May mixed-handedness reşect cerebral lateralization abnormalities in mental illnesses with psychotic features?

Objectives: Cerebral lateralization is defined as the anatomical and functional differences between two brain hemispheres. Hand preference is accepted as a functional cerebral lateralization. Deficits in lateralization have been reported in handedness, language and anatomical asymmetry in schizophrenia, but the relationship between these anomalies has been unclear the excess of non-right-handedness (mixed handedness-ambiguous handedness-left handedness) in patients with psychotic symptoms compared with normal controls has been reported in many studies.

Methods: This study aimed to examine the relation between handedness and psychotic symptoms identified from study participants consisted of 728 patients consecutively admitted to the psychiatry department of the NPISTANBUL Neuropsychiatry Hospital were included. Handedness was assessed using the Edinburgh Handedness Inventory, giving a lateralization score ranging from -100% (full-left-handedness) to +100% (full-right-handedness). All diagnoses were made by psychiatrists using DSM IV criteria for psychiatric disorders.

Results: According to the preliminary results of this research, we will evaluate the association between left-handedness and age, education, and psychiatric diagnosis. We argue that a deviation from normal cerebral lateralization, as indexed by mixed handedness, is associated with the psychosis phenotype.

Conclusion: Findings will be discussed in terms of how mixed-handedness may reşect cerebral lateralization abnormalities in mental illnesses with psychotic features.