Left-Handedness Among a Community Sample of Psychiatric Outpatients Suffering From Mood and Psychotic Disorders
From Sage Open
Researchers have long studied the connections between hand dominance and different aspects of the human brain. This study finds that among those with mental illnesses, left-handers are more likely to suffer from psychotic disorders such as schizophrenia than mood disorders. “Our results show a strikingly higher prevalence of left-handedness among patients presenting with psychotic disorders such as schizophrenia and schizoaffective disorder, compared to patients presenting for mood symptoms such as depression or bipolar disorder,” wrote the authors.
Authors examined 107 individuals from a public psychiatric clinic seeking treatment in an urban, low-income community and determined the frequency of left-handedness within the group of patients identified with different types of mental disorders. They found that 11% of those diagnosed with mood disorders such as depression and bipolar disorder were left-handed, which is similar to the rate in the general population, however, 40% of those with schizophrenia or schizoaffective disorder were left-handed. The authors discussed additional factors that might be tied to the connection between schizophrenia and left-handedness such the variation of brain lateralization, scholastic achievement or race.
The human brain develops asymmetrically, such that certain cognitive processes arise predominantly from the left or right side. It has been proposed that variations in this laterality contribute to certain forms of mental illness, such as schizophrenia. A convenient measure of brain laterality is hand dominance, and prior work has found that patients with schizophrenia are more likely to be left-handed than the general population. This finding is not consistent, however, and fewer studies have directly compared handedness between psychiatric diagnoses. We assessed hand dominance in 107 patients presenting to an outpatient psychiatric clinic with diagnoses of a mood or psychotic disorder. The prevalence of left-handedness was 11% for mood disorders, which is similar to the rate in the general population. It was 40% in those with psychotic disorders (adjusted odds ratio = 7.9, p < .001). The prevalence of left-handedness was much higher in psychotic disorders compared with mood disorders in this community mental health sample.
Jadon R. Webb, Mary I. Schroeder, Christopher Chee, Deanna Dial, Rebecca Hana, Hussam Jefee, Jacob Mays,and Patrick Molitor\\\
Left-Handedness Among a Community Sample of Psychiatric Outpatients Suffering From Mood and Psychotic DisordersSAGE Open October-December 2013 3: 2158244013503166, first published on October 30, 2013doi:10.1177/2158244013503166