title: Temporal coherence in ultradian sleep EEG rhythms in a never-depressed, high-risk cohort of female adolescents.
abstract: BACKGROUND
  Previous work has indicated that low temporal coherence of ultradian sleep electroencephalographic rhythms is characteristic of depressed patients and of depressed women, in particular. It may also be evident in one quarter of those at high risk, based on a family history of depression.
  
  
  METHODS
  The present study evaluated temporal coherence of sleep electroencephalographic rhythms in 41 adolescent girls with a maternal history of depression (high risk) and 40 healthy controls (low risk). The entire sample was followed clinically every 6 months for 2 years.
  
  
  RESULTS
  Temporal coherence was significantly lower among the high-risk girls than in controls. Regression analyses predicted group from coherence values and correctly classified 70% of the high-risk group with a false-positive rate of 5% among controls. Moreover, 54% of the high-risk girls were identified with extreme low coherence. On clinical follow up, 14 girls showed depressive symptoms, 9 in the high-risk group (22.5%) and 5 controls (12.2%). Six met DSM-IV criteria for first-episode major depressive disorder, five high-risk and one control. Most importantly, 41% of those identified as having the most abnormal coherence values either showed symptoms of depression or met diagnostic criteria upon follow up.
  
  
  CONCLUSIONS
  Low temporal coherence is evident in adolescent girls at high risk for depression. The more abnormal the coherence, the greater the risk of a first episode of major depressive disorder within 2 years of sleep study, approximately 10 times greater than in controls.
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Morehouse
authors.forename: Vivek
authors.initials: V
authors.lastname: Kusumakar
authors.forename: Stanley P
authors.initials: SP
authors.lastname: Kutcher
authors.forename: John
authors.initials: J
authors.lastname: LeBlanc
authors.forename: Roseanne
authors.initials: R
authors.lastname: Armitage
mesh_terms: D000204:Activity Cycles / Q000502:physiology*; D000293:Adolescent; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D015331:Cohort Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D011569:Psychiatric Status Rating Scales; D012306:Risk; D012894:Sleep Stages / Q000502:physiology*