Biological relatives of patients with schizophrenia demonstrate an increased prevalence of schizotypal personality disorder symptoms, eye tracking deficits, and attentional disturbances. We investigated whether these hypothesized components of a schizophrenia-related phenotype are associated with one another or are independent in nonpsychotic relatives of patients with schizophrenia.
Eighty-three nonpsychotic first-degree relatives of 38 patients with schizophrenia and 45 control subjects without a psychiatric diagnosis underwent clinical evaluation, eye tracking evaluation, and the Continuous Performance Test (CPT) of visual attention.
Eye tracking qualitative rating was more powerful than quantitative eye tracking measures or CPT measures in discriminating relatives of patients with schizophrenia from control subjects. Correlations between neurocognitive variables and DSM-III-R schizotypal personality disorder symptom clusters suggested that CPT errors of omission are associated with positive schizotypal symptoms. Eye tracking measures were not significantly correlated with schizotypal symptoms or CPT errors in relatives of patients with schizophrenia.
Eye tracking deficits in the relatives of patients with schizophrenia are unrelated to CPT deficits and schizotypal symptoms. Eye tracking deficits and disturbances in visual attention may be separate components of a schizophrenia-related phenotype and should be considered as independent factors in genetic studies of schizophrenia.