title: Izmir mental health survey for gene-environment interaction in psychoses (TürkSch): objectives and methodology.
abstract: OBJECTIVE
  To describe the objectives and design of a multistage study on the prevalence and risk factors of mental health problems, in particular psychotic disorders and psychotic symptoms, by assessing a probabilistic sample of household residents in the Izmir Metropolitan Area, aged 15-64 years.
  
  
  METHODS
  The study included three different observation frames. In the first stage, of which methodology is in the focus of this paper, the primary screening instrument was the Composite International Diagnostic Interview 2.1, which assesses lifetime and/or last one year occurrence of several DSM-IV disorders. Second, a parallel survey of social capital of administrative wards was conducted in the same neighbourhoods. Third, a nested-case control study was performed to study effects of genetic and environmental risk factors on wide psychosis phenotype.
  
  
  RESULTS
  A total of 4011 males and females were contacted through a multistage clustered area probability sample of administrative neighbourhoods and households, covering 9 districts and 302 neighbourhoods. The response rate for the first stage was 76.5% in 5242 eligible households. Respondents were interviewed at home in 2008 for the screening of included mental health problems. The screened disorders were mood disorders (last 1 year), schizophrenia and other non-affective psychotic disorders (lifetime), and dependence and abuse of psychoactive substances (lifetime).
  
  
  CONCLUSIONS
  Although cross-sectional in nature, the TürkSch has a unique study design and yields data of high quality. This enables study of the prevalence, risk and higher-order interactions underlying ill-health in the Turkish population, with a specific focus on psychosis.
authors.affiliation: Atatürk Public Hospital, Departmen of Psychiatry, Sinop, Turkey. tolgabinbay@yahoo.com
authors.forename: Tolga
authors.initials: T
authors.lastname: Binbay
authors.forename: Hayriye
authors.initials: H
authors.lastname: Elbi
authors.forename: Köksal
authors.initials: K
authors.lastname: Alptekin
authors.forename: Feride
authors.initials: F
authors.lastname: Aksu Tanık
authors.forename: Marjan
authors.initials: M
authors.lastname: Drukker
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Onay
authors.forename: Ferda
authors.initials: F
authors.lastname: Özkınay
authors.forename: Nesli
authors.initials: N
authors.lastname: Zağlı
authors.forename: Jim
authors.initials: J
authors.lastname: Van Os
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D059647:Gene-Environment Interaction; D006306:Health Surveys / Q000379:methods*; D006801:Humans; D008297:Male; D008603:Mental Health / Q000706:statistics & numerical data*; D008875:Middle Aged; D015995:Prevalence; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D012307:Risk Factors; D014421:Turkey / Q000453:epidemiology; D055815:Young Adult