title: Social and cognitive functioning, urbanicity and risk for schizophrenia.
abstract: BACKGROUND
  Previous work suggests that the association between urbanicity and schizophrenia may be greatest in those with pre-existing vulnerability.
  
  
  OBJECTIVE
  To test for synergism in risk of schizophrenia between population density and a combined exposure of poor premorbid social and cognitive functioning.
  
  
  METHODS
  For 371 603 adolescent males examined by the Israeli Draft Board on social and cognitive functioning, data on population density of place of residence and later hospitalisation for schizophrenia were obtained from population-based registries.
  
  
  RESULTS
  There was an interaction between population density (five levels) and poor premorbid social and cognitive functioning (interaction chi(2)=4.6, P=0.032). The adjusted increase in cumulative incidence associated with one unit change in population density was 0.10% in the vulnerable group (95% CI 0.019-0.18, P=0.015), nine times larger than that in the non-vulnerable group (0.011%, 95% CI 0.0017-0.020, P=0.021).
  
  
  CONCLUSIONS
  Risk of schizophrenia may increase when people with a genetic liability to the disorder, expressed as poor social and cognitive functioning, need to cope with city life.
authors: Department of Psychiatry, Sheba Medical Center, Tel-Hashomer, IDF, Division of Mental Health, and Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel. mweiser@netvision.net.il
authors: Mark
authors: M
authors: Weiser
authors: Jim
authors: J
authors: van Os
authors: Abraham
authors: A
authors: Reichenberg
authors: Jonathan
authors: J
authors: Rabinowitz
authors: Daniella
authors: D
authors: Nahon
authors: Efrat
authors: E
authors: Kravitz
authors: Gad
authors: G
authors: Lubin
authors: Moti
authors: M
authors: Shmushkevitz
authors: Haim Y
authors: HY
authors: Knobler
authors: Shlomo
authors: S
authors: Noy
authors: Michael
authors: M
authors: Davidson
mesh_terms: D000293:Adolescent; D015984:Causality; D003072:Cognition Disorders / Q000503:physiopathology; D015331:Cohort Studies; D020022:Genetic Predisposition to Disease; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007557:Israel / Q000453:epidemiology; D008297:Male; D011156:Population Density; D012042:Registries; D012559:Schizophrenia / Q000453:epidemiology* / Q000209:etiology; D012917:Social Adjustment