title: Decreased nocturnal growth hormone secretion and sleep fragmentation in combat-related posttraumatic stress disorder; potential predictors of impaired memory consolidation.
abstract: BACKGROUND
  Healthy sleep facilitates the consolidation of newly acquired memories. Although patients with posttraumatic stress disorder (PTSD) often complain of sleep disturbances and memory deficits, the interrelatedness of these symptoms is not well understood. Sleep may be disturbed in PTSD by increased awakenings during sleep, which has been associated with decreased growth hormone (GH) secretion. We conducted a controlled study in which we assessed sleep fragmentation, nocturnal secretion of GH, and memory consolidation in patients with PTSD.
  
  
  METHODS
  While sleep EEG was being monitored, 13 veterans with PTSD, 15 trauma controls (TC) and 15 healthy controls (HC) slept with an iv catheter, through which blood was collected every 20 min from 23:00 h to 08:00 h. Declarative memory encoding was assessed with the 15 word task before sleep, and consolidation was assessed the next morning by a free recall.
  
  
  RESULTS
  Sleep was more fragmented in patients with PTSD, with more awakenings in the first half of the night (p<0.05). Plasma levels of GH during the night were significantly decreased in PTSD compared with HC (p<0.05). Furthermore, GH secretion and awakenings were independent predictors for delayed recall, which was lower in PTSD compared to HC (p<0.05).
  
  
  CONCLUSIONS
  These data show that PTSD is associated with increased awakenings during sleep and decreased nocturnal GH secretion. Furthermore, decreased GH secretion may be related to sleep fragmentation and both variables may exert a negative effect on sleep dependent memory consolidation.
authors.affiliation: Research Centre Military Mental Healthcare, Utrecht, The Netherlands. S.vanliempt@umcutrecht.nl
authors.forename: Saskia
authors.initials: S
authors.lastname: van Liempt
authors.forename: Eric
authors.initials: E
authors.lastname: Vermetten
authors.forename: Eef
authors.initials: E
authors.lastname: Lentjes
authors.forename: Johan
authors.initials: J
authors.lastname: Arends
authors.forename: Herman
authors.initials: H
authors.lastname: Westenberg
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology; D003130:Combat Disorders / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D015536:Down-Regulation; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D012153:Retention, Psychology / Q000502:physiology; D012307:Risk Factors; D012892:Sleep Deprivation / Q000209:etiology* / Q000378:metabolism; D013313:Stress Disorders, Post-Traumatic / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D014728:Veterans
chemical_list: D019382:Human Growth Hormone