title: Schizophrenia risk factors constitute general risk factors for psychiatric symptoms in the population.
abstract: BACKGROUND
  The presence of a psychosis continuum is suggested by studies showing that schizophrenia and non-clinical psychotic symptoms in the general population share the same risk factors. However, to our knowledge no large-scale studies have been conducted which examine the specificity of these risk factors in the general population.
  
  
  OBJECTIVE
  To investigate whether socio-demographic characteristics associated with non-clinical psychotic symptoms are also associated with other psychiatric symptoms. And secondly, to examine to what extent concomitant psychiatric symptoms explain the relationship between socio-demographic characteristics and non-clinical psychotic symptoms.
  
  
  METHODS
  In a general population sample of 4894 subjects (mean age 39 years, 45% men) from the Utrecht Health Project we investigated the associations of socio-demographical characteristics with non-clinical psychotic symptoms and other psychiatric symptoms by using the SCL-90. We examined these associations using multivariable logistic regression analyses with and without controlling for the presence of other psychiatric symptoms.
  
  
  RESULTS
  Participants with non-clinical psychotic symptoms had an 89% probability of concomitant depressive, anxiety or phobic anxiety symptoms, compared to 11% in participants without psychotic symptoms. The risk profiles for non-clinical psychotic symptoms and other psychiatric symptoms were largely similar. Non-Dutch ethnicity was most strongly associated with non-clinical psychotic symptoms. Adjusting for other psychiatric symptoms did not increase the specificity of the risk factors.
  
  
  CONCLUSIONS
  Socio-demographic risk factors for non-clinical psychotic symptoms in the general population are also risk factors for other psychiatric symptoms. The relationship between these risk factors and psychotic symptoms are for a substantial part explained by an increase in other psychiatric symptoms.
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands. E.J.Breetvelt@umcutrecht.nl
authors.forename: Elemi J
authors.initials: EJ
authors.lastname: Breetvelt
authors.forename: Marco P M
authors.initials: MP
authors.lastname: Boks
authors.forename: Mattijs E
authors.initials: ME
authors.lastname: Numans
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Selten
authors.forename: Iris E C
authors.initials: IE
authors.lastname: Sommer
authors.forename: Diederick E
authors.initials: DE
authors.lastname: Grobbee
authors.forename: René S
authors.initials: RS
authors.lastname: Kahn
authors.forename: Mirjam I
authors.initials: MI
authors.lastname: Geerlings
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology* / Q000503:physiopathology*; D008875:Middle Aged; D016017:Odds Ratio; D044382:Population Groups; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult