title: The 2-week duration criterion and severity and course of early childhood depression: implications for nosology.
abstract: BACKGROUND
  Although validity for DSM-IV MDD symptom criteria in preschoolers has been demonstrated, whether the 2-week duration criterion is an appropriate threshold of clinical significance at this age remains unclear. The current study aimed to begin addressing this question.
  
  
  METHODS
  Three hundred and six preschoolers were recruited from community sites and followed longitudinally for 2 years. A subsample including healthy preschoolers (N=77) and those with MDD (N=74) were examined. The MDD group was further divided based upon meeting (DSM, N=24) or failing to meet (<DSM, N=50) the DSM-IV 2-week duration criterion. Groups were compared on parent and teacher report measures of symptom severity and functional impairment at baseline and 2-year follow-up.
  
  
  CONCLUSIONS
  A larger sample of depressed preschoolers and refined measures of duration are needed to replicate the current study.
  
  
  RESULTS
  Preschoolers with MDD differed significantly from controls on the majority of measures examined regardless of duration status and time of assessment. Further, the DSM group significantly differed from the<DSM group at baseline on measures of MDD symptom severity and impairment. No differences in the risk of a MDD diagnosis at follow-up were found on the basis of duration group status.
  
  
  CONCLUSIONS
  DSM-IV duration criterion failed to capture all clinically affected preschoolers at baseline or confer greater predictive validity for a depression diagnosis 2 years later. Findings suggest that preschoolers meeting all DSM-IV MDD criteria except for episode duration exhibit a clinically significant form of depression and experience a 2-year MDD outcome similar to those meeting full criterion.
authors.affiliation: Washington University School of Medicine, Department of Psychiatry, Saint Louis, Missouri 63110, USA. gaffreym@wustl.edu
authors.forename: Michael S
authors.initials: MS
authors.lastname: Gaffrey
authors.forename: Andy C
authors.initials: AC
authors.lastname: Belden
authors.forename: Joan L
authors.initials: JL
authors.lastname: Luby
mesh_terms: D002675:Child, Preschool; D003863:Depression; D003866:Depressive Disorder / Q000175:diagnosis; D003865:Major Depressive Disorder / Q000175:diagnosis*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013997:Time Factors