BACKGROUND:Several studies suggest a link between early-life infection and adult schizophrenia. Cross-sectional studies have reported: (1) increased prevalence of Epstein-Barr Virus (EBV), a
member of the Herpesviridae family in schizophrenia; (2) a possible role
of Herpes simplex virus in cognitive dysfunction in schizophrenia and
healthy controls. We report a longitudinal serological study of
early-life EBV infection, childhood IQ, and subsequent risk of psychotic
experiences (PE) in adolescence.
METHODS:Serum antibodies to EBV (anti-VCA IgG) were measured in 530 participants from
the ALSPAC cohort at age 4years. Assessments for IQ at age 9 and PE at
age 13 were attended by 401 and 366 of these individuals, respectively.
Logistic regression calculated odds ratio (OR) for PE in EBV-exposed,
compared with unexposed group. Mean IQ scores were compared between
these groups; effect of IQ on the EBV-PE association was examined.
Potential confounders included age, gender, ethnicity, social class,
household crowding, and concurrent depression and anxiety.
RESULTS:About 25% of the sample was exposed to EBV at age 4. EBV exposure was
associated with subsequent risk of definite PE in adolescence; OR 5.37
(95% CI 1.71-16.87), which remained significant after confounding
adjustment. EBV-exposed individuals compared with unexposed performed
worse on all IQ measures; mean difference in full-scale IQ 4.15 (95% CI
0.44-7.87); however, this was explained by socio-demographic
differences. The EBV-PE association was not explained by IQ.
CONCLUSIONS:Early-life exposure to EBV is associated with PE in adolescence, consistent with a
role of infection/immune dysfunction in the aetiology of psychosis.