Eye Tracking and Mental Illness

Eye-tracking abnormalities are one of the most promising endophenotypes for schizophrenia. Eye-tracking dysfunction (ETD) involves a primary disturbance in the smooth pursuit system and a secondary disturbance involving saccadic disinhibition. Eye tracking has high heritability. Linkage has been reported between ETD and loci on chromosome 6p. Recurrence risk for ETD in first-degree relatives of schizophrenics is much higher than that of schizophrenia, suggesting that ETD may be a more penetrant pleiotropic expression of gene(s) that increase the risk for schizophrenia and may therefore have greater power to identify schizophrenia-susceptibility genes than the clinical phenotype alone.