Yale University study: Left-handed people more likely to have psychotic disorders such as schizophrenia

3 Nov

Science Daily reported in the article, Lefties More Likely to Have Psychotic Disorders Such as Schizophrenia:

Being left-handed has been linked to many mental disorders, but Yale researcher Jadon Webb and his colleagues have found that among those with mental illnesses, people with psychotic disorders like schizophrenia are much more likely to be left-handed than those with mood disorders like depression or bipolar syndrome. 1 The new study is published in the October-December 2013 issue of the journal SAGE Open. About 10% of the U.S. population is left-handed. When comparing all patients with mental disorders, the research team found that 11% of those diagnosed with mood disorders such as depression and bipolar disorder are left-handed, which is similar to the rate in the general population. But according to Webb, a child and adolescent psychiatry fellow at the Yale Child Study Center with a particular interest in biomarkers of psychosis, “a striking of 40% of those with schizophrenia or schizoaffective disorder are left-handed….” Webb and his colleagues studied 107 individuals from a public outpatient psychiatric clinic seeking treatment in an urban, low-income community. The research team determined the frequency of left-handedness within the group of patients identified with different types of mental disorders. The study showed that white patients with psychotic illness were more likely to be left-handed than black patients. “Even after controlling for this, however, a large difference between psychotic and mood disorder patients remained,” said Webb. What sets this study apart from other handedness research is the simplicity of the questionnaire and analysis, said Webb. Patients who were attending their usual check-ups at the mental health facility were simply asked “What hand do you write with?” “This told us much of what we needed to know in a very simple, practical way,” said Webb. “Doing a simple analysis meant that there were no obstacles to participating and we had a very high participation rate of 97%. Patients dealing with serious symptoms of psychosis might have had a harder time participating in a more complicated set of questions or tests. By keeping the survey simple, we were able to get an accurate snapshot of a hard-to-study subgroup of mentally ill people — those who are often poverty-stricken with very poor family and community support.” http://www.sciencedaily.com/releases/2013/10/131031125319.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29

Citation:

Journal Reference:
1. J. R. Webb, M. I. Schroeder, C. Chee, D. Dial, R. Hana, H. Jefee, J. Mays, P. Molitor. Left-Handedness Among a Community Sample of Psychiatric Outpatients Suffering From Mood and Psychotic Disorders. SAGE Open, 2013; 3 (4) DOI: 10.1177/2158244013503166

Here is the Yale University press release:

By Karen N. Peart
October 31, 2013
Being left-handed has been linked to many mental disorders, but Yale researcher Jadon Webb and his colleagues have found that among those with mental illnesses, people with psychotic disorders like schizophrenia are much more likely to be left-handed than those with mood disorders like depression or bipolar syndrome.
The new study is published in the October-December 2013 issue of the journal SAGE Open. About 10% of the U.S. population is left-handed. When comparing all patients with mental disorders, the research team found that 11% of those diagnosed with mood disorders such as depression and bipolar disorder are left-handed, which is similar to the rate in the general population. But according to Webb, a child and adolescent psychiatry fellow at the Yale Child Study Center with a particular interest in biomarkers of psychosis, “a striking of 40% of those with schizophrenia or schizoaffective disorder are left-handed.”
“In general, people with psychosis are those who have lost touch with reality in some way, through hallucinations, delusions, or false beliefs, and it is notable that this symptom constellation seems to correlate with being left-handed,” said Webb. “Finding biomarkers such as this can hopefully enable us to identify and differentiate mental disorders earlier, and perhaps one day tailor treatment in more effective ways.” Webb and his colleagues studied 107 individuals from a public outpatient psychiatric clinic seeking treatment in an urban, low-income community. The research team determined the frequency of left-handedness within the group of patients identified with different types of mental disorders.
The study showed that white patients with psychotic illness were more likely to be left-handed than black patients. “Even after controlling for this, however, a large difference between psychotic and mood disorder patients remained,” said Webb. What sets this study apart from other handedness research is the simplicity of the questionnaire and analysis, said Webb. Patients who were attending their usual check-ups at the mental health facility were simply asked “What hand do you write with?” “This told us much of what we needed to know in a very simple, practical way,” said Webb. “Doing a simple analysis meant that there were no obstacles to participating and we had a very high participation rate of 97%.
Patients dealing with serious symptoms of psychosis might have had a harder time participating in a more complicated set of questions or tests. By keeping the survey simple, we were able to get an accurate snapshot of a hard-to-study subgroup of mentally ill people — those who are often poverty-stricken with very poor family and community support.”
Other authors on the study include Mary I. Schroeder, Christopher Chee, Deanna Dial, Rebecca Hana, Hussam Jefee, Jacob Mays, and Patrick Molitor. Citation: Sage Open vol. 3 no. 4 2158244013503166 (October-December 2013)

For interesting facts about left-handed people http://facts.randomhistory.com/facts-about-left-handedness.html

