title: Chronic fatigue syndrome and fibromyalgia in diagnosed sleep disorders: a further test of the 'unitary' hypothesis.
abstract: BACKGROUND
  Since chronic fatigue syndrome (CFS) and fibromyalgia (FM) often co-exist, some believe they reflect the same process, somatization. Against that hypothesis are data suggesting FM but not CFS was common in patients with sleep-disordered breathing (SDB). The presence of discrete case definitions for CFS and FM allowed us to explore rates of CFS alone, CFS with FM, and FM alone in SDB patients compared to those with sleep complaints that fulfilled criteria for insomnia.
  
  
  METHODS
  Participants were 175 sequential patients with sleep-related symptoms (122 had SDB and 21 had insomnia) and 39 healthy controls. Diagnoses were made by questionnaires, tender point count, and rule out labs; sleepiness was assessed with Epworth Sleepiness Scale and mood with Beck Depression Inventory.
  
  
  RESULTS
  Rates of CFS, FM or CFS + FM were high: 13% in SDB and 48% in insomnia. CFS occurred frequently in SDB and insomnia, but FM occurred frequently only in insomnia. SDB patients with CFS and/or FM had higher daytime sleepiness than those without these disorders.
  
  
  CONCLUSIONS
  CFS patients should complete Epworth scales, and sleep evaluation should be considered for those with scores ≥ 16 before receiving the diagnosis of CFS; the coexistence of depressed mood in these patients suggests some may be helped by treatment of their depression. That FM was underrepresented in SDB suggests FM and CFS may have different underlying pathophysiological causes.
authors.affiliation: Department of Psychiatry, Sleep Research and Treatment Center, Penn State College of Medicine, Hershey, PA, 17033, USA. bobapejovic@gmail.com.
authors.forename: Slobodanka
authors.initials: S
authors.lastname: Pejovic
authors.affiliation: Department of Neurology, Pain and Fatigue Study Center, Mount Sinai Beth Israel, Icahn School of Medicine at Mount Sinai, New York, NY, 10003, USA. bnatelson@bethisraelny.org.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Natelson
authors.affiliation: Department of Psychiatry, School of Medicine, University of Crete, Iraklion, Greece. mbasta@med.uoc.gr.
authors.forename: Maria
authors.initials: M
authors.lastname: Basta
authors.affiliation: Department of Psychiatry, Sleep Research and Treatment Center, Penn State College of Medicine, Hershey, PA, 17033, USA. jfernandezmendoza@hmc.psu.edu.
authors.forename: Julio
authors.initials: J
authors.lastname: Fernandez-Mendoza
authors.affiliation: Department of Psychiatry, Sleep Research and Treatment Center, Penn State College of Medicine, Hershey, PA, 17033, USA. fmahr@hmc.psu.edu.
authors.forename: Fauzia
authors.initials: F
authors.lastname: Mahr
authors.affiliation: Department of Psychiatry, Sleep Research and Treatment Center, Penn State College of Medicine, Hershey, PA, 17033, USA. axv3@psu.edu.
authors.forename: Alexandros N
authors.initials: AN
authors.lastname: Vgontzas
mesh_terms: D000328:Adult; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology*; D015673:Fatigue Syndrome, Chronic / Q000453:epidemiology*; D005260:Female; D005356:Fibromyalgia / Q000453:epidemiology*; D006296:Health Services; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012890:Sleep; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D012894:Sleep Stages; D012893:Sleep Wake Disorders / Q000453:epidemiology; D011795:Surveys and Questionnaires