Chronic Pain (CP) is a condition characterized by pain lasting or recurring for more than three months, often accompanied by emotional distress and difficulties in daily functioning. CP represents a major burden for individuals and healthcare systems due to its impact on quality of life, healthcare utilization, and work productivity. Traditional treatments, such as pharmacological and surgical approaches, frequently provide insufficient relief, highlighting the need for complementary interventions. Among psychological approaches, Acceptance and Commitment Therapy (ACT) has shown promising results for CP management. ACT aims to increase psychological flexibility by helping individuals accept pain as part of their experience while engaging in meaningful, value-based activities. Rather than focusing exclusively on symptom reduction, ACT promotes emotional well-being, functioning, and quality of life. However, access to psychological interventions remains limited because of barriers such as long waiting lists, geographical distance, physical limitations, stigma, and limited availability of trained professionals. Digital health interventions, particularly internet-delivered self-help programs, may help overcome these barriers by providing flexible, accessible, and cost-effective support. Previous research suggests that ACT can be effectively adapted to online formats, allowing broader dissemination and increased accessibility for individuals with CP. The present study aims to evaluate the effectiveness of a guided internet-delivered ACT-based self-help intervention for individuals with CP. The intervention seeks to support pain acceptance, improve quality of life, and promote engagement in valued activities. The study will also explore potential psychological mechanisms underlying treatment outcomes and assess the cost-effectiveness of the intervention to evaluate its potential implementation within public healthcare systems.
Chronic Pain (CP) is a persistent condition characterized by emotional distress and functional impairment that is not better explained by another diagnosis. Its multifactorial nature includes biological, psychological, and social components that interact to maintain and exacerbate symptoms. Psychological processes such as pain-related fear, avoidance behaviors, catastrophizing, and reduced engagement in valued activities contribute to disability and diminished quality of life. Pharmacological and surgical treatments alone frequently provide insufficient improvement, underscoring the relevance of psychological interventions. Acceptance and Commitment Therapy (ACT) is designed to improve psychological flexibility by promoting willingness to experience pain-related distress while pursuing personally meaningful behaviors. ACT-based interventions have shown effectiveness in addressing emotional and behavioral responses to pain, reducing disability, and improving overall functioning. Due to its modularity and transdiagnostic focus, ACT can be adapted for a wide range of CP presentations and is suitable for digital delivery. Internet-based interventions (IBIs) are increasingly implemented to improve accessibility to psychological treatment. Digital delivery may reduce barriers related to mobility limitations, geographical distance, waiting lists, stigma, and limited availability of trained clinicians. Guided IBIs allow patients to engage with structured therapeutic content at their own pace, while also receiving support from a therapist. Internet-based ACT programs have demonstrated promising effects on pain acceptance, emotional functioning, behavioral flexibility, and pain-related disability. The present randomized controlled trial aims to evaluate the effectiveness and cost-effectiveness of MobACT, a guided internet-based ACT intervention adapted for the Italian population. The program consists of seven weekly modules addressing core ACT processes, including acceptance, defusion, values clarification, and committed action. The intervention is delivered through the secure, research-oriented iTerapi platform, which provides access to treatment content, therapist communication, and assessment tools. Participants receive weekly notifications when new material is available and reminder messages if modules are not completed. Participants complete baseline, post-treatment, and follow-up assessments through the platform. During treatment, additional weekly monitoring collects information on sleep quality and changes in pharmacological therapy for pain management. A subset of participants will take part in semi-structured qualitative interviews to explore their subjective treatment experience, usability perceptions, and acceptability of the digital format. Interview data will undergo thematic analysis. Data management follows strict procedures to ensure confidentiality, integrity, and secure storage. All participant information is de-identified and stored on encrypted servers with access restricted to authorized study personnel. Statistical analyses will compare outcomes between groups and explore potential mediators and moderators of treatment effects. Cost-effectiveness will be evaluated from both healthcare and societal perspectives, accounting for resource utilization, productivity losses, and implementation costs. The intervention is expected to improve acceptance of chronic pain, psychological flexibility, coping behaviors, sleep quality, and overall quality of life, while reducing pain intensity, interference, catastrophizing, and emotional distress. Insights gained from the trial will contribute to understanding the mechanisms of change in internet-delivered ACT programs and inform the development of scalable psychological interventions for chronic pain.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
140
Participants allocated to the experimental group will be asked to complete one module per week, each based on the core principles of Acceptance and Commitment Therapy (ACT). The treatment program consists of seven modules delivered weekly over a total duration of seven weeks. The content of the modules will cover the following topics: 1. Creative hopelessness 2. Willingness and acceptance of pain 3. Defusion from negative thoughts 4. Committed action and values 5. Values and goal setting 6. Willingness exercises 7. Maintenance of learned strategies.
