Saccadic disinhibition in patients with acute and remitted schizophrenia and their first-degree biological relatives

Objective: Performance on measures of saccadic inhibition and control was i nvestigated in a large family study of schizophrenia to evaluate the utilit y of using antisaccade task performance as an endophenotypic marker of gene tic liability for schizophrenia. Method: Ninety-five patients with acute schizophrenia and 116 of their firs t-degree biological relatives, 13 schizophrenia patients whose illness was in full remission, 35 patients with acute psychotic affective disorder, and 109 nonpsychiatric comparison subjects were administered antisaccade and p rosaccade tasks. Results: Both schizophrenia patient groups had a greater number of errors o n the antisaccade task than did the first-degree relatives and the affectiv e disorder group, which both had more errors than the comparison subjects. Among the first-degree relatives of the probands with acute schizophrenia, relatives of poor-performing patients performed worse on the antisaccade ta sk than relatives of patients with good performance. Reflexive errors were not likely the result of interfering psychotic symptoms, medication, or med ication side effects. Although the schizophrenia patients demonstrated othe r signs of saccadic abnormalities, these problems, which were not observed in their relatives even though they had high antisaccade error rates, seem unlikely to account for the higher antisaccade error rate of the schizophre nia patients. Conclusions: These findings suggest that saccadic disinhibition is strongly associated with the genetic liability for schizophrenia.