title: Changes in Sleep Problems and Psychological Flexibility following Interdisciplinary Acceptance and Commitment Therapy for Chronic Pain: An Observational Cohort Study.
abstract: OBJECTIVE
  Cognitive and behavioral treatments (CBT) for sleep problems and chronic pain have shown good results, although these results could improve. More recent developments based on the psychological flexibility model, the model underlying Acceptance and Commitment Therapy (ACT) may offer a useful addition to traditional CBT. The aim of this study was to examine whether an ACT-based treatment for chronic pain is associated with improved sleep. Secondly, we examined the associations between changes on measures of psychological flexibility and sleep-related outcomes.
  
  
  METHODS
  The study used an observational cohort methodology. Participants were 252 patients (73.8% female) attending a 4-week, interdisciplinary, pain management program in London, United Kingdom. Participants completed standard self-report measures of pain and functioning, sleep outcomes, and processes of psychological flexibility. Pre- to post-treatment, and pre-treatment to follow-up measures were examined for statistically significant differences using paired samples t-tests. Secondarily, hierarchical multiple regression analyses were conducted to examine change in process measures in relation to change in treatment outcome.
  
  
  RESULTS
  Participants showed statistically significant improvements (all p < 0.001) at post-treatment on measures of insomnia severity (d = 0.45), sleep interference (d = 0.61), and sleep efficiency (d = 0.32). Significant improvements in insomnia severity and sleep interference were also observed at 9-month follow up. Small to medium effect sizes were observed across the sleep outcomes. Statistically significant changes were also observed on measures of psychological flexibility, and these improvements were significantly associated with improvements on sleep-related outcomes, independently contributing up to 19% of unique variance.
  
  
  CONCLUSIONS
  This study supports the potential usefulness of ACT-based treatments for chronic pain for addressing co-occurring sleep difficulties. Further research is needed to determine how to improve the impact of this treatment for co-morbid pain and sleep difficulties, possibly using a randomized-controlled trial design.
authors.affiliation: INPUT Pain Management, Guys and St. Thomas NHS Foundation Trust Hospitals London, UK.
authors.forename: Aisling
authors.initials: A
authors.lastname: Daly-Eichenhardt
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London London, UK.
authors.forename: Whitney
authors.initials: W
authors.lastname: Scott
authors.affiliation: INPUT Pain Management, Guys and St. Thomas NHS Foundation Trust Hospitals London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Howard-Jones
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London London, UK.
authors.forename: Thaleia
authors.initials: T
authors.lastname: Nicolaou
authors.affiliation: INPUT Pain Management, Guys and St. Thomas NHS Foundation Trust HospitalsLondon, UK; Department of Psychology, Institute of Psychiatry, Psychology, and Neuroscience, King's College LondonLondon, UK.
authors.forename: Lance M
authors.initials: LM
authors.lastname: McCracken
keywords: acceptance and commitment therapy; chronic pain; insomnia