COGNITIVE FUNCTIONING PRIOR TO THE ONSET OF PSYCHOSIS: THE ROLE OF FETAL EXPOSURE TO SEROLOGICALLY DETERMINED INFLUENZA INFECTION

Biol Psychiatry. 2009 Jun 15:65(12):1040-7

Ellman LM, Yolken RH, Buka SL, Torrey EF, Cannon TD

Department of Psychiatry, Columbia University, New York, New York 10032, USA. Le2194@columbia.edu

ABSTRACT:

BACKGROUND:

Previous studies have linked prenatal influenza exposure to increased risk of schizophrenia; however, no study has examined the neurodevelopmental sequelae of this prenatal insult before the onset of psychotic symptoms using serological evidence of infection. This study sought to examine the contribution of prenatal influenza A and B exposure to cognitive performance among children who developed psychoses in adulthood versus nonpsychiatric control children.

METHODS:

Subjects were 111 cases (70 with schizophrenia and 41 with affective psychoses) and 333 matched control subjects followed from gestation until age 7 through the Collaborative Perinatal Project. The Wechsler Intelligence Scale for Children (age 7) was administered and adult psychiatric morbidity was assessed by medical records review and confirmed by a validation study. Assays were conducted from archived prenatal maternal sera collected at birth, and influenza infection was determined by immunoglobulin G (IgG) antibody titers >75th percentile.

RESULTS:

Significant decreases in verbal IQ and the information subtest, as well as similar nonsignificant reductions in full scale IQ scores and vocabulary, comprehension, digit scan, and picture arrangement subtests were found among cases who were prenatally exposed to influenza B versus cases who were not exposed. Fetal exposure to influenza B did not lead to any significant differences in cognitive performance among control children.

CONCLUSIONS:

Cumulatively, these findings suggest that a genetic and/or an environmental factor associated with psychosis rendered the fetal brain particularly vulnerable to the effects of influenza B, leading to poorer cognitive performance even before symptom onset.