TY  - JOUR
T1  - Summer birth and deficit schizophrenia: A pooled analysis from 6 countries
AU  - Messias E, Kirkpatrick B, Bromet E, et al
Y1  - 2004/10/01
N1  - 10.1001/archpsyc.61.10.985
JO  - Archives of General Psychiatry
SP  - 985
EP  - 989
VL  - 61
IS  - 10
N2  - Background 
    In some reports, summer birth has been associated with deficit schizophrenia.
Deficit schizophrenia and nondeficit schizophrenia also differ in several
other ways.Objective 
    To conduct a combined analysis of the published and unpublished data
sets from the northern hemisphere that relate deficit and nondeficit schizophrenia
to month of birth.Data Sources 
    Studies of season of birth in which it was possible to make a deficit/nondeficit
categorization.Study Selection 
    Published studies with samples of convenience and all known population-based
studies with the deficit/nondeficit categorization were included. The studies
came from 6 countries.Data Extraction 
    Three published studies of samples of convenience, 2 population-based
prevalence studies, and 5 population-based studies that approximated incident
samples were included. Month of birth was compared for deficit and nondeficit
schizophrenia, using meta-analytic fixed-effects models.Data Synthesis 
    A group x month goodness-of-fit χ2 showed a significant
difference between deficit and nondeficit subjects in season of birth (P < .001) in the studies that approximated
incidence. This difference was largely due to an increase in deficit schizophrenia
births in June and July (odds ratio, 1.9; 95% confidence interval, 1.3-2.9).
Similar results were found in the prevalence studies. A similar pattern was
found in 2 of the 3 samples of convenience, but when combined, these 3 samples
did not show a significant deficit/nondeficit difference.Conclusions 
    Deficit schizophrenia has a season of birth pattern that differs from
that of nondeficit schizophrenia. This analysis supports the notion of a separate
disease within schizophrenia.
SN  - 0003-990X
M3  - doi: 10.1001/archpsyc.61.10.985
UR  - http://dx.doi.org/10.1001/archpsyc.61.10.985
ER  -