Exploratory eye movements as a trait marker of schizophrenia

To clarify a genetic factor in the development of schizophrenia from a psychophysiological point of view, the exploratory eye movements that:we have shown to be specific to schizophrenia in healthy families of schizophrenics were investigated Eye movements of parents, siblings, and healthy cotwins of monozygotic discordant pairs were examined while they looked at S-shaped figures. The responsive search scores (RSSs) of both parents and siblings were similar to those of schizophrenics. In the RSS, there was a relationship between each pair in discordant twins. These results suggest that RSS shown in schizophrenics may be a trait marker for schizophrenia. Furthermore, eye movements of schizophrenics with schizophrenic family members in their first-degree relatives were measured. As the number of schizophrenic family members of schizophrenics increased, their RSS became lower. This result also indicates that RSS can be related to the genetic factors of schizophrenia.