title: Family history of psychiatric disorders and age at first contact in schizophrenia: an epidemiological study.
abstract: BACKGROUND
  The risk for schizophrenia has been associated with a family history of this and other psychiatric disorders. The relationship between age at first contact and family history of psychiatric illness is not certain.
  
  
  OBJECTIVE
  To estimate the risks for schizophrenia associated with a range of psychiatric diagnoses in family members and to investigate the relationship between these risks and age at first contact for schizophrenia.
  
  
  METHODS
  A nested case-control study design was employed. Psychiatric admission data and socio-economic data were available for 7704 cases admitted between 1981 and 1998 in Denmark, 192,590 gender- and age-matched controls, and for the parents and siblings of all subjects.
  
  
  RESULTS
  Controlling for socio-economic factors, risk for schizophrenia was associated with a family history of all psychiatric disorders except substance misuse and independently with a family history of suicide. The risk for schizophrenia associated with a family history of psychiatric disorders decreased as age at first contact increased.
  
  
  CONCLUSIONS
  Risk for schizophrenia is associated with a range of psychiatric disorders in family members and these risks are not constant across the risk period.
authors.affiliation: National Centre for Register-Based Research, Aarhus University, Taasingegade 1, Aarhus 8000 C, Denmark. mb@ncrr.dk
authors.forename: Majella
authors.initials: M
authors.lastname: Byrne
authors.forename: Esben
authors.initials: E
authors.lastname: Agerbo
authors.forename: Preben Bo
authors.initials: PB
authors.lastname: Mortensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000235:genetics*; D009679:Nuclear Family; D010290:Parents; D012044:Regression Analysis; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology / Q000235:genetics; D012737:Sex Factors