The various aspects of the human brain and the dominance of the hand have interested researchers for a long time. A new study, published in the October 2013 issue of the magazine SAGE Opensuggests that among people with mental illnesses, left-handers are more likely to suffer from psychotic disorders like schizophrenia, rather than mood disorders.
“The human brain develops asymmetrically, such that some cognitive processes occur primarily on the left or right side. Variations in this laterality have been suggested to contribute to certain forms of mental illness, such as schizophrenia,” the authors write. of the study.
The American researchers examined 107 patients from a public psychiatric clinic to determine the frequency of left-handedness among certain groups treated for different mental disorders. They found that 11% of people with bipolar or mood disorders like depression were left-handed, which is close to the percentage of the general population. This figure goes up to 40% in people with schizophrenia or schizoaffective disorder.
The scientists took into account the various factors that could influence these results, such as variation in the lateralization of the brain, academic achievement or ethnicity. But “despite accounting for these variables, a large difference between psychotic patients and those with mood disorders remains intact,” they state, cited by the site MedicalXpress.
