title: Retinal response to light in young nonaffected offspring at high genetic risk of neuropsychiatric brain disorders.
abstract: BACKGROUND
  In neuropsychiatric brain disorders, such as schizophrenia (SZ) and bipolar disorder (BD), the biased effect of chronic drug therapy and the toxic effect of illness once installed constitute obstacles to the identification of valid biomarkers. Such biomarkers could lie at the level of retinal function where anomalies have already been reported in adults suffering from neuropsychiatric disorders. Here, we report a specific electroretinographic (ERG) anomaly in young nonaffected and nonmedicated offspring at high genetic risk (HR) of these disorders.
  
  
  METHODS
  Electroretinography was performed in 29 HR offspring having one parent affected by DSM-IV SZ or BD (mean age: 20.8 years, SD 4.4) and 29 healthy control subjects (mean age: 20.6 years, SD 4.2). The HRs' parents descended from multigenerational families affected by SZ or BD.
  
  
  RESULTS
  Rod ERG (b-wave amplitude at V(max)) in HRs was significantly lower than control subjects (p < .0001; effect size of -1.47), whereas the cone ERG V(max) showed no difference (p = .27). No effects of gender, age, and seasons of testing were observed. The anomaly in retinal response (rod V(max) b-wave amplitude) was observed independently of parents' diagnosis (SZ; p = .007, effect size of -1.09; BD: p < .0001, effect size of -1.88) and was present in both the younger and older HRs (effect size of -1.6 and -1.8, respectively).
  
  
  CONCLUSIONS
  A rod retinal response anomaly before the age of the disease incidence may represent an early and specific biomarker of risk with meaning for further genetic and prevention research.
authors.affiliation: Centre de recherche Université Laval Robert-Giffard, Québec G1J 2G3, Canada. marc.hebert@crulrg.ulaval.ca
authors.forename: Marc
authors.initials: M
authors.lastname: Hébert
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Gagné
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Paradis
authors.forename: Valérie
authors.initials: V
authors.lastname: Jomphe
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Roy
authors.forename: Chantal
authors.initials: C
authors.lastname: Mérette
authors.forename: Michel
authors.initials: M
authors.lastname: Maziade
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000150:complications / Q000235:genetics / Q000473:pathology*; D001927:Brain Diseases / Q000150:complications / Q000235:genetics / Q000473:pathology*; D016022:Case-Control Studies; D004596:Electroretinography / Q000379:methods; D005192:Family Health; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D011569:Psychiatric Status Rating Scales; D012160:Retina / Q000503:physiopathology*; D012307:Risk Factors; D012559:Schizophrenia / Q000150:complications / Q000235:genetics / Q000473:pathology*; D055815:Young Adult