title: Higher frontal EEG synchronization in young women with major depression: a marker for increased homeostatic sleep pressure?
abstract: OBJECTIVE
  Major depressive disorder (MDD) is often associated with disturbances in circadian and/or sleep-wake dependent processes, which both regulate daytime energy and sleepiness levels.
  
  
  METHODS
  Analysis of continuous electroencephalographic (EEG) recordings during 40 h of extended wakefulness under constant routine conditions. Artifact-free EEG samples derived from 12 locations were subjected to spectral analysis. Additionally, half-hourly ratings of subjective tension and sleepiness levels and salivary melatonin measurements were collected.
  
  
  METHODS
  Centre for Chronobiology, Psychiatric Hospitals of the University of Basel, Switzerland.
  
  
  METHODS
  Eight young healthy women and 8 young untreated women with MDD.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  MDD women exhibited higher frontal low-frequency (FLA) EEG activity (0.5-5.0 Hz) during extended wakefulness than controls, particularly during the night. Enhanced FLA was paralleled by higher levels of subjective sleepiness and tension. In MDD women, overall FLA levels correlated positively with depression scores. The timing of melatonin onset did not significantly differ between the two groups, but the nocturnal secretion of salivary melatonin was significantly attenuated in MDD women.
  
  
  CONCLUSIONS
  Our data imply that young women with MDD live on a higher homeostatic sleep pressure level, as indexed by enhanced FLA during wakefulness. Its positive correlation with depression scores indicates a possible functional relationship. High FLA could reflect a use-dependent phenomenon in depression (enhanced cognitive rumination or tension) and/or an attenuated circadian arousal signal.
authors: Centre for Chronobiology, Psychiatric Hospitals of the University of Basel, Basel, Switzerland.
authors: Angelina
authors: A
authors: Birchler-Pedross
authors: Sylvia
authors: S
authors: Frey
authors: Sarah Laxhmi
authors: SL
authors: Chellappa
authors: Thomas
authors: T
authors: Götz
authors: Patrick
authors: P
authors: Brunner
authors: Vera
authors: V
authors: Knoblauch
authors: Anna
authors: A
authors: Wirz-Justice
authors: Christian
authors: C
authors: Cajochen
mesh_terms: D000328:Adult; D015415:Biomarkers; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000503:physiopathology*; D058407:Electroencephalography Phase Synchronization / Q000502:physiology*; D005260:Female; D006801:Humans; D008550:Melatonin / Q000032:analysis; D012463:Saliva / Q000737:chemistry; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D008550:Melatonin