Phenotypic correlations between oculomotor functioning and schizophrenia-related characteristics in relatives of schizophrenic probands.

Abnormalities of visual pursuit tracking are frequent in the first-degree relatives of probands with schizophrenia. The relationship between oculomotor abnormalities and schizophrenia-related characteristics in those family members, however, has received little attention. Fifty-three first-degree relatives of 24 probands with schizophrenia were evaluated for the presence of schizophrenia-related characteristics using both interview (Schedule for Schizotypal Personalities) and questionnaire (Chapman scales). The family members also had their eye movements recorded during pursuit tracking tasks and scored for gain in both the frequency and time domains, and saccadic intrusions. Social-interpersonal schizophrenia-related features were significantly related to both time- and frequency-domain gain calculations. It appears that abnormalities in the smooth-pursuit oculomotor system may be associated with symptoms conjectured to be most closely related to a genetic diathesis for schizophrenia. These findings provide further evidence that oculomotor abnormalities may be related to risk for this disorder.