Abnormality of smooth pursuit eye movement initiation: specificity to the schizophrenia spectrum?

Schizophrenia patients have a deficiency of smooth pursuit eye movement initiation. We addressed whether this deficit is specifically related to a predisposition for schizophrenia. Thirty-two relatives of schizophrenia patients, eight schizotypals, 13 psychiatric comparison, and 33 nonpsychiatric subjects were assessed on smooth pursuit initiation. The nonpsychiatric subjects had significantly higher eye accelerations than did subjects in the other three groups, who did not significantly differ. The relatives were subdivided into three groups: (a) those with a schizophrenia spectrum disorder (n = 4) performed similarly to the schizotypals; (b) those with a major depression history (n = 7) were similar to the psychiatric comparison subjects; and (c) those with no psychiatric history differed from the nonpsychiatric subjects only on 30 degrees/s targets. There was also a significant relationship between offspring and parent eye accelerations to 30 degrees/s targets (r = .476). These results suggest that pursuit initiation deficits may be associated with a nonspecific, genetically transmitted neurological abnormality among schizophrenia spectrum disorder subjects.