title: The role of insomnia in the treatment of chronic fatigue.
abstract: BACKGROUND
  The definition of Chronic Fatigue Syndrome (CFS) overlaps with definitions of insomnia, but there is limited knowledge about the role of insomnia in the treatment of chronic fatigue.
  
  
  OBJECTIVE
  To test if improvement of insomnia during treatment of chronic fatigue was associated with improved outcomes on 1) fatigue and 2) cortisol recovery span during a standardized stress exposure.
  
  
  METHODS
  Patients (n = 122) with chronic fatigue received a 3.5-week inpatient return-to-work rehabilitation program based on Acceptance and Commitment Therapy, and had been on paid sick leave>8 weeks due their condition. A physician and a psychologist examined the patients, assessed medication use, and SCID-I diagnoses. Patients completed self-report questionnaires measuring fatigue, pain, depression, anxiety, and insomnia before and after treatment. A subgroup (n = 25) also completed the Trier Social Stress Test for Groups (TSST-G) before and after treatment. Seven cortisol samples were collected during each test and cortisol spans for the TSST-G were calculated.
  
  
  RESULTS
  A hierarchical regression analysis in nine steps showed that insomnia improvement predicted improvement in fatigue, independently of age, gender, improvement in pain intensity, depression and anxiety. A second hierarchical regression analysis showed that improvement in insomnia significantly predicted the cortisol recovery span after the TSST-G independently of improvement in fatigue.
  
  
  CONCLUSIONS
  Improvement in insomnia severity had a significant impact on both improvement in fatigue and the ability to recover from a stressful situation. Insomnia severity may be a maintaining factor in chronic fatigue and specifically targeting this in treatment could increase treatment response.
authors.affiliation: Norwegian University of Science and Technology, Department of Neuroscience, Trondheim, Norway; St. Olav's University Hospital, Department of Østmarka, Trondheim, Norway. Electronic address: havard.kallestad@ntnu.no.
authors.forename: Håvard
authors.initials: H
authors.lastname: Kallestad
authors.affiliation: St. Olav's University Hospital, Hysnes Rehabilitation Center, Trondheim, Norway; St. Olav's University Hospital, National Competence Center for Pain and Complex Disorders, Trondheim, Norway; Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, Trondheim, Norway.
authors.forename: Henrik B
authors.initials: HB
authors.lastname: Jacobsen
authors.affiliation: St. Olav's University Hospital, Hysnes Rehabilitation Center, Trondheim, Norway; Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, Trondheim, Norway; University of Oslo, Department of Psychology, Oslo, Norway.
authors.forename: Nils Inge
authors.initials: NI
authors.lastname: Landrø
authors.affiliation: St. Olav's University Hospital, Hysnes Rehabilitation Center, Trondheim, Norway; St. Olav's University Hospital, National Competence Center for Pain and Complex Disorders, Trondheim, Norway; Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, Trondheim, Norway.
authors.forename: Petter C
authors.initials: PC
authors.lastname: Borchgrevink
authors.affiliation: St. Olav's University Hospital, National Competence Center for Pain and Complex Disorders, Trondheim, Norway; University of Oslo, Department of Psychology, Oslo, Norway; Norwegian University of Science and Technology, Department of Psychology, Trondheim, Norway.
authors.forename: Tore C
authors.initials: TC
authors.lastname: Stiles
mesh_terms: D000328:Adult; D001007:Anxiety / Q000209:etiology; D015415:Biomarkers / Q000097:blood; D002908:Chronic Disease; D003863:Depression / Q000209:etiology; D005221:Fatigue / Q000097:blood / Q000209:etiology*; D015673:Fatigue Syndrome, Chronic / Q000097:blood / Q000150:complications / Q000209:etiology* / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009664:Norway; D012044:Regression Analysis; D062707:Return to Work; D057566:Self Report; D012720:Severity of Illness Index; D018582:Sick Leave; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood / Q000150:complications* / Q000175:diagnosis*; D013315:Stress, Psychological / Q000097:blood / Q000209:etiology; D009626:Terminology as Topic; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone
keywords: Cognitive therapy; Fatigue; Insomnia; Stress