title: Cognitive functioning prior to the onset of psychosis: the role of fetal exposure to serologically determined influenza infection.
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 span, 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.
authors.affiliation: Department of Psychiatry, Columbia University, New York, New York 10032, USA. le2194@columbia.edu
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Ellman
authors.forename: Robert H
authors.initials: RH
authors.lastname: Yolken
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Buka
authors.forename: E Fuller
authors.initials: EF
authors.lastname: Torrey
authors.forename: Tyrone D
authors.initials: TD
authors.lastname: Cannon
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000032:analysis; D002648:Child; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D009980:Influenza A virus; D009981:Influenza B virus; D007251:Influenza, Human / Q000453:epidemiology / Q000523:psychology* / Q000821:virology; D007361:Intelligence Tests; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011263:Pregnancy Trimester, Third; D011297:Prenatal Exposure Delayed Effects; D011618:Psychotic Disorders / Q000453:epidemiology / Q000523:psychology* / Q000821:virology
chemical_list: D000914:Antibodies, Viral