Insomnia symptoms and chronic pain: Outcomes of an interdisciplinary pain rehabilitation program.

OBJECTIVES Insomnia is a highly prevalent problem among patients with chronic pain. Interdisciplinary pain rehabilitation programs (IPRPs) are a leading treatment option for chronic pain; however, research is limited and existing findings are mixed on the impact of insomnia symptoms on IPRP outcomes and the extent to which insomnia symptoms improve as a result of IPRP treatment. METHODS In this study, insomnia and pain-related outcomes following a 10-week IPRP were examined from a relatively large sample (N = 393) of adult patients with varying chronic pain conditions who completed the Insomnia Severity Index (ISI) at program admission and discharge. Both group- and individual-level changes in insomnia severity were examined to evaluate statistically and clinically significant changes in insomnia symptoms, along with the impact of insomnia symptoms on measures of pain, emotional distress, and functioning. Participants were categorized as having no clinically significant insomnia symptoms (NCSI), mild, moderate, or severe insomnia based on ISI scores. RESULTS Higher levels of insomnia severity were associated with worse pain, functioning, and emotional distress. Most patients reporting mild, moderate, or severe insomnia symptoms at program admission moved to a lower insomnia symptom category at the time of discharge (62%); however, only 33% of these patients reported a meaningful score reduction (i.e., ISI change ≥8 points). In addition, insomnia symptoms had a negative impact on treatment gains related to pain interference and physical health-related quality of life. DISCUSSION These findings suggest that usual IPRP care confers overall treatment benefit for individuals with chronic pain and insomnia. However, insomnia symptoms may negatively impact pain treatment outcomes and usual care appears insufficient to address elevated insomnia symptoms for many patients. Additional insomnia-specific treatment may be warranted for patients with comorbid chronic pain.