Alma Mater Studiorum of Bologna
Bologna, Italy
RECRUITINGCatholic University of Sacred Heart
Milan, Italy
RECRUITINGUniversity of Verona
Verona, Italy
RECRUITINGUniversity of Linkoping
Linköping, Sweden
RECRUITINGChronic Pain Acceptance
The Chronic Pain Acceptance Questionnaire (CPAQ) (20 items) is used to assess acceptance of chronic pain. Each item is rated on a scale from 0 ("Never true") to 6 ("Always true"), where the respondent indicates their level of agreement with each statement. The CPAQ is composed of two subscales: Activity Engagement (AE) and Pain Willingness (PW). To calculate the CPAQ score, the items corresponding to each subscale are summed to obtain a score for each domain. The total score, ranging from 0 to 120, is the sum of the two subscale scores. Higher scores indicate greater levels of pain acceptance. The Activity Engagement (AE) subscale measures the extent to which individuals continue to engage in daily activities regardless of their pain, while the Pain Willingness (PW) subscale assesses the extent to which individuals perceive that avoiding or controlling pain is an ineffective strategy.
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Pain Intensity and Pain Interference
The Brief Pain Inventory - Italian version (BPI-I) (10 items) consists of two subscales. The first subscale assesses pain intensity using four Numerical Rating Scales, ranging from 0 ("no pain") to 10 ("pain as bad as you can imagine"), which measure current pain, worst pain, least pain, and average pain experienced over the past 24 hours. The second subscale evaluates pain interference with various aspects of daily life, including general activity, walking, mood, sleep, work, relationships with others, and enjoyment of life. These are also rated on Numerical Rating Scales from 0 ("does not interfere") to 10 ("completely interferes"). The Italian version of the BPI has shown good internal consistency (Cronbach's alpha = 0.80), stability (rho = 0.789, p \< 0.001), excellent inter-rater reliability (k = 0.945), and good homogeneity (alpha = 0.8).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Quality of Life
The EuroQol-5D-3L (EQ-5D-3L) is a standardized instrument developed to assess quality of life. The questionnaire consists of two parts. The first part includes five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, each rated on three levels of severity, from 1 ("no problems") to 3 ("extreme problems"). The second part features a Visual Analogue Scale (EQ VAS) that assesses the respondent's current perceived health on a scale from 0 ("worst imaginable health") to 100 ("best imaginable health"). The Italian version of the EQ-5D-3L has shown good reliability, with a Cronbach's alpha coefficient of 0.73.
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Sleep Quality
The Mini Sleep Questionnaire (MSQ) (10 items) evaluates sleep quality by assessing both sleep and wakefulness factors. Each item is rated on a Numerical Rating Scale (NRS) from 1 ("Never") to 7 ("Always"), referring to the respondent's experience over the past week. The Italian version of the MSQ has demonstrated good internal consistency (Cronbach's alpha = 0.77), good test-retest reliability (ICC = 0.82), and factor analysis confirmed two dimensions (sleep and wakefulness) with Cronbach's alpha = 0.75 for both. Optimal cut-off values were identified (\>16 for sleep and \>14 for wakefulness), with an area under the curve greater than 0.80.
