title: REM sleep latency and wakefulness in the first sleep cycle as markers of major depression: a controlled study vs. schizophrenia and normal controls.
abstract: BACKGROUND
  REM sleep latency is a clinically significant sleep variable that is found to be decreased in several psychiatric disorders. However, it is not known whether alteration of REM sleep latency is similar across disorders. In order to test whether incorporation of wakefulness in the first sleep cycle has a different outcome on REM sleep latency in different clinical groups, the authors have investigated correlation between sleep variables in the first sleep cycle in 25 patients with major depression, 24 patients with chronic schizophrenia, and in 10 healthy subjects.
  
  
  RESULTS
  REM sleep latency correlates with the duration of wakefulness in the first cycle in patients suffering from chronic schizophrenia and in healthy subjects. This correlation does not hold true in patients suffering from major depression.
  
  
  CONCLUSIONS
  Wakefulness incorporated in the first cycle influences REM sleep latency in healthy subjects and in patients suffering from chronic schizophrenia but not in patients suffering from major depression. This finding further supports the evidence that reduced REM sleep latency is a nonflexible marker of depression.
authors.affiliation: Abarbanel Mental Health Center, Bat Yam, Israel. vadir@post.tau.ac.il
authors.forename: Vadim S
authors.initials: VS
authors.lastname: Rotenberg
authors.forename: Eyal
authors.initials: E
authors.lastname: Shami
authors.forename: Yoram
authors.initials: Y
authors.lastname: Barak
authors.forename: Peter
authors.initials: P
authors.lastname: Indursky
authors.forename: Leonid
authors.initials: L
authors.lastname: Kayumov
authors.forename: Mordechai
authors.initials: M
authors.lastname: Mark
mesh_terms: D000328:Adult; D002908:Chronic Disease; D003865:Major Depressive Disorder / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011569:Psychiatric Status Rating Scales; D012565:Schizophrenic Psychology; D012894:Sleep Stages; D012895:Sleep, REM; D014851:Wakefulness