Handedness, eyedness, and hand-eye crossed dominance in patients with schizophrenia: Sex-related lateralisation abnormalities

Schizophrenia is referred to as cerebral lateralisation abnormality. In this study the possible relationships among handedness, eye dominance, and crossed and non-congruent hand-eye dominance in patients with schizophrenia are investigated. A total of 88 patients with schizophrenia and 118 controls were included in the study. The patient group included 60 men and 28 women who ranged in age from 17 to 63 years. Diagnoses were made on the basis of information provided from clinical interviews and Structured Clinical Interview for DSM-IV. Handedness was ascertained by using the Edinburgh Handedness Inventory. Eye dominance was measured only by the near-far alignment test. Patients with schizophrenia had a significantly increased frequency of mixed-handedness and decreased frequency of both right- and left-handedness in comparison with controls. Also, the male patients with schizophrenia had significantly increased frequencies of left eye dominance, crossed hand-eye dominance, and non-congruent hand-eye dominance compared to controls, but not the female patients. Cerebral lateralisation abnormalities in schizophrenia may be associated with sex-related hormonal factors.