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Central Sensitization
The Central Sensitization Inventory (CSI) (35 items) measures current health symptoms related to central sensitization, yielding a total score ranging from 0 to 100. Items are rated on a scale from "never" (0) to "always" (4), with higher scores indicating greater presence of central sensitization symptoms. A cut-off score of 40 has demonstrated good sensitivity and specificity for identifying patients with central sensitization syndromes. The Italian version of the CSI has shown good internal consistency (Cronbach's alpha = 0.87), ranging from 0.86 to 0.87 when individual items are removed.
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Pain Catastrophizing
The Pain Catastrophizing Scale (PCS) (13 items) is used to assess the level of catastrophizing thoughts associated with pain. Each item is rated on a 5-point Likert scale, from 0 ("not at all") to 4 ("all the time"). The total score ranges from 0 to 52, with higher scores indicating greater pain catastrophizing. The Italian version of the PCS has demonstrated excellent internal consistency (Cronbach's alpha = 0.92) and test-retest reliability (ICC = 0.842, p \< 0.001).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Psychological Flexibility
The Multidimensional Psychological Flexibility Inventory (MPFI-24) is a self-report measure assessing all flexibility and inflexibility processes within the Hexaflex/Inflexahex model. Respondents rate how well each item reflects their experience over the past two weeks using a 6-point Likert scale from 1 ("Never true") to 6 ("Always true"). The Italian version of the MPFI has demonstrated excellent internal consistency (Cronbach's alpha = 0.94) for both overall psychological flexibility and inflexibility, with subscale alphas ranging from 0.85 to 0.94.
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Self-Efficacy
The Pain Self-Efficacy Questionnaire (PSEQ) (10 items) is used in both clinical and research contexts to assess individuals' confidence in performing activities despite pain. Each item is rated on a 7-point Likert scale, from 0 ("not at all confident") to 6 ("completely confident"). Total scores range from 0 to 60, with higher scores indicating greater pain-related self-efficacy. The Italian version of the PSEQ has shown excellent internal consistency (Cronbach's alpha = 0.94) and good test-retest reliability (ICC = 0.82).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Coping
The Chronic Pain Coping Inventory (CPCI-42) (42 items) asks patients to rate how often they used behavioral and cognitive coping strategies during the previous week. The Italian version, validated across cultures, maintains its eight-subscale structure, with each subscale producing a score from 0 to 7. Higher scores reflect more frequent use of coping strategies. The Italian CPCI-42 has shown good internal consistency (Cronbach's alpha = 0.71-0.80) and reliability (ICC = 0.70-0.85, and \>0.85 for all subscales).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Anxiety
The Generalized Anxiety Disorder scale (GAD-7) (7 items) assesses symptoms of generalized anxiety. Respondents rate how often they have been bothered by each symptom over the past 14 days on a 4-point scale: 0 ("Not at all"), 1 ("Several days"), 2 ("More than half the days"), and 3 ("Nearly every day"). Total scores range from 0 to 21 and are interpreted as follows: 0-4 = minimal anxiety, 5-9 = mild anxiety, 10-14 = moderate anxiety, 15-21 = severe anxiety. The Italian version of the GAD-7 has shown good internal consistency (Cronbach's alpha = 0.918) and test-retest reliability (ICC = 0.83).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
Depression
The Patient Health Questionnaire (PHQ-9) is a self-report measure used to assess the severity of depressive symptoms. The nine items correspond to the DSM-IV criteria for major depressive disorder and evaluate symptom frequency over the past two weeks. Items include: little interest or pleasure in doing things, feeling down or hopeless, sleep issues, fatigue, appetite changes, feelings of worthlessness, difficulty concentrating, psychomotor changes, and suicidal thoughts. Each item is scored from 0 ("Not at all") to 3 ("Nearly every day"), with total scores ranging from 0 to 27. Interpretation: 0-4 = minimal depression, 5-9 = mild, 10-14 = moderate, 15-19 = moderately severe, and 20-27 = severe depression. The Italian version of the PHQ-9 has demonstrated good internal consistency (Cronbach's alpha = 0.918).
Time frame: T0 (baseline); T1 (7-weeks); T2 (6 months)
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