Febrile seizures and risk of schizophrenia.
BACKGROUND
Febrile seizure is a benign condition for most children, but experiments in animals and neuroimaging studies in humans suggest that some febrile seizures may damage the hippocampus, a brain area of possible importance in schizophrenia.


METHODS
A population-based cohort of all children born in Denmark between January 1977 and December 1986 was followed until December 2001 by using data from nationwide registries.


RESULTS
We followed 558,958 persons including 16,429 with a history of febrile seizures for 2.8 million person-years and identified 952 persons who were diagnosed with schizophrenia. A history of febrile seizures was associated with a 44% increased risk of schizophrenia [relative risk (RR)=1.44; 95% confidence interval (CI), 1.07-1.95] after adjusting for confounding factors. The association between febrile seizures and schizophrenia remained virtually unchanged when restricting the analyses to people with no history of epilepsy. A history of both febrile seizures and epilepsy was associated with a 204% increased risk of schizophrenia (RR=3.04; 95% CI, 1.36-6.79) as compared with people with no such history.


CONCLUSIONS
We found a slightly increased risk of schizophrenia among persons with a history of febrile seizures. The association may be due to a damaging effect of prolonged febrile seizures on the developing brain, shared etiological factors, or confounding by unmeasured factors.
Vestergaard
Mogens
M
The Danish Epidemiology Science Centre, Department of Epidemiology and Social Medicine, University of Aarhus, Vennelyst Boulevard 6, building 260, DK-8000 Aarhus C, Denmark. mv@soci.au.dk
Pedersen
Carsten Bøcker
CB
Christensen
Jakob
J
Madsen
Kreesten Meldgaard
KM
Olsen
Jørn
J
Mortensen
Preben Bo
PB
D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D007223:Infant; D038801:International Classification of Diseases; D008297:Male; D011159:Population Surveillance / Q000379:methods; D012042:Registries; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000503:physiopathology; D003294:Seizures, Febrile / Q000453:epidemiology* / Q000503:physiopathology