Background: Chronic pain (CP) is a leading cause of disability worldwide and is associated with substantial psychological, functional, and social burden. Acceptance and Commitment Therapy (ACT) has demonstrated efficacy in improving pain acceptance and functioning; however, access to psychological care remains limited. Internet-based interventions (IBIs) may help bridge this gap. To date, no ACT internet-based intervention has been developed and tested for individuals with CP in Italy. The present pilot randomized controlled trial (RCT) evaluated feasibility, acceptability, usability, and exploratory changes in pain acceptance of MobACT, a guided internet-based ACT intervention translated and adapted for the Italian context.

Methods: A two-arm pilot RCT with parallel groups (1:1 allocation) was conducted. Forty adults with CP were randomized to either the MobACT intervention (n = 20) or a waitlist control group (n = 20). The seven-week guided intervention was delivered via the Iterapi platform. Feasibility outcomes included recruitment, retention, usability, satisfaction, intervention experience, and participant feedback. The primary exploratory clinical outcome was pain acceptance, measured using the Chronic Pain Acceptance Questionnaire (CPAQ-20) at baseline (T0) and post-intervention (T1). Feasibility, usability, and participant experiences were explored through post-intervention questionnaires and semi-structured interviews analyzed using thematic analysis.

Results: Pain acceptance significantly improved over time across participants (p < .001), but the time × group interaction was not significant (p = .978), indicating no evidence of a differential change between MobACT and waitlist during the pilot period. Reliability of the CPAQ-20 was good at both time points (α = 0.802–0.842). Qualitative findings indicated high usability, satisfaction, and perceived applicability of ACT strategies. Participants reported increased awareness, reduced rumination, improved emotional regulation, and greater engagement in valued activities, despite limited changes in pain intensity.

Conclusions: Findings support the feasibility, acceptability, and usability of MobACT as a culturally adapted internet-based ACT intervention for CP in Italy. Exploratory outcome findings should not be interpreted as evidence of efficacy; rather, they support further evaluation in a larger, fully powered RCT with more comprehensive engagement monitoring and longer follow-up.