A 2011 Wall Street Journal article, The Health Risks of Being Left-Handed, highlighted some of the potential challenges faced by lefties:

On average there is no significant difference in IQ between righties and lefties, studies show, belying popular perceptions. There is some evidence that lefties are better at divergent thinking, or starting from existing knowledge to develop new concepts, which is considered an element of creativity. And left-handed people have salaries that on average are about 10% lower than righties, according to recent research performed at Harvard University that analyzed large income data bases, although findings of some earlier studies were mixed.
Left-handedness appears to be associated with a greater risk for a number of psychiatric and developmental disorders. While lefties make up about 10% of the overall population, about 20% of people with schizophrenia are lefties, for example. Links between left-handedness and dyslexia, ADHD and some mood disorders have also been reported in research studies. The reasons for this aren’t clear. Scientists speculate it could be related to a concept known as brain lateralization.
The brain has two halves. Each performs primarily separate, specialized functions, such as language processing, which mainly takes place in the left hemisphere. There is lots of communication between the hemispheres. Typically in right-handers, the brain’s left side is dominant. But this tendency doesn’t hold up with lefties, as scientists previously believed. Some 70% of lefties rely on the left hemisphere for their language centers, a key brain function, says Metten Somers, a psychiatrist and researcher who studies brain lateralization at Utrecht University Medical Center in the Netherlands. This doesn’t appear to present problems, scientists say. The other 30% of lefties appear to exhibit either a right-dominant or distributed pattern, Dr. Somers says. They may be more prone to impaired learning or functioning, and at greater risk for brain disorders, he says. Hemisphere dominance is typical and more efficient. Symmetry, in which neither side is dominant, is believed linked to disorders, researchers say. People with schizophrenia, for instance, exhibit more symmetrical activation of their brain hemispheres than those without the disorder, studies show.
In a 2008 study, Alina Rodriguez, a psychology professor at Mid Sweden University in Östersund who studies handedness, brain development and ADHD, found that left- or mixed-handedness in children was linked to a greater risk of difficulty with language as well as ADHD symptoms. In another study published last year in Pediatrics, involving nearly 8,000 Finnish children, Dr. Rodriguez found that mixed-handedness rather than left-handedness was linked to ADHD symptoms. And knowing that a child was mixed-handed and had ADHD symptoms at age 8 helped predict much more accurately than just knowing they had symptoms at that age whether the child would continue to have symptoms at age 16. (What happens when people are forced to switch from writing with their dominant hand to the other isn’t well known, experts say.) Research that suggests that there is a link between favoring the left hand and an increased risk of bipolar disorder and ADHD, among other conditions. Emily Nelson has details on Lunch Break.
One reason that not more is known about lefties is that many studies of how the brain works prohibit left-handers from participating because their brain wiring is known to be different, says Robin Nusslock, a psychology professor at Northwestern University in Evanston, Ill., who uses neuroimaging to study mood disorders.
Lefties have an advantage in sports such as tennis, fencing and baseball, when up against a righthanded competitor, but not in noninteractive sports such as gymnastics. A potential pathway between prenatal stress and brain wiring could be cortisol, the body’s main stress hormone, which can interfere with brain development, says Carsten Obel, a professor at the public-health department at Aarhus University in Denmark who has conducted research on the prenatal environment and risk of disease. Cortisol is able to pass over the placenta barrier to influence the baby.
Several studies show that stressful life events, such as the death of a loved one or job loss, during pregnancy increase the risk of having non-right-handed children. In one study of 834 Danish mothers and their 3-year-old children, Dr. Obel and his colleagues found that mothers who reported multiple stressful events during their third trimester of pregnancy and experienced distress were more than three times as likely to have a mixed-handed child, 17% compared with 5%, according to the 2003 paper published in Developmental Medicine & Child Neurology. Another large study followed 1,700 Swedish mothers and children until the kids were 5 years old. It found that mothers with depressive symptoms or who underwent stressful life events while pregnant were more likely to have left- or mixed-handed children. The work was published by Dr. Rodriguez and her colleagues in 2008 in the Journal of Child Psychology and Psychiatry. Experts suggest that left- and mixed-handedness could be used as a risk factor for possible psychiatric or developmental conditions, along with behavioral difficulties, such as having a hard time in school. The presence of such risk factors could prompt early evaluation for those conditions, they say. http://online.wsj.com/news/articles/SB10001424052970204083204577080562692452538

The best defense for parents is a good awareness of what is going on with their child. As a parent you need to know what is going on in your child’s world

Related:

GAO report: Children’s mental health services are lacking https://drwilda.com/2013/01/12/gao-report-childrens-mental-health-services-are-lacking/

Schools have to deal with depressed and troubled children: https://drwilda.com/2011/11/15/schools-have-to-deal-with-depressed-and-troubled-children/

Where information leads to Hope. © Dr. Wilda.com

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