Chronic pain is a serious concern that disproportionately affects Veterans compared to the general public; Veterans are diagnosed with CP at particularly high rates (47 - 56%) with a 40% greater rate of severe pain than non-Veterans. Veterans with chronic pain face numerous negative functional outcomes, including decreased ability to complete daily work activities, less social support from and closeness with family members, increased chronic health conditions (e.g., cancer, heart disease), and higher mortality compared to Veterans without chronic pain. Unfortunately, the use of medication for long-term pain treatment, though often utilized, has both limited efficacy and potentially harmful outcomes. Given these concerns, there is an urgent need for innovative and integrative approaches for non-medical pain self-management management. Despite the critical importance of effective pain self-management programs, many Veterans with chronic pain do not engage in pain self-management programs available through the VA. There are numerous reasons for this, including perceived time and transportation concerns and pain-related barriers to attending in-person care options. To improve Veterans' quality of life and it is important to develop and evaluate innovative, accessible, evidence-based interventions for managing pain that can be easily accessed where healthcare happens most - within the home.

One approach with over twenty years of efficacious treatment for chronic pain is Acceptance and Commitment Therapy for Chronic Pain (ACT-CP). ACT is a well-established and VA-approved approach to chronic pain management, and focuses on committing to behavior change that reflects personal values, leading to significant improvement in life functioning. Though provided at many VA hospitals, clinician-delivered ACT for chronic pain has not had a nationwide rollout and is not available at all VA pain clinics. Additionally, many Veterans with chronic pain do not access one-on-one therapeutic treatment due to transportation and time issues. Thankfully, for adults with chronic pain outside of the VA, technology-delivered ACT has been found to be acceptable, useful, and efficacious in delivering pain treatment. However, although research suggests it could help with at-home pain management, no ACT for chronic pain online treatment exists specifically for Veterans and their particular care needs.

To address this treatment option gap, the research team created an online Veteran ACT for chronic pain (VACT-CP) during the PI's Rehabilitation R\&D CDA-2 project. VACT-CP is guided by an interactive virtual coach (Coach Anne) to help address pain-related distress and functional difficulties of chronic pain (e.g., avoidance, reactivity) over seven weeks of treatment. Preliminary findings suggest that VACT-CP is highly usable, perceived as helpful, and can help Veterans increase their pain acceptance and pain management. The primary outcomes for this project will be to complete a three-site, fully-powered efficacy trial comparing VACT-CP to an active online control condition (total n = 200) to investigate whether VACT-CP can improve pain-related functioning and quality of life. In addition, the investigators will analyze data from the VACT-CP group to assess whether the hypothesized mechanism of change (psychological flexibility) mediates the impact of pain severity on pain-related functioning.