Cannon M, Cotter D, Coffey V P, Sham P C, Takei N, Larkin C, Murray R M, O'Callaghan E
Br J Psychiatry. 1996 Mar;168(3):368-71. doi: 10.1192/bjp.168.3.368.
We investigated the hypothesis that prenatal exposure to the 1957 A2 influenza increases the risk of schizophrenia in adulthood.
We traced a cohort of individuals known to have been exposed to the 1957 influenza epidemic during gestation and an unexposed cohort matched for period of gestation and hospital of birth. Follow-up information on psychiatric illness in subjects was sought from two sources: maternal interview and psychiatric hospital admission data.
Follow-up information was obtained on 54% of the sample: 238 subjects from the influenza-exposed group and 287 subjects from the unexposed group. There was no increased risk of schizophrenia among the exposed cohort compared to the unexposed cohort (relative risk 1.1; 95% Cl 0.41-2.95), although there was an increase in depressive illness (relative risk 1.59; 95% Cl 1.15-2.19).
The association between prenatal influenza and an increased risk of schizophrenia in adulthood has thus far been found only in population-based data and is not supported by the present observational study which has information about exposure and outcome in individuals.
