Left-Handedness and Likelihood for ADHD, Dyslexia

Left-Handed Studies

As reported by the Wall Street Journal, researchers have been exploring why left-handed people are more prone to brain disorders like dyslexia, schizophrenia and attention deficit hyperactivity disorder.

There is no evidence that left-handed people's IQs, on average, differ from right handed people, but left-handed people are more statistically likely to have mood disorders and afflictions such as schizophrenia.

The exact reasons for this are still unclear, but scientists speculate that it could be related to how the brain communicates between its two hemispheres. Right-handed people tend to rely on the left hemisphere of their brain, which controls language and communication.

Some 70 percent of left-handed people also rely on the left hemisphere, and 30 percent on the right hemisphere. The right hemisphere reliance could potentially put them at risk for brain disorders, though there is no conclusive evidence that this is the case. This is partially because the wiring of left-handed brains is different from right-handed brains, which makes studies more difficult.

Ten percent of the population is left-handed, including presidents Barack Obama and George H. W. Bush. Another interesting point raised in the article is that genetics are not solely responsible for determining hand dominance. Factors such as the age of the mother can increase the likelihood of a left-handed baby. 

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