Retinal Response to Light in Young Nonaffected Offspring at High Genetic Risk of Neuropsychiatric Brain Disorders

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 BID (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; BID: 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.