title: Age at migration and future risk of psychotic disorders among immigrants in the Netherlands: a 7-year incidence study.
abstract: OBJECTIVE
  The purpose of this study was to examine whether the increased risk for developing a psychotic disorder among immigrants is related to their age at the time of migration.
  
  
  METHODS
  In a 7-year first-contact incidence study, immigrants to the Netherlands and Dutch citizens, ages 15-54 years, who made a first contact with a physician for a suspected psychotic disorder were identified. Diagnostic interviews were administered, and DSM-IV diagnoses were determined by consensus between two psychiatrists. A comprehensive municipal registration system provided the denominator, including information on ethnicity and age at the time of migration.
  
  
  RESULTS
  Lower age at the time of migration was associated with a higher incidence of psychotic disorders among immigrants. People who migrated between the ages of 0 and 4 years had the most elevated risk for psychotic disorders compared with the risk among Dutch citizens (age- and sex-adjusted incidence rate ratio=2.96, 95% confidence interval [CI]=2.10-4.17), and the risk gradually decreased with older age at migration (adjusted incidence rate ratio for migration at 5-9 years, 10-14 years, and >29 years, respectively: 2.31 [CI=1.61-3.29], 1.51 [CI=1.02-2.25], and 1.00 [CI=0.58-1.72]).
  
  
  CONCLUSIONS
  The adverse influence of migration on the risk for psychotic disorders is most prominent in early life, suggesting that this is an important period in the etiology of the illness.
authors.affiliation: Parnassia Psychiatric Institute, The Hague, Maastricht, the Netherlands. w.veling@parnassia.nl
authors.forename: Wim
authors.initials: W
authors.lastname: Veling
authors.forename: Hans W
authors.initials: HW
authors.lastname: Hoek
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Selten
authors.forename: Ezra
authors.initials: E
authors.lastname: Susser
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015331:Cohort Studies; D054242:Emigrants and Immigrants / Q000523:psychology / Q000706:statistics & numerical data*; D004641:Emigration and Immigration; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors