BackgroundInterdisciplinary pain rehabilitation programs are an evidence‐based biopsychosocial treatment approach for chronic pain. The purpose of the current study is to assess outcomes for a 10‐week interdisciplinary, acceptance and commitment therapy (ACT)‐based, outpatient treatment model and to evaluate the relationship between psychological process variables (ie, pain catastrophizing, pain acceptance, pain self‐efficacy) and treatment outcomes.Methods137 adults with chronic pain completed an interdisciplinary pain rehabilitation program. Measures of pain, pain interference, health‐related quality of life, anxiety, depressed mood, insomnia, pain catastrophizing, pain acceptance, and pain self‐efficacy were completed at admission and discharge. Data were also collected on demographic and clinical variables, including opioid use.ResultsResults indicated significant changes in all measures at program discharge compared to admission. Opioid doses were also reduced. Results of within‐subjects meditational analyses indicated that pain catastrophizing accounted for a significant portion of the treatment effect for pain severity, pain interference, and depressed mood. Pain acceptance was a mediator for change in depressed mood, whereas pain self‐efficacy was a mediator for pain interference outcomes.ConclusionsThis study supports a 10‐week, ACT‐based treatment model for interdisciplinary chronic pain rehabilitation. In addition, pain catastrophizing, pain acceptance, and pain self‐efficacy were each found to be mechanisms by which individuals achieve successful treatment outcomes. This research provides further support for interdisciplinary rehabilitation approaches for chronic pain.

Findings from the current study indicate a pattern of results similar to prior studies in which greater levels of catastrophic thinking is associated with higher perceived pain intensity whereas greater levels of acceptance relate to better functioning in activities despite chronic pain. However, in the current study, both acceptance and catastrophizing were associated with negative affect. These relationships were significant beyond the effects of clinical and demographic variables. These results support the role of pain acceptance as an important contribution to chronic pain-related outcomes alongside the well-established role of pain catastrophizing. Results are limited by reliance on self-report data, cross-sectional design, and low racial/ethnic diversity.