title: The PsyCoLaus study: methodology and characteristics of the sample of a population-based survey on psychiatric disorders and their association with genetic and cardiovascular risk factors.
abstract: BACKGROUND
  The Psychiatric arm of the population-based CoLaus study (PsyCoLaus) is designed to: 1) establish the prevalence of threshold and subthreshold psychiatric syndromes in the 35 to 66 year-old population of the city of Lausanne (Switzerland); 2) test the validity of postulated definitions for subthreshold mood and anxiety syndromes; 3) determine the associations between psychiatric disorders, personality traits and cardiovascular diseases (CVD), 4) identify genetic variants that can modify the risk for psychiatric disorders and determine whether genetic risk factors are shared between psychiatric disorders and CVD. This paper presents the method as well as sociodemographic and somatic characteristics of the sample.
  
  
  METHODS
  All 35 to 66 year-old persons previously selected for the population-based CoLaus survey on risk factors for CVD were asked to participate in a substudy assessing psychiatric conditions. This investigation included the Diagnostic Interview for Genetic Studies to elicit diagnostic criteria for threshold disorders according to DSM-IV and algorithmically defined subthreshold syndromes. Complementary information was collected on potential risk and protective factors for psychiatric disorders, migraine and on the morbidity of first-degree relatives, whereas the collection of DNA and plasma samples was already part of the original CoLaus survey.
  
  
  RESULTS
  A total of 3,691 individuals completed the psychiatric evaluation (67% participation). The gender distribution of the sample did not differ significantly from that of the general population in the same age range. Although the youngest 5-year band of the cohort was underrepresented and the oldest 5-year band overrepresented, participants of PsyCoLaus and individuals who refused to participate revealed comparable scores on the General Health Questionnaire, a self-rating instrument completed at the somatic exam.
  
  
  CONCLUSIONS
  Despite limitations resulting from the relatively low participation in the context of a comprehensive and time-consuming investigation, the PsyCoLaus study should significantly contribute to the current understanding of psychiatric disorders and comorbid somatic conditions by: 1) establishing the clinical relevance of specific psychiatric syndromes below the DSM-IV threshold; 2) determining comorbidity between risk factors for CVD and psychiatric disorders; 3) assessing genetic variants associated with common psychiatric disorders and 4) identifying DNA markers shared between CVD and psychiatric disorders.
authors.affiliation: Department of Psychiatry, CHUV, Lausanne, Switzerland. martin.preisig@chuv.ch
authors.forename: Martin
authors.initials: M
authors.lastname: Preisig
authors.forename: Gérard
authors.initials: G
authors.lastname: Waeber
authors.forename: Peter
authors.initials: P
authors.lastname: Vollenweider
authors.forename: Pascal
authors.initials: P
authors.lastname: Bovet
authors.forename: Stéphane
authors.initials: S
authors.lastname: Rothen
authors.forename: Caroline
authors.initials: C
authors.lastname: Vandeleur
authors.forename: Patrice
authors.initials: P
authors.lastname: Guex
authors.forename: Lefkos
authors.initials: L
authors.lastname: Middleton
authors.forename: Dawn
authors.initials: D
authors.lastname: Waterworth
authors.forename: Vincent
authors.initials: V
authors.lastname: Mooser
authors.forename: Federica
authors.initials: F
authors.lastname: Tozzi
authors.forename: Pierandrea
authors.initials: P
authors.lastname: Muglia
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005192:Family Health; D005240:Feasibility Studies; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D008875:Middle Aged; D010551:Personality; D011159:Population Surveillance / Q000379:methods*; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology
chemical_list: D015415:Biomarkers