title: Intraindividual variability in daily sleep and pain ratings among chronic pain patients: bidirectional association and the role of negative mood.
abstract: OBJECTIVE
  Sleep disturbance is a common problem among chronic pain patients. Cross-sectional data from clinical populations and experimental studies have shown an association between sleep disturbance and pain. However, there has been little prospective research into the relationship between daily variability between sleep and pain among chronic pain patients.
  
  
  METHODS
  Twenty-two women with chronic pain (back pain, facial pain, fibromyalgia) completed a sleep diary and wore an actigraph for a 2-week period. Self-report measures of pain, mood, and sleep were also completed at baseline. Hierarchical linear modeling (HLM) was used to examine intraindividual variability in sleep and pain ratings among these women. The impact of mood and baseline pain ratings was also examined as potential moderators.
  
  
  RESULTS
  Hierarchical linear modeling analyses supported a bidirectional relationship between sleep and pain, such that a night of poor sleep was followed by increased pain ratings the following day and a day of increased pain was followed by a night of poor sleep. Depression scores further influenced these relationships.
  
  
  CONCLUSIONS
  Prospective examination supported a bidirectional relationship between sleep and pain among a group of women with chronic pain. Depressive symptoms had a moderating impact on these relationships. These findings suggest that addressing sleep is important in the treatment of individuals with chronic pain.
authors.affiliation: Department of Psychiatry and Human Behavior, Brown University Medical School, Providence, RI, USA. eobrien4@Lifespan.org
authors.forename: Erin M
authors.initials: EM
authors.lastname: O'Brien
authors.forename: Lori B
authors.initials: LB
authors.lastname: Waxenberg
authors.forename: James W
authors.initials: JW
authors.lastname: Atchison
authors.forename: Henry A
authors.initials: HA
authors.lastname: Gremillion
authors.forename: Roland M
authors.initials: RM
authors.lastname: Staud
authors.forename: Christina S
authors.initials: CS
authors.lastname: McCrae
authors.forename: Michael E
authors.initials: ME
authors.lastname: Robinson
mesh_terms: D056044:Actigraphy; D000328:Adult; D000339:Affect; D002908:Chronic Disease; D002940:Circadian Rhythm; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008954:Models, Biological; D010146:Pain / Q000150:complications / Q000503:physiopathology*; D010147:Pain Measurement; D012680:Sensitivity and Specificity; D012890:Sleep; D012893:Sleep Wake Disorders / Q000150:complications / Q000503:physiopathology*; D013223:Statistics as Topic