title: Lifetime co-morbidity of DSM-IV disorders in the US National Comorbidity Survey Replication Adolescent Supplement (NCS-A).
abstract: BACKGROUND
  Research on the structure of co-morbidity among common mental disorders has largely focused on current prevalence rather than on the development of co-morbidity. This report presents preliminary results of the latter type of analysis based on the US National Comorbidity Survey Replication Adolescent Supplement (NCS-A).
  
  
  METHODS
  A national survey was carried out of adolescent mental disorders. DSM-IV diagnoses were based on the Composite International Diagnostic Interview (CIDI) administered to adolescents and questionnaires self-administered to parents. Factor analysis examined co-morbidity among 15 lifetime DSM-IV disorders. Discrete-time survival analysis was used to predict first onset of each disorder from information about prior history of the other 14 disorders.
  
  
  RESULTS
  Factor analysis found four factors representing fear, distress, behavior and substance disorders. Associations of temporally primary disorders with the subsequent onset of other disorders, dated using retrospective age-of-onset (AOO) reports, were almost entirely positive. Within-class associations (e.g. distress disorders predicting subsequent onset of other distress disorders) were more consistently significant (63.2%) than between-class associations (33.0%). Strength of associations decreased as co-morbidity among disorders increased. The percentage of lifetime disorders explained (in a predictive rather than a causal sense) by temporally prior disorders was in the range 3.7-6.9% for earliest-onset disorders [specific phobia and attention deficit hyperactivity disorder (ADHD)] and much higher (23.1-64.3%) for later-onset disorders. Fear disorders were the strongest predictors of most other subsequent disorders.
  
  
  CONCLUSIONS
  Adolescent mental disorders are highly co-morbid. The strong associations of temporally primary fear disorders with many other later-onset disorders suggest that fear disorders might be promising targets for early interventions.
authors.affiliation: Department of Health Care Policy, Harvard Medical School, Boston, MA 02115, USA. ncs@hcp.med.harvard.edu
authors.forename: R C
authors.initials: RC
authors.lastname: Kessler
authors.forename: S
authors.initials: S
authors.lastname: Avenevoli
authors.forename: K A
authors.initials: KA
authors.lastname: McLaughlin
authors.forename: J Greif
authors.initials: JG
authors.lastname: Green
authors.forename: M D
authors.initials: MD
authors.lastname: Lakoma
authors.forename: M
authors.initials: M
authors.lastname: Petukhova
authors.forename: D S
authors.initials: DS
authors.lastname: Pine
authors.forename: N A
authors.initials: NA
authors.lastname: Sampson
authors.forename: A M
authors.initials: AM
authors.lastname: Zaslavsky
authors.forename: K Ries
authors.initials: KR
authors.lastname: Merikangas
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002653:Child Behavior Disorders / Q000453:epidemiology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology