Objective: The aim of the study was to investigate the cerebral lateralization patterns in right-handed medication-free patients with schizophrenia. We were also interested in studying the effect of antipsychotic treatment on the lateralization patterns and whether the lateralizaton patterns and the clinical symptoms were related.
Method: Nineteen right-handed medication-free patients with schizophrenia were compared with healthy controls on visuospatial and motor tasks with the Corsi’s cube placing test, finger tapping test, and the turning preference test. Diagnosis were confirmed by SCID-I interviews based on the DSM-IV criteria. Patients were either antipsychotic-naive or free of oral medication for at least 3 weeks and 6 months for depot medications. All subjects were right-handed. Tests were repeated after 3 weeks of antipsychotic drug treatment. Laterality indices were calculated in favor of right side for all tests [(right-left)/(right+left)].
Results: The left-turning tendency was not significantly different between patients and controls. Antipsychotic treatment had no significant effect on the left-turning tendency in the patient group. There were significant differences on laterality indices of the Corci’s cube placing test, before and after antipsychotic treatment. The laterality indices on the turning and finger-tapping tests were correlated.
Conclusion: It was found that antipsychotic medication decreased right hemispatial inattention in visuospatial tasks.
Key words: Schizophrenia, lateralization pattern, antipsychotic
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