Social and cognitive functioning, urbanicity and risk for schizophrenia.
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.
Weiser
Mark
M
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
van Os
Jim
J
Reichenberg
Abraham
A
Rabinowitz
Jonathan
J
Nahon
Daniella
D
Kravitz
Efrat
E
Lubin
Gad
G
Shmushkevitz
Moti
M
Knobler
Haim Y
HY
Noy
Shlomo
S
Davidson
Michael
M
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