the control samples; (2) participants with non-CRPS persistent hand pain would perform worse than pain-free controls; (3) participants in both persistent pain groups would perform worse with their affected hand than with their unaffected hand.

Results

Our first two hypotheses were not supported. Our third hypothesis was supported —when visually and proprioceptively encoded positions of the hands were incongruent (i.e. after the DHT), relocalisation performance was worse with the affected hand than it was with the unaffected hand. The similar results in hand localisation in the control and pain groups might suggest that, when implicit processes are required, people with CRPS’ ability to localise their limb is preserved.

Process-outcome associations in an interdisciplinary treatment for chronic pain and comorbid mental disorders based on Acceptance and Commitment Therapy

OBJECTIVE

Numerous studies support the effectiveness of Acceptance and Commitment Therapy (ACT) for chronic pain, yet little research has been conducted about its underlying mechanisms of change, especially regarding patients with comorbid mental disorders. The present investigation addressed this issue by examining associations of processes targeted by ACT (pain acceptance, mindfulness, psychological flexibility) and clinical outcomes (pain intensity, somatic symptoms, physical health, mental health, depression, general anxiety).

SUBJECTS

Participants were 109 patients who attended an ACT-based interdisciplinary treatment program for chronic pain and comorbid mental disorders in a routine care psychiatric day hospital.

METHODS

Pre- to post-treatment differences in processes and outcomes were examined with Wilcoxon signed-rank tests and effect size r. Associations between changes in processes and changes in outcomes were analyzed with correlation and multiple regression analyses.

RESULTS

Pre- to post-treatment effect sizes were mostly moderate to large (r between |0.21| and |0.62|). Associations between changes in processes and changes in outcomes were moderate to large for both, bivariate correlations (r between |0.30| and |0.54|) and shared variances accounting for all three processes combined (R2 between 0.21 and 0.29).

CONCLUSION

The present investigation suggests that changes in pain acceptance, mindfulness and psychological flexibility are meaningfully associated with changes in clinical outcomes. It provides evidence on particular process-outcome associations that had not been investigated in this way before. The focus on comorbid mental disorders informs clinicians about a population of chronic pain patients that often has a severe course of illness and has seldom been studied.