title: Rethinking the duration requirement for generalized anxiety disorder: evidence from the National Comorbidity Survey Replication.
abstract: BACKGROUND
  The proposed revisions of the ICD and DSM diagnostic systems have led to increased interest in evaluation of diagnostic criteria. This report focuses on the DSM-IV requirement that episodes of generalized anxiety disorder (GAD) must persist for at least 6 months. Community epidemiological data are used to study the implications of changing this requirement in the range 1-12 months for estimates of prevalence, onset, course, impairment, co-morbidity, associations with parental GAD, and sociodemographic correlates.
  
  
  METHODS
  Data come from the US National Comorbidity Survey Replication (NCS-R), a US household survey carried out during 2001-2003. Version 3.0 of the WHO Composite International Diagnostic Interview (WMH-CIDI) was used to assess DSM-IV anxiety disorders, mood disorders, substance disorders, and impulse-control disorders.
  
  
  RESULTS
  Lifetime, 12-month, and 30-day prevalence estimates of DSM-IV GAD changed from 6.1%, 2.9%, and 1.8% to 4.2-12.7%, 2.2-5.5%, and 1.6-2.6% when the duration requirement was changed from 6 months to 1-12 months. Cases with episodes of 1-5 months did not differ greatly from those with episodes of > or = 6 months in onset, persistence, impairment, co-morbidity, parental GAD, or sociodemographic correlates.
  
  
  CONCLUSIONS
  A large number of people suffer from a GAD-like syndrome with episodes of < 6 months duration. Little basis for excluding these people from a diagnosis is found in the associations examined here.
authors.affiliation: Department of Health Care Policy, Harvard Medical School, Boston, MA 02115, USA. kessler@hcp.med.harvard.edu
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Kessler
authors.forename: Nancy
authors.initials: N
authors.lastname: Brandenburg
authors.forename: Michael
authors.initials: M
authors.lastname: Lane
authors.forename: Peter
authors.initials: P
authors.lastname: Roy-Byrne
authors.forename: Paul D
authors.initials: PD
authors.lastname: Stang
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Wittchen
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D016021:Epidemiologic